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1
Chamayou, Anne-Christine [Verfasser], and Christoph [Akademischer Betreuer] Janiak. "Chiral metal-Schiff base complexes = Chirale Metal-Schiff-Base-Komplexe." Freiburg : Universität, 2011. http://d-nb.info/1115490567/34.
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Jensen, Svend Borup. "Schiff base calixarenes." Thesis, University of the West of Scotland, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246345.
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Four different synthetic routes to the sub-target, the p-tert-butylcalix[4lethylamine (6a) from thep-tert-butylcalix[4]arene (1a) have been examined. The best one was a 5-step synthesis, which gave an overall yield of65%. p-tert-Butylcalix[6]ethylamine (6b) and p-tert-butylcalix[8]ethylamine (6c) were synthesised from their respective p-tertbutylcalixarenes by the same route as the p-tert-butylcalix[4]ethylamine (6a). The three different amines (compound (6a), (6b) and (6c)) were used in 14 different Schiff -base type reactions which resulted in six Schiff-base compounds which were fully characterised by NMR, IR, FAB-ms and UV-vis. Insertion studies of the Schiff-base compounds along with template synthesis of the Schiff-base compounds were also attempted. The uptake of solid metal salt by the Schiff-base compounds in solution was examined by UV-vis spectroscopy. One of the Schiff -base compounds synthesised was the ferrocenecarboxaldehyde Schiff-base calix[4]arene (22a). An electrochemical analysis of this compound was undertaken to assess whether if it could be used as a sensor for metal ions. Molecular modelling of the Schiff-base compound and a crystal structure ofp-tert-butylcalix[4]ethylnitrile (8) are also presented in the thesis
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Leung, Alfred Chi Wook. "Conjugated schiff base-type metal-containing polymers." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/15889.
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The work in this thesis describes the synthesis and characterization of a series of
conjugated polymers containing Schiff base transition metal complexes. High molecular weight poly(salphenyleneethynylene)s (PSPEs) were synthesized using the Sonogashira-Hagihara protocol and they were characterized using nuclear magnetic resonance spectroscopy and gel permeation chromatography. Their optical properties were investigated by UV-vis and
fluorescence spectroscopies. PSPEs containing Zn saiphen moieties were found to exhibit strong aggregation that is facilitated by the presence of Zn to O interactions, and it was discovered that
the polymers interact with various Lewis bases to undergo aggregation and deaggregation. New ladder-type conjugated polymers, as well as a series of model compounds that are representative
of the repeating units of the polymers, were synthesized using Schiff base condensation methods. The electronic and magnetic properties of these ladder-polymers were studied using cyclic voltammetry, electron paramagnetic resonance spectroscopy, and magnetic susceptibility measurements.
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Wojciechowski, Paul E. "Electrochemistry of oxorhenium(V) Schiff base complexes." Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/25988.
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Najera, Blanca A. "Schiff base macrocyclic ligands and their complexes." Thesis, University of Sheffield, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301827.
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Armstong, Douglas Charles. "Schiff base and related complexes of iron." Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/37621.
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Edwards, David Ryan. "Towards liquid crystalline [3 + 3] Schiff-base macrocycles." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/31612.
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Conjugated Schiff-base macrocycles are interesting compounds of interest as platforms for catalysis, the preparation of novel synthetic ion channels and potentially as porous or tubular discotic liquid crystals. The preparation of organic macrocycles is typically low yielding, with polymerization competing with cyclization; the use of imines derived from the condensation of an aldehyde and an amine provides a means by which to conduct cyclizations under thermodynamic control and thereby improve yields. The use of difunctional aldehydes and amines allows for the formation of macrocycles in high yields without the need for high-dilution conditions. Two highly substituted dialdehydes also bearing phenolic and aikyl functionalities were prepared by several routes in an effort to obtain macrocycle precursors. These precursors were characterized and subsequently employed to prepare [3+3] Schiff-base macrocycles with a large number of appended aikyl and alkoxy substituents in hopes that they would display discotic liquid crystallinity.
A series of highly substituted [3+3] Schiff-base macrocycles was prepared and characterized by ¹H NMR, ¹³C NMR, UV-Vis, and IR spectroscopies in addition to MALDI-TOF mass spectrometry. The thermal properties of these macrocycles were also examined, and they were not found to display liquid crystalline mesophases either by differential scanning calorimetry or polarizing optical microscopy. A crystal structure of one of the macrocycles was obtained and was found to display structural features not previously observed in related macrocycles.<br>Science, Faculty of<br>Chemistry, Department of<br>Graduate
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Provençal, Alexandre. "Synthetic strategies for self-assembled schiff-base macrocycles." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/6048.
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Schiff-base macrocycles have interesting properties that could be used in new materials such as chemical sensors, catalysts and discotic liquid crystals. Triangular [3+3] Schiff-base macrocycles, for example, have been extensively studied in the MacLachlan group. However, few examples of [4+4] Schiff-base macrocycles have been reported. A square [4+4] Schiff-base macrocycle requires a precursor with the appropriate geometry such as compound 18. Synthesis of compound 18, however, proved to be problematic because of the formation of isomers, poor solubility and low yields. To avoid these issues, compound 36 was synthesized by Sonogashira coupling and was characterized by ¹H NMR spectroscopy, IR spectroscopy and HR-EI-MS. Reaction between compounds 36 and 37 led to the formation of an insoluble red solid. Although the characterization of this solid by NMR spectroscopy was not possible, MALDI-TOF data suggested that this solid contained the [4+4] Schiff-base macrocycle as the major product.
A new synthetic approach to compound 11, widely used for the formation of [3+3] Schiff-base macrocycles, was devised. The overall yield is about 10% higher than the original synthesis of compound 11. Aside from the higher yield, this synthetic approach has other advantages over the previous one such as it does not require a large excess of reagents or expensive chemicals, all steps can be achieved on large scales and little purification between each step is required. All new intermediates were characterized by ¹H NMR spectroscopy, ¹³C NMR spectroscopy, IR spectroscopy and HR-EI-MS.
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Jiang, Jian. "Studies of supramolecular chemistry through Schiff-base chemistry." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/27809.
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This thesis describes the synthesis, characterization, and host-guest studies of a series of Schiff-base macrocycles. New [2+2] Schiff-base macrocycles were prepared by Schiff-base condensation. These macrocycles were shown to be wide-mouthed supramolecular hosts that can include organic cations such as pyridinium, paraquat and ammonium derivatives. A new kind of donor-acceptor-donor 3-in-1 complex was obtained in solution by combining macrocycle, cyclobis(paraquat-p-phenylene) and tetrathiafulvalene.
Variations of these [2+2] Schiff-base macrocycles were prepared by modifying the substituents of the diformyl diol unit. In this way naphthalene-based macrocycles that undergo keto-enamine tautomerization were synthesized. These macrocycles can also combine with organic cations to form host-guest complex. The naphthalene-based [2+2] macrocycles can form lyotropic liquid crystals in chloroform and 1,2-dichloroethane. From the polarizing optical microscopy, it is proposed that the mesophases are lyotropic nematic liquid crystals based on a bilayer structure. A further study of these macrocycles shows that the host-guest complex can also form a lyotropic liquid crystalline phase.
Covalently-linked macrocycles with isosceles triangle shapes were prepared by Schiff-base condensation. The molecular isosceles triangles proved to also be supramolecular hosts for pyridinium and ammonium cations, based on ¹H NMR, 2D-ROESY NMR, and mass spectrometry studies.
In addition to the Schiff-base macrocycles, conjugated Schiff-base containing oligomers were synthesized via Gilch polymerization methods. The oligomers were characterized by gel permeation chromatography (GPC), thermogravimetric analysis (TGA) and UV-Vis spectroscopy. For further proof of the oligomeric structure, a model compound was prepared by the Wittig reaction.
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Black, Daniel. "Studies on binuclear Schiff-base compartmental ligand complexes." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363560.
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Branscombe, Neil D. J. "Studies on binuclear compartmental Schiff-base thiolate complexes." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299550.
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Givaja, Gonzalo. "Schiff-base polypyrrolic complexes of late transition metals." Thesis, University of Nottingham, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430509.
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Ryan, Sara Jane. "Dinuclear Schiff base complexes as models for metallobiosites." Thesis, University of Sheffield, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301587.
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Toner, Andrew Joseph. "Titanium-aluminium and titanium-alkyl Schiff base complexes." Thesis, Manchester Metropolitan University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361566.
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Archibald, Stephen James. "Complexes of tripodal and macrocyclic Schiff base ligands." Thesis, University of Edinburgh, 1995. http://hdl.handle.net/1842/14781.
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The synthesis, structures and physical properties of tripodal and macrocyclic Schiff base ligands and their complexes are described. All ligands are synthesised by the condensation of amines with 2,6-diformyl- or 2,6-diacetyl-phenols. The synthesis of a novel dodecadentate tripodal Schiff base ligand, L<SUP>1</SUP>H<SUB>3</SUB>, is described. Reaction of L<SUP>1</SUP>H<SUB>3</SUB> with Ln(ClO<SUB>4</SUB>)<SUB>3</SUB> where Ln=La, Pr gives complexes of the form [Ln(L<SUP>1</SUP>H<SUB>3</SUB>)(H<SUB>2</SUB>O)](CIO<SUB>4</SUB>)<SUB>3</SUB> and where Ln=Y, [Y(L<SUP>1</SUP>H<SUB>3</SUB>)](CIO<SUB>4</SUB>)<SUB>3</SUB>. The single crystal X-ray structures of L<SUP>1</SUP>H<SUB>3</SUB> and complexes are described. L<SUP>1</SUP>H<SUB>3</SUB> reacts with Gd(CIO<SUB>4</SUB>)<SUB>3</SUB> in the presence of Cu(CIO<SUB>4</SUB>)<SUB>2</SUB> and N,N-diisopropyl-ethylamine resulting in hydrolysis of the acetal functionality to give a complex of the nonadentate tripodal ligand L<SUP>5</SUP>H<SUB>3</SUB>, [Gd(L<SUP>5</SUP>H<SUB>3</SUB>)(H<SUB>2</SUB>O)<SUB>2</SUB>](CIO<SUB>4</SUB>)<SUB>3</SUB>, the single crystal X-ray structure of which is described. A similar reaction occurs with Ni(CIO<SUB>4</SUB>)<SUB>2</SUB>, giving [Ni(L<SUP>5</SUP>H<SUB>3</SUB>)](CIO<SUB>4</SUB>)<SUB>2</SUB>, The X-ray structure of which is also described. The preparation of L-H<SUB>3</SUB>, a related tripodal nonadentate ligand, is described and the structure determined by single crystal X-ray analysis. Complexes prepared by reaction with M(CIO<SUB>4</SUB>)<SUB>2</SUB>, M=Ni, Zn, are of the form [M(L<SUP>2</SUP>H<SUB>3</SUB>)](CIO<SUB>4</SUB>)<SUB>2</SUB> and the single crystal X-ray structures show the two complexes are isostructural. The Schiff base macrocycle [L<SUP>3</SUP>H<SUB>4</SUB>](PF<SUB>6</SUB>)<SUB>2</SUB> reacts to form [Cu<SUB>2</SUB>L<SUP>3</SUP>(CH<SUB>3</SUB>CO<SUB>2</SUB>)]Br preferentially in the presence of La(CIO<SUB>4</SUB>)<SUB>3</SUB> and Cu(CH<SUB>3</SUB>CO<SUB>2</SUB>)<SUB>2</SUB>. The single crystal X-ray structure is described. A template condensation of 2,6-diformyl-4-methylphenol and tris(2-amino-ethyl)amine around yttrium(III) yields a complex of the macrobicyclic ligand. L<SUP>6</SUP>H<SUB>3</SUB>, [Y(L<SUP>6</SUP>H<SUB>3</SUB>)(H<SUB>2</SUB>O)<SUB>2</SUB>](CIO<SUB>4</SUB>)<SUB>3</SUB>, the single crystal X-ray structure of which is described. [La(L<SUP>6</SUP>H<SUB>3</SUB>)(H<SUB>2</SUB>O)](CIO<SUB>4</SUB>)<SUB>3</SUB> was further reacted with Ni(CIO<SUB>4</SUB>)<SUB>2</SUB> in the presence of N,N-diisopropylethylamine to form the heterobimetallic complex [LaNi(L<SUP>1</SUP>)(H<SUB>2</SUB>O)](CIO<SUB>4</SUB>)<SUB>2</SUB>, the structure of which was confirmed by single crystal X-ray analysis. Preliminary magnetic studies on the complex [GdNi(L<SUP>1</SUP>)](CIO<SUB>4</SUB>)<SUB>2</SUB> indicate a weak ferromagnetic coupling between the metals.
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Chen, Zhengyu. "Disparate symmetries in head-to-tail Schiff-base macrocycles." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/60618.
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Two new Schiff-base macrocycles (called campestarenes) with 5-fold symmetry were prepared with bulky triphenylsilyl and triisopropylsilyl substituents. A single crystal structure of one campestarene showed an almost flat conformation of campestarenes are in their extreme enol-imine form. Tautomerization within the campestarene between the enol-imine and keto-enamine form was investigated by variable-temperature NMR and UV-vis spectroscopy. It was found that the molecule displays strong solvent- and temperature-dependent tautomerization that leads to large changes in color. These results were supported by computational investigations that showed the possibility of tautomerization between keto-enamine form and enol-imine form. The experimental studies showed the relative permittivity of solvents has a large influence on the relative stability of different campestarene tautomers in solution.
Some methyl/phenyl substituted campestarene precursors were prepared for macrocyclization of methyl/phenyl substituted campestarenes. Different synthetic conditions were tested to facilitate the formation of campestarens. One phenyl substituted campestarene was synthesized under acid condition.
Two new Pt₃ Schiff-base macrocycles with 3-fold symmetry were synthesized following a head-to-tail approach. Computational investigations showed an almost flat conformation of Pt₃ macrocycles. Aggregation of Pt₃ macrocycles in solid state was studied by MALDI-TOF, TEM and PXRD. It was found that Pt₃ macrocycles displays nanotubular structures due to aggregation. Aggregation of Pt₃ macrocycles in solution was investigated by variable-temperature 1D NMR and 2D NMR. The experimental results showed aggregation of Pt3 macrocycles at both high and low temperatures. Errata: http://hdl.handle.net/2429/60786<br>Science, Faculty of<br>Chemistry, Department of<br>Graduate
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Gallant, Amanda Jane. "New [3+3] Schiff-base macrocycles and their complexes." Thesis, University of British Columbia, 2006. http://hdl.handle.net/2429/30870.
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A series of conjugated [3+3] Schiff-base macrocycles containing both a central
crown ether-like pocket and three tetradentate N[sub 2]O[sub 2] binding sites were prepared and
investigated. The formation mechanism was investigated through the synthesis and study
of macrocycle fragments. Further understanding of the macrocycle conformations and
dynamics was obtained through computational studies.
A monoreduced macrocycle where one of the six imines has been reduced was
obtained as a by-product of macrocycle formation. Reactivity studies and deuterium
labeling investigations revealed that the selective reducing agent is likely a
benzimidazoline. This intermediate is generated in situ during the formation of the nonreduced
macrocycle and with macrocycle reduction is converted to a stable
benzimidazole unit.
Upon addition of small cations, the conjugated Schiff-base macrocycles assemble
into tubular structures. Spectroscopic and mass spectrometric studies have shown that the
cations bind to the crown ether-like centre of the macrocycle and induce aggregation to
form structures composed of alternating cations and macrocycles.
With the addition of seven equivalents of Zn[sup 2+] or Cd[sup 2+] to these fully conjugated
macrocycles surprising heptametallic complexes were obtained. Here, the trimetallated
macrocycle is first formed (with metal ions bound to the three N[sub 2]O[sub 2] pockets) and then
this templates the formation of a [M[sub 4]O][sub 6+] cluster that caps the cone-shaped macrocycle.
NMR studies indicated that these zinc complexes dimerize under certain solvent conditions forming capsule-like structures resembling cavitands used in host-guest
chemistry.
Variations of these [3+3] Schiff-base macrocycles were prepared by modifying
the substituents of the diformyl diol unit. In this way naphthalene-based macrocycles
were prepared. Studies on a series of related model compounds revealed that the ketoenamine
isomer is stabilized in these macrocycles rather than the enolimine isomer as
observed in the analogous phenyl-based macrocycles.<br>Science, Faculty of<br>Chemistry, Department of<br>Graduate
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Crook, B. V. "A study of homobinuclear and heterobinuclear Schiff base complexes." Thesis, University of East Anglia, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376081.
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Choudhary, Nosheen Fatima. "The chemistry of oxovanadium(IV) tetradentate Schiff base complexes." Thesis, University of Sussex, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244319.
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Jakubovic, David Andrew. "Metal complexes of water-soluble multidentate Schiff base ligands." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47487.
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Tancu, Yolanda. "Monofunctional and dendritic schiff base (N, N′) ruthenium carbene." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5261.
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Oshin, Kayode. "Synthesis, characterization, and application of chiral Schiff-base complexes." Diss., Kansas State University, 2011. http://hdl.handle.net/2097/8541.
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Doctor of Philosophy<br>Department of Chemistry<br>Christopher J. Levy<br>This work examines the synthesis of novel chiral Schiff-base complexes derived from (1R,2R)-cyclohexanediamine and (R)-[1,1’-binaphthalene]-2-2’-diamine structural backbones with quinoline, isopropyl-quinoline, and benzoquinoline structural side-arms. We incorporated some degree of flexibility in the ligands and complexes so they can accommodate the sterics of different substrates during a catalytic reaction. We successfully achieved this by reducing the imine bond in the ligands to the corresponding amine bond. Therefore, the successful reduction and metallation of some of these ligands to give structures of different symmetries is reported. We had difficulty reducing ligands with the binaphthalene backbone but were able to partially reduce the ligand through a one-pot reaction with a zinc(II) salt and NaBH4.
The complete 1H NMR assignments of the complexes reported in this thesis serve as a valuable tool for use in the characterization of future complexes. The complete NMR characterization of compounds reported is a complex process because they are polycyclic aromatic systems and the coupling network similarity in different parts of the molecule usually results in severe overlap of their 1H resonances. To overcome this impediment, we took advantage of various 2D-NMR techniques (COSY, NOESY, ROSEY, HSQC, and HMBC) along with other 1D-NMR experiments (1H HOMODEC, 1H, and 13C) to completely assign the desired complexes. Subsequently we also studied the coordination chemistry of several meal cations with our ligand system with the goal of obtaining single stranded monhelices.
The potential use of some of the complexes in the area of NMR discrimination and kinetic resolution of racemic mixtures was examined and shown to be promising. Several NMR experiments were conducted using the racemic olefins 3-buten-2-ol and 1-penten-3-ol to demonstrate the discriminating power of our silver(I) complexes. We discovered that sterics play an important role in this resolution experiment and the bulky nature of our complexes affect the overall efficiency of the NMR discriminatory process as it diminishes the contact between the reactive metal center and the olefins involved. Temperature also plays a vital role in the chiral recognition of racemic olefins as we examined the ideal temperature needed to reduce the various dynamic processes that take place in solution at room temperature.
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Degaonkar, M. P. "Synthesis and characterization of organotin (IV) schiff base complexes." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 1993. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2967.
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Marques, Fernando Mattiucci. "Catalisadores de rutênio coordenados à base de Schiff para polimerização via metátese." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/75/75135/tde-28112013-112154/.
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Essa pesquisa tem como meta estudar a atividade catalítica de complexos do tipo [RuCl2(PPh3)x(BS)] a partir de reações entre [RuCl2(PPh3)3] e os compostos do tipo Base de Schiff (BS) do tipo R1N=CHR2 onde os grupos R1 = cicloexil, fenil ou sec-butil, para aplicações em reações de polimerização via metátese por abertura de anel (ROMP) de norborneno (NBE). As reações foram realizadas na presença de etildiazoacetato (EDA) e os resultados dos complexos foram comparados em relação às características dos polímeros isolados em função da temperatura e do tempo de reação. Os complexos foram caracterizados por análise elementar CNH, espectroscopia na região do infravermelho e UV-Vis, RMN (31P; 1H) e voltametria cíclica. Os poliNBE apresentaram um σc = 0,41 determinado por RMN 13C. Experimentos realizados por 60 minutos a 25 °C na razão [NBE]/[Ru] = 5000 mostraram que o complexo [RuCl(PPh3)2(Ph)(IminCy)] formou 95% de poliNBE, enquanto que o complexo [RuCl(PPh3)2(Ph)(IminPh)] sintetiza 81,4% de NBE. Para o complexo [RuCl(PPh3)2(Ph)(IminBu)] sua atividade em ROMP para o NBE foi de 70,3%. Assim foi comparado a reatividade entre os ligantes Cy, Ph e Bu. Nas mesmas condições, apenas o complexo [RuCl(PPh3)2(Ph)(IminCy)] obteve melhora significativa no rendimento a 50 °C. Foram investigados também os efeitos de agentes promotores como ácido, sal e luz para a viabilização das reações de ROMP.<br>This research aims to study the activity of[RuCl2(PPh3)x(BS)] complexes by means of [RuCl2(PPh3)3] and Schiff base ligands (BS) R1N=CHR2where R1= cyclohexil, phenil and sec-butil groups, in order to catalyze ring opening metathesis polymerization (ROMP) reactions of norbornene (NBE). The reactions occur in presence of etyldiazoacetate (EDA) and was investigated according to the temperature and the time reaction. The complex was characterized by CNH elemental analysis, infrared, UV-vis spectra, NMR (1H; 31P) and cyclic voltametry. The polymer showed σc = 0,41 by NMR (13C). The experiments performed for 60 minutes at 25 °C with the ratio [NBE]/[Ru] = 5000 showed that [RuCl(PPh3)2(Ph)(IminCy)] complex obtained 95% of polyNBE, while that [RuCl(PPh3)2(Ph)(IminPh)] complex yielded 81,4% of NBE. However, the [RuCl(PPh3)2(Ph)(IminBu)] provided 70,3% of polyNBE. Under same conditions, only [RuCl(PPh3)2(Ph)(IminCy)] complex showed significant changes at 50°C. In addition, promoters agents with acids, salts and light were investigated with the aim at making the ROMP reactions feasible.
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Boden, Britta Nicole. "Investigations of highly conjugated macrocycles and polymers for aggregation and chemical sensing." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/269.
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With the goal of developing Schiff base macrocycles with conjugation extended over multiple aromatic rings, new phenanthrene and triphenylene-containing bis(salicylates) were synthesized. A convenient route to 3,6,9,10-tetraalkoxy-2,7-diiodophenanthrene was developed. This compound has been found to be a useful precursor for Pd-catalyzed cross-coupling reactions.
Macrocycles were synthesized by Schiff base condensation of the phenanthrene and triphenylene precursors. Reaction of smaller phenanthrene and triphenylene bis(salicylates) with 1,2-dialkoxy-4,5-phenylenediamine afforded macrocycles in poor yield and purity, but formation of the macrocycle was confirmed by mass spectrometry. Condensation of larger phenanthrene ethynylene bis(salicylates) with phenylenediamines formed [3+3] Schiff base macrocycles in good yield and could be purified through recrystallization. These two large macrocycles were weakly luminescent, and showed decrease in intensity of emission in solution over time. Addition of nitroaromatic compounds to solutions of the macrocycles caused quenching of luminescence, but Stern-Volmer constants could not be determined. One of the macrocycles aggregates in solution and shows some order in the solid state. Association constants for self-assembly of this macrocycle in chloroform were determined, and aggregation was found to be enthalpically driven and entropically disfavoured. Both large macrocycles can complex metals, but low solubility prevents thorough characterization of the metal complexes.
Phenanthrene-containing poly(phenyleneethynylene)s (PPEs) and poly(phenylenevinylene)s (PPVs) were synthesized via the Sonogashira and Heckcouplings, respectively. The PPEs had high molecular weight and both polymers were extremely luminescent with OF = 70% for the PPE and OF = 59% for the PPV. These polymers show potential for use in solar cells and nitroaromatic sensors
.
Dithienylsalphen monomers were made using 4-(2-thienyl)salicylaldehyde and 5-(2-thienyl)salicylaldehyde. These monomers were coordinated to Ni(II), Cu(II) and vanadyl, and tested for electropolymerization. Conjugated dithienylsalphen monomers polymerize poorly, while non-conjugated dithienylsalphen monomers form good films through electropolymerization. Ultraviolet-visible spectroscopy confirmed extended conjugation in N,N '-phenylenebis(4-(2-thienyl)salicylideneimine).
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Anselmo, Daniele. "Lewis acidic zn(ii) schiff base complexes in homogeneous catalysis." Doctoral thesis, Universitat Rovira i Virgili, 2013. http://hdl.handle.net/10803/127634.
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El trabajo descrito en esta tesis muestra estudios hacia nuevas aplicaciones de complejos derivados de bases de Schiff en catálisis homogénea. En concreto, se han investigadoligandos “salen” (incluyendo sistemas quelantes N2S2) ytambiénse han examinado otros aspectos que generalmente se consideran importantes en el contexto del aumento de la sostenibilidad de los procesos químicos. Estudios sobre el uso de estos compuestos acidos de Lewis en la catálisis de la fijación de dióxido de carbono, de reacciones de múltiples componentespara obtener indoles sustituidos y de reciclado de agregados supramoleculares basados en triptyceno han revelado un ancho potencial de aplicación. Los complejos Zn(salen) se han evaluadotambién como "espectadores" en la construcción de ligandos supramoleculares basados en fosfinas voluminosas que demostraron ser útiles en la catálisis de hidrosililación. Por lo tanto, el trabajo descrito en esta tesis puede servir como un punto de partida para el desarrollo de un nuevo potencial catalítico para los complejos de bases de Schiff.<br>The work described in this thesis shows studies towards new applications of Schiff base complexes in homogeneous catalysis . Specifically, we investigated “salen” ligands (including N2S2 chelating systems) and also examined other aspects that are generally considered important in the context of increasing the sustainability of chemical processes. Studies on the use of these Lewis acidic compounds in the catalysis of the fixation of carbon dioxide, multicomponent reactions for the synthesis of substituted indoles and the recycling of triptycene based supramolecular aggregates revealed a wide potential of application. The Zn(salen) compexeswere evaluated as "spectators" in the construction of supramolecular ligands based on bulky phosphines which proved to be useful in hydrosilylation catalysis. Therefore, the work described in this thesis may serve as a starting point for the development of a new catalytic potential of Schiff base complexes.
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Kim, Shang U. "SYNTHETIC EFFORTS TOWARD FUMONISIN via AMINO ACID SCHIFF BASE METHODOLOGY." Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/193674.
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Synthetic efforts toward fumonisin analog were described. These are accomplished via amino acid Schiff base methodology. These efforts can be divided three major phases. First, tandem reductive alkylation with DIBAL/TRIBAL and different types of organo-lithium or Grignard nucleophiles provided threo-amino alcohol with excellent stereoselecitivites (2-27:1). The reductive alkylation utilized most hydrocarbon nucleophiles, e.g. alkyl-, vinyl-, alkenyl-, phenyl-, and dienyl-, and afforded high selectivites unless donor solvents (e.g. THF and Et2O) were used. Second, syntheses of the protected threo-γ-amino-β-hydroxy aldehydes and their stereoselectivities were introduced. The reductive alkylated threo-amino allyl alcohol was transformed via Brown’s hydroboration/oxidation protocol with 9-BBN, followed by TEMPO oxidation to give the resultant aldehydes in reasonable yields. Then, TBDPS and Schiff base protected aldehyde was coupled with phenyl- and decyl Grignard reagents to obtain predominant 3,5-anti-diols (ca. 80:20 anti:syn), characterized by ¹³C NMR analysis of Rychnovsky’s 1,3-acetonide groups. Products can be useful analogues for fumonisin and 5-hydroxy-sphingosine due to their structural similarity. Third stage involved the synthesis of C₁₁-C₂₀ fragment analog of fumonisin. Chiral auxiliaries (e.g. Evans and Myers) were administrated for stereoselective methylation, Sharpless asymmetric dihydroxylation in the presence of (DHQ)2PHAL catalyst was performed to form 1,2- syn-diols, and the manipulation of protection/deprotection and Finklestein reaction furnished C₁₁-C₂₀ fragment analog of fumonisin.
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Parra, Diego Noé David. "Construção e otimização de uma plataforma sensorial eletroquímica a base de nano-metalopolimero poli[Ni(Salpn)]." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/75/75135/tde-22052018-133439/.
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Metalopolimeros são considerados excelentes materiais para a construção de eletrodos modificados quimicamente devido ao fato de apresentar propriedades essenciais, como por exemplo, uma alta atividade eletrocatalítica, eletroluminescia, aplicações na área da eletroquímica e eletroanalítica em atividades de eletrocatálise, quimioresistores, fotoeltrocatálise e desenvolvimento de sensores, respectivamente. Alguns complexos de metais de transição contendo Bases de Schiff como ligantes exibem propriedades eletrônicas não convencionais, que têm sido extensivamente estudadas para a aplicação no desenvolvimento de modelos sintéticos aos compostos biológicos como as metaloproteínas e metaloenzimas. O intuito principal desta tese foi o estudo da síntese, otimização e aplicação do nano-metalopolimero à base de poli[Ni(Salpn)] como plataforma sensorial eletroquímica, visando a obtenção de melhoras significativas em determinadas propriedades estruturais, catalíticas, dentre outras. Essas propriedades dependem, não somente do comportamento molecular, mas também, dos efeitos dos possíveis rearranjos estruturais devido às interações intermoleculares. Desta forma, foi construído e estudado o desempenho eletroquímico de uma plataforma sensorial à base de eletrodos constituídos com filmes poliméricos, sendo possível a avaliação de suas aplicações na determinação de substâncias com importância analítica nas áreas clínica, farmacêutica e ambiental. No âmbito que tange a síntese e caracterização do complexo Ni(Salpn), foi possível confirmar por meio de técnicas de caracterização de materiais a eficiência do métodos utilizados. Analogamente, a eletropolimerização foi realizada com sucesso, obtendo nano-filmes com espessura aproximada 110 nm com ótima atividade eletroquímica. A avaliação na aplicação do nano-metalopolímero poli[Ni(Salpn)] apresentou uma excelente resposta frente ao H2O2, possuindo uma rápida resposta, um intervalo linear de 49,9 a 1480 μmol L-1, com limite de detecção de 7,68 μmol L-1 e sensibilidade de 24,05 μÅ mmol-1, viabilizando assim a construção de uma plataforma sensorial viável, rápida, precisa e exata, com a finalidade de resolução de problemas analíticos.<br>Metalopolymers are considered to be excellent materials for the construction of chemically modified electrodes due to the fact that they present essential properties, such as high electrocatalytic activity, electroluminescence, electrochemical and electroanalytical applications in electrocatalysis, chemoresistors, photoeltrocatalysis and sensor development, respectively. Some transition metal complexes containing Schiff Bases as binders exhibit unconventional electronic properties which have been extensively studied for application in the development of synthetic models for biological compounds such as metalloproteins and metalloenzymes. The most aim of this thesis was to study the synthesis, optimization and application of nano-metallopolymer based on poly [Ni(Salpn)] as an electochemical sensorial platform, aiming at obtaining significant improvements in certain structural, catalytic properties, among others. These properties depend not only on molecular behavior but also on the effects of possible structural rearrangements due to intermolecular interactions. In this way, the electrochemical performance of a sensorial platform based on electrodes made with polymer films was constructed and studied, being possible the evaluation of its applications in the determination of substances with analytical importance in the clinical, pharmaceutical and environmental areas. In terms of the synthesis and characterization of the Ni(Salpn) complex, it was possible to confirm by means of techniques of material characterization the efficiency of the methods used. Analogously, the electropolymerization was performed successfully, obtaining nano-films with a thickness of approximately 110 nm with excellent electrochemical activity. The evaluation in the application of the poly[Ni(Salpn)] nano-metallopolymer showed an excellent response against H2O2, having a fast response, a linear range of 4.99 x 10-5 to 1.48 x 10-3 mol L-1, with detection limit of 7.68 x 10-6 mol L-1 and sensitivity of 24,05 μmol mmol-1, thus making possible the construction of a viable, fast, precise and accurate sensorial platform for the purpose of resolution of analytical problems.
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AGUSTIN, DOMINIQUE. "Bases de schiff et coordinences non usuelles du germanium, de l'etain et du plomb : (base de schiff)m(ii), (base de schiff)m = x et (base de schiff)m n = ml m (m = ge, sn, pb ; x = s, se, n-sime 3 ; m = w, cr, fe et mn ; n = 1, 2)." Toulouse 3, 1999. http://www.theses.fr/1999TOU30162.
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Ce travail concerne l'etude d'especes organometalliques stables des types >m, >m = y (y = o, s, se, n-sime 3) et (>m) nm (m : metal de transition) a metal 14 a coordinence non usuelle. Le premier chapitre est une mise au point bibliographique concernant les basses coordinences stables des types > m et (> m) nm (m = ge, sn, pb). Le deuxieme chapitre concerne la synthese et l'etude physicochimique des nouvelles especes divalentes l 2m (m = ge, sn, pb ; l 2 = base de schiff). Les donnees spectroscopiques soulignent la coordination intramoleculaire n-m-n. Des reactions de cycloaddition et la structure rx de l'adduit (salen)sn-3,5-di-tert-butyl-1,2-benzoquinone sont presentes. Des insertions d'aldehydes ou de clivage par des acides organiques et des chlorures d'acides conduisent, a partir de (salen)m, a de nouveaux composes divalents heteroleptiques. Le troisieme chapitre concerne les complexes (salen)m nm(co) 6 - n (m = ge, sn, pb ; m = cr, w, n = 1, 2) 2. Les structures rx indiquent le caractere double de la liaison sn = m. Les complexes (salen)m = m(co) 5 (m = ge, sn ; m = cr, w) conduisent, par des reactions de cycloaddition et de substitution de ligands, a de nouvelles especes a enchainement p-w-sn ou a des composes trimetalles sn-m-sn (m = cr, w). Le quatrieme chapitre decrit les complexes (salen)m = mncp(co) 2 (m = ge, sn, pb), (salen)sn = fe(co) 4 et leurs structures rx. Le caractere double de la liaison (salen)m-ml n, du au caractere -donneur et au fort caractere -accepteur de (salen)m, est demontre par l'obtention de la plus courte liaison sn-mn connue dans (salen)sn = mn(cp)(co) 2. La position axiale de (salen)sn dans la structure de (salen)sn = fe(co) 4 demontre que (salen)sn est plus -donneur que -accepteur vis-a-vis du fer. Le cinquieme chapitre traite de la reactivite des especes divalentes (salen)m vis-a-vis d'oxydants conduisant a de nouvelles especes insaturees de type (salen)m = y (m = ge, sn ; y = s, se, n-sime 3) ; certains aspects de leur reactivite sont egalement presentes. La derniere partie concerne des transferts de ligands entre (salen)sn et des composes halogenes (bf 3. Me 2o, cp 2ticl 2, nicl 2. Dppe, pcl 3, tbupcl 2, cl 3p = x (x = o, s)) conduisant a de nouveaux composes lineaires ou cycliques a ligand salen du bore, du titane, du nickel et du phosphore (neutres ou cationiques).
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Morale, Francesca. "Metallomesogens derived from Schiff-base chelates and related co-ordination chemistry." Thesis, University of Nottingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269486.
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Hunter, Mary Josephine. "Encapsulated metal ions : mononuclear complexes of Schiff-base macrocycles and cryptands." Thesis, Open University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277902.
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Xiang, Tengfei. "Synthesis and Characterization of Polymeric Schiff Bases from 2,5-Diformylfuran." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1353710697.
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Marrs, Deborah Jane. "Macrocycles, macrobicycles : a study." Thesis, Open University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.257447.
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Lo, Wing Kit. "Synthesis, characterization and luminescent properties of mono- and bi-metallic Schiff base complexes." HKBU Institutional Repository, 2004. http://repository.hkbu.edu.hk/etd_ra/585.
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Martin, Cibely da Silva [UNESP]. "Estudo e caracterização da eletropolimerização de moléculas nanoestruturadas a Base de Schiff." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/97778.
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martin_cs_me_sjrp.pdf: 1815881 bytes, checksum: f4bcade9143b72e80d41d79ebd336a65 (MD5)<br>A presente dissertação de mestrado apresenta o estudo da eletropolimerização de monômeros à base de Schiff na ausência de cátions metálicos (N,N’-bis(5-aminosalicilidenoimina) – NH2 -salen) e do monômero a base de Schiff contendo níquel como cátion metálico no centro ligante tetradentado (N,N’,N’’,N’’’-tetrabis(salicilideno)3,3’,4,4’-bifenileno tetramino de níquel (II)) – Ni2 (Bisalphen). A obtenção do monômero NH 2 -salen foi realizada pela redução metálica em meio ácido do monômero NO 2 -salen (N,N’-bis(5-nitrosalicilidenoimina)), sendo confirmada pela técnica de espectroscopia no infravermelho (FTIR), espectrofotometria na região de UV-vís e por espectroscopia de massa (MS-EI). As análises dos voltamogramas de eletropolimerização, e dos perfis voltamétricos em solução aquosa, demonstram um mecanismo de por acoplamento C–N. O mecanismo foi confirmado pelo estudo de velocidade de varredura e número de ciclos de potenciais, como também pela caracterização por espectroscopia Raman. Em solução aquosa o filme de poli(NH-salen) apresentou um único par redox na ausência de oxigênio molecular, atribuído ao par redox R 1 -NH-C-R 2 /R 1 -N=C-R 2 , onde um aumento da concentração de espécie eletroativa foi obtida em função do aumento da razão [carga do íon]/[raio iônico] dos ânions presentes em solução, que pode ser atribuído a necessidade da difusão dos ânions no processo de transferência eletrônica. Para comparação dos mecanismos de formação, a obtenção do filme polimérico do complexo metálico Ni 2 (Bisalphen) foi realizada de modo semelhante, modificando apenas o solvente e eletrólito suporte utilizado. Na etapa de eletropolimerização, os resultados foram satisfatórios somente em solvente THF contendo...<br>This dissertation presents the study of electropolymerization of monomers to the Schiff base in the absence of metal cations (N, N'-bis (5-amine-salicylideneimine) - NH2 -salen) and the Schiff base monomer containing nickel as metallic cation in the tetradentate center (N,N',N'',N'''-tetrabis(salicylidene) 3,3',4,4'-biphenylene-tetramine of nickel (II) - Ni2 (Bisalphen)). The NH 2 -salen monomer synthesis was realized by metallic reduction in acid medium from NO2 -salen (N,N'-bis(5-nitro-salicylideneimine)), being confirmed by the infrared spectroscopy (FTIR), UV-Vis spectrophotometry, and mass spectroscopy of electronic impact (MS-EI). The voltammetric profiles obtained on electropolymerization stage and in aqueous solution show the mechanism formation based on C-N coupling. This mechanism was confirmed by scan rate, potential cycle number study, and by the Raman characterization. In aqueous solution the poli(NH-salen) film showed one redox couple in absence of molecular oxygen, which was ascribed to R 1 -NH-C-R 2 /R 1 -N=C-R 2 redox couple. The increase of surface coverage was obtained in function of [ion charge]/[ionic radius] ratio of the anions present in aqueous solution, which can be ascribed to necessity of anion diffusion on electronic transfer. In order to compare the electropolymerization mechanism, the polymeric film of Ni2 (Bisalphen) was also obtained by electropolymerization technique. However, the solvent and supporting electrolyte were different. In the electropolymerization stage, the results were satisfactory only in THF solvent using the TBAP as supporting electrolyte, which can be ascribed to low solubility of complex in other solvents, as well as the low dipole value, necessary to propagation of the reaction. Due to presence of the metallic cation on monomer structure, the electropolymerizatiom... (Complete abstract click electronic access below)
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Frischmann, Peter David. "Supramolecular schiff base coordination chemistry : blueprints for self-assembling metallocavitands and nanotubes." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/26979.
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Heptametallic zinc(II) and cadmium(II) clusters have been isolated after reacting
the metal-acetate salts with large diameter [3+3] Schiff base macrocycles. Two tetrazinc
complexes have been characterized and identified as intermediates in the formation of the
heptazinc complexes. The heptametallic complexes are, in fact, templated by the Schiff
base macrocycles, a process that has been investigated with ¹H NMR spectroscopy and
single-crystal X-ray diffraction. In the solid-state the heptametallic complexes have a
bowl-shaped geometry, reminiscent of organic cavitands, leading to them being called
metallocavitands. Solid-state investigation of the heptazinc and heptacadmium
metallocavitands showed they organize into capsules with a cavity volume of 150 and
215 ų, respectively. Solution dimerization was also observed in aromatic solvents and
N,N-dimethylformamide (DMF). The thermodynamics of dimerization have been
quantified by van’t Hoff analyses of association constants measured with variabletemperature,
variable-concentration ¹H NMR spectroscopy. Both metallocavitands
exhibit entropy-driven dimerization in all solvents in which dimerization occurs. Unusual
for dimerization of cavitands, this entropy-driven process can be attributed to the
expulsion of solvent from the monomeric cavity upon dimerization.
Inside the cavity of heptacadmium metallocavitands is a μ₃-OH ligand where the
proton is located at the base of the cavity and is capable of hydrogen bonding with guest
molecules. The μ₃-OH proton resonance is observable in low temperature 1H NMR
spectra and exhibits two-bond J-coupling with three cadmium ions. Within capsules of
the heptacadmium metallocavitands there are eight Lewis-acidic sites accessible to guest
molecules, six unsaturated cadmium(II) centers and two μ₃-OH ligands. Solid-state
analysis shows that two DMF molecules are encapsulated in the heptacadmium capsule
where they each simultaneously exhibit a host-guest hydrogen-bond and a dative metalligand
interaction.
New methodology has been developed that facilitates synthesis of polydentate
[2+2] Schiff base macrocycles with unsymmetrical salphen pockets. Also a [3+3]
macrocycle with triptycenyl substituents has been synthesized to prohibit alkali-metal
induced solution aggregation.
The one-pot twelve component head-to-tail self-assembly of Pt₄ rings directed by
chelating imine-pyridyl donors has been demonstrated. These supramolecules exhibit
extensive columnar organization in both solution and the solid-state, a phenomenon that
imparts liquid crystalline properties on the macrocycles.
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Ramnauth, Ramkrishna. "Transition metal imido schiff base complexes : synthesis, structure, redox and catalytic chemistry." Thesis, Queen Mary, University of London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404705.
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Elvidge, Diane Lesley. "Structure and solvation of iron(II) Schiff base complexes and other ions." Thesis, University of Leicester, 1988. http://hdl.handle.net/2381/33665.
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The structure and solvation of ions are studied from different aspects using various kinetic, spectroscopic and thermodynamic techniques. The solvation of a wide range of ions, both simple and complex, is investigated by calculation of sets of single-ion transfer chemical potentials for a series of binary aqueous solvent mixtures. Observed trends are discussed in terms of the effects on ion solvation of solute and solvent structure and solute-solvent interactions. Structure, solvation and also reactivity of sane low- spin iron (II) di-imine complexes containing unsymmetrical Schiff base ligands are investigated using a variety of techniques. The occurrence of diastereoisomerism in complexes of this type is probed using complementary techniques which highlight different aspects of this phenomenon. Thus, the differing reactivities of, and the differing spatial orientations in, possible diastereoisomeric forms are utilized in detecting diastereoisomers by kinetic and 1H nmr spectroscopic methods respectively. In addition, for complexes of this type, links between structure, solvation and reactivity are investigated using kinetic data, solubility data, ultraviolet/visible absorption spectra and 1H nmr spectra obtained for the complex species.
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Kulmaczewski, Rafal. "Mechanisms of formation of pseudocalixarene Schiff base macrocycles investigated by ESI-MS." Thesis, Loughborough University, 2011. https://dspace.lboro.ac.uk/2134/9130.
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Starting from 4-substituted phenols, three dialdehydes were synthesised as Schiff base pseudocalixarene macrocyclic precursors. Two of the dialdehydes, 2,2'methylene-bis- [(6-hydroxymethyl)-4-methylphenol] and 2,2'-methylene-bis-[(6-hydroxymethyl)-4- phenylphenol] were structurally characterised. For the phenyl substituted compound condensation with 1,3-diaminopropan-2-ol, with transition metal ions as template, was investigated and a series of dinuclear complexes was synthesised and characterised by IR, FAB-MS and elemental analysis. The analytical data implied that the complexes have the same saddle shape conformation controlled by hydrogen bonds resulting from mono-deprotonation of the methylendiphenol units as was observed in previous work. A range of TM2M trinuclear complexes [TM = Cu(II), Ni(II) and M = Li(I), Na(I), Mg(II), Ca(II)] of (2+2) macrocycles was synthesised and characterised by IR, MS (FAB, ESI) and elemental analysis. Additionally [Cu2Ca(2+2)(NO3)2](MeOH)2 was characterised by X-ray crystallography. An ESI-MS was used to follow condensation reactions between 2,2'-methylene-bis-[(6- hydroxymethyl)-4-tert-butylphenol] and 1,3-diaminopropan-2-ol in solution with various templates. It was found that, when a transition metal is used alone, the reaction produces only the (2+2) macrocycle. Cu(II) produced equilibrium mixtures containing dicopper(II) and tricopper(II) species but Ni(II) and Zn(II) yielded only dinuclear complexes. When transition metal ions were used in combination with group 1 or group 2 metal ions, the size of the macrocycle and nuclearity of the complex depended on the synthetic route and nature of alkali or alkaline earth metal. Among the products identified in the ESI-MS spectra were trinuclear complexes of the (2+2) macrocycle, pentanuclear sandwich complexes of two (2+2) macrocycles, tetranuclear (3+3) complexes, pentanuclear (4+4) and hexanuclear (6+6) species. One of the routes resulted in formation of [BaCu4(4+4)]2+ ion via a [BaCu4(dialdehyde)4]2+ cluster which was established to be a double template process where both metals are necessary for formation of the macrocycle. The central Ba(II) ion holds the dialdehydes together and the Cu(II) ion orients the carbonyl groups for Schiff base condensation.
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BENABOUD, HOURIA. "Etude cinetique de la formation d'une base de schiff en milieu micellaire." Paris 6, 1991. http://www.theses.fr/1991PA066025.
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Le but de ce travail etait d'adapter les connaissances acquises au laboratoire sur les effets des milieux micellaires a des reactions chimiques faisant intervenir plusieurs etapes elementaires et comportant des transferts de charge. La reaction etudiee, dont le mecanisme est connu, (formation d'une base de schiff) a lieu en plusieurs etapes elementaires catalysees par le protons. Le premier chapitre presente les proprietes generales des tensioactifs et leur influence qualitative sur les reactions chimiques. Le second chapitre reprend ces proprietes sous l'angle quantitatif en reprenant le modele de la pseudo-phase. Un troisieme chapitre est conscre a l'etude cinetique du mecanisme de formation des bases de schiff en fonction du ph. Le quatrieme chapitre presente les principaux resultats experimentaux qui ont ete obtenus pour la reaction de la nitro-4-phenylhydrazine sur le benzaldehyde en presence de tensioactif positif (bromure d'alkyltrimethylammonium) ou negatif (dodecyltrimethylammonium) et dans un melange eau-methanol a 10% qui sert de base de comparaison, en etudiant l'influence de la concentration des reactifs, du ph et de la concentration des especes qui servent a fixer sa valeur (melange tampon). Compte tenu des effets observes, cette etude a necessite plusieurs milliers d'experiences cinetiques. Nos resultats font apparaitre, pour une reaction qui est essentiellement sujette a une catalyse generale, que la presence de micelles negatives entraine une acceleration non negligeable (vitesse moyenne multipliee par 10). En revanche on observe un effet catalytique des micelles positives, mais uniquement dans un faible domaine de ph, ce qui etait inattendu. Afin d'interpreter les resultats, il est necessaire de tenir compte de l'influence du tensioactif sur le taux de protonation de la phenylhydrazine qui a du faire l'objet d'une etude specifique. On peut alors montrer que le mecanisme general n'est pas modifie par la presence de systemes micellaires mais que ce sont les vitesses des differentes etapes qui sont affectees: de ce fait, l'etape cinetiquement determinante n'est pas toujours la meme selon les conditions experimentales. Le developpement theorique permet de calculer les valeurs numeriques des principaux parametres gouvernant la reaction et de donner une interpretation complete des differents phenomenes observes
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Martin, Cibely da Silva. "Estudo e caracterização da eletropolimerização de moléculas nanoestruturadas a Base de Schiff /." São José do Rio Preto, 2013. http://hdl.handle.net/11449/97778.
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Orientador: Marcos Fernando de Souza Teixeira<br>Banca: Luiz Henrique Dall'Antonia<br>Banca: Maria Valnice Zanoni<br>Resumo: A presente dissertação de mestrado apresenta o estudo da eletropolimerização de monômeros à base de Schiff na ausência de cátions metálicos (N,N'-bis(5-aminosalicilidenoimina) - NH2 -salen) e do monômero a base de Schiff contendo níquel como cátion metálico no centro ligante tetradentado (N,N',N'',N'''-tetrabis(salicilideno)3,3',4,4'-bifenileno tetramino de níquel (II)) - Ni2 (Bisalphen). A obtenção do monômero NH 2 -salen foi realizada pela redução metálica em meio ácido do monômero NO 2 -salen (N,N'-bis(5-nitrosalicilidenoimina)), sendo confirmada pela técnica de espectroscopia no infravermelho (FTIR), espectrofotometria na região de UV-vís e por espectroscopia de massa (MS-EI). As análises dos voltamogramas de eletropolimerização, e dos perfis voltamétricos em solução aquosa, demonstram um mecanismo de por acoplamento C-N. O mecanismo foi confirmado pelo estudo de velocidade de varredura e número de ciclos de potenciais, como também pela caracterização por espectroscopia Raman. Em solução aquosa o filme de poli(NH-salen) apresentou um único par redox na ausência de oxigênio molecular, atribuído ao par redox R 1 -NH-C-R 2 /R 1 -N=C-R 2 , onde um aumento da concentração de espécie eletroativa foi obtida em função do aumento da razão [carga do íon]/[raio iônico] dos ânions presentes em solução, que pode ser atribuído a necessidade da difusão dos ânions no processo de transferência eletrônica. Para comparação dos mecanismos de formação, a obtenção do filme polimérico do complexo metálico Ni 2 (Bisalphen) foi realizada de modo semelhante, modificando apenas o solvente e eletrólito suporte utilizado. Na etapa de eletropolimerização, os resultados foram satisfatórios somente em solvente THF contendo... (Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: This dissertation presents the study of electropolymerization of monomers to the Schiff base in the absence of metal cations (N, N'-bis (5-amine-salicylideneimine) - NH2 -salen) and the Schiff base monomer containing nickel as metallic cation in the tetradentate center (N,N',N'',N'''-tetrabis(salicylidene) 3,3',4,4'-biphenylene-tetramine of nickel (II) - Ni2 (Bisalphen)). The NH 2 -salen monomer synthesis was realized by metallic reduction in acid medium from NO2 -salen (N,N'-bis(5-nitro-salicylideneimine)), being confirmed by the infrared spectroscopy (FTIR), UV-Vis spectrophotometry, and mass spectroscopy of electronic impact (MS-EI). The voltammetric profiles obtained on electropolymerization stage and in aqueous solution show the mechanism formation based on C-N coupling. This mechanism was confirmed by scan rate, potential cycle number study, and by the Raman characterization. In aqueous solution the poli(NH-salen) film showed one redox couple in absence of molecular oxygen, which was ascribed to R 1 -NH-C-R 2 /R 1 -N=C-R 2 redox couple. The increase of surface coverage was obtained in function of [ion charge]/[ionic radius] ratio of the anions present in aqueous solution, which can be ascribed to necessity of anion diffusion on electronic transfer. In order to compare the electropolymerization mechanism, the polymeric film of Ni2 (Bisalphen) was also obtained by electropolymerization technique. However, the solvent and supporting electrolyte were different. In the electropolymerization stage, the results were satisfactory only in THF solvent using the TBAP as supporting electrolyte, which can be ascribed to low solubility of complex in other solvents, as well as the low dipole value, necessary to propagation of the reaction. Due to presence of the metallic cation on monomer structure, the electropolymerizatiom... (Complete abstract click electronic access below)<br>Mestre
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Afonso, Maria Beatriz Alves [UNESP]. "Complexos de rutênio(II) coordenados à Bases de Schiff derivadas de cicloalquilaminas como precursores catalíticos para ROMP de norborneno e ATRP de metacrilato de metila." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/150896.
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Previous issue date: 2017-05-12<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)<br>A investigação de sistemas catalíticos duais capazes de mediar as reações de polimerização por abertura de anel via metátese (ROMP) e de polimerização radicalar por transferência de átomo (ATRP) simultaneamente é de grande interesse e importância na obtenção de novos materiais com potencial de aplicação. Neste estudo, novos complexos de rutênio(II) coordenados a diferentes bases de Schiff derivadas de cicloalquilaminas (ciclopentil 1a, cicloexil 1b, cicloheptil 1c e ciclooctil 1d) foram sintetizados: [RuCl(CyPen-Salen)(PPh3)2] 2a, [RuCl(CyHex-Salen)(PPh3)2] 2b, [RuCl(CyHep-Salen)(PPh3)2] 2c e [RuCl(CyOct-Salen)(PPh3)2] 2d. As bases de Schiff e seus respectivos complexos de rutênio foram caracterizados por FTIR, UV-Vis, RMN e voltametria cíclica. Os complexos planejados foram avaliados como precursores catalíticos em reações de ROMP de norborneno (NBE) e em reações de ATRP de metacrilato de metila (MMA). As sínteses de polinorborneno (poliNBE) via ROMP com os complexos 2a-d como pré-catalisadores foram avaliadas sob diferentes condições de reação ([HCl]/[Ru], [EDA]/[Ru], [NBE]/[Ru] e temperatura). Os melhores rendimentos de poliNBE foram obtidos a 50 °C com razão molar [NBE]/[HCl]/[Ru] = 5000/25/1 na presença de 5 µL de EDA por 60 minutos. A polimerização de MMA via ATRP foi conduzida usando os complexos 2a-d na presença de etil-α-bromoisobutirato (EBiB) como iniciador. Os testes catalíticos foram avaliados em função do tempo de reação usando a razão molar [MMA]/[EBiB]/[Ru] = 1000/2/1. Todos os experimentos via ATRP foram conduzidos à 85 °C. A correlação linear do ln([MMA]0/[MMA]) em função do tempo na ATRP de MMA mediada pelos complexos 2a-d indica que a concentração de radicais permanece constante durante a polimerização. As massas moleculares aumentaram linearmente com a conversão com a diminuição dos valores de IPD, no entanto, as massas moleculares experimentais foram maiores do que as massas moleculares teóricas.<br>The investigation of dual catalytic systems able to mediate simultaneously ring-opening metathesis polymerization (ROMP) and atom-transfer radical polymerization (ATRP) reactions is of great interest and importance in obtaining new materials with potential for application. In the study, ruthenium(II) complexes of Schiff base derived from cycloalkylamines (cycloalkyl = cyclopentyl 1a, cyclohexyl 1b, cycloheptyl 1c and cyclooctyl) 1d were synthesized: [RuCl(CyPen-Salen)(PPh3)2] 2a, [RuCl(CyHex-Salen)(PPh3)2] 2b, [RuCl(CyHep-Salen)(PPh3)2] 2c and [RuCl(CyOct-Salen)(PPh3)2] 2d. The Schiff bases 1a-d and their respective RuII complexes 2a-d were characterized by FTIR, UV-Vis, NMR, and cyclic voltammetry. The complexes 2a-d were evaluated as catalytic precursors for ROMP of norbornene (NBE) and for ATRP of methyl methacrylate (MMA). The syntheses of polynorbornene (polyNBE) via ROMP with complexes 2a-d as pre-catalysts were evaluated under different reaction conditions ([HCl]/[Ru], [EDA]/[Ru], [NBE]/[Ru], and temperature). The highest yields of polyNBE were obtained with [NBE]/[HCl]/[Ru] = 5000/25/1 molar ratio in the presence of 5 µL of EDA for 60 minutes at 50 °C. MMA polymerization via ATRP was conducted using the complexes 2a-d in the presence of ethyl-α-bromoisobutyrate (EBiB) as initiator. The catalytic tests were evaluated as a function of the reaction time using the initial molar ratio of [MMA]/[EBiB]/[Ru] = 1000/2/1 at 85 °C. The linear correlation of ln([MMA]0/[MMA]) and time clearly indicates that the concentration of radicals remains constant during the polymerization and that the ATRP of MMA mediated by 2a-d proceeds in a controlled manner. Molecular weights increased linearly with conversion, however, the experimental molecular weights were higher than the theoretical ones.
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Conner, Elaine Margaret. "Novel metal conjugates as potential anti colitic agents." Thesis, University of Strathclyde, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249764.
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Challoner, Nicholas Ian. "Novel oligomeric and polymeric materials based upon the dibenzotetraaza[14]annulenes." Thesis, Sheffield Hallam University, 2000. http://shura.shu.ac.uk/19439/.
Full textAbstract:
The class of compounds known as the dibenzotetraaza[14]annulenes have been of particular interest over the past 25 years, with the initial impetus for research being the relationship they hold with the naturally occuring porphyrins. The main aim of the work undertaken was to establish the potential of dibenzotetraaza[14]annulene type systems for the development of novel materials whose applicable behaviour was likely to fall into one of the following three categories; liquid crystals, organic conductors, and chelating systems. Additionally the chemistry involved with the synthesis of these types of materials was interesting in its own right and provided a platform for the author to increase his own knowledge of chemistry. The research undertaken may be broadly classified into the following areas: 1. The preparation of linear Schiff base polymers, 2. The preparation of dibenzotetraaza[14]annulenes (metal complexes and free ligands), 3. The preparation of 1-D and 2-D unsymmetrical macrocyclic complexes, and 4. The preparation of polymeric materials incorporating dibenzotetraaza[14]annulenes both as part of the polymeric backbone and as pendant side chains in a comb type polymer. 1. The preparation of linear Schiff base polymers. The Schiff base condensation of phenylenediamines with malondialdehydes has enabled the preparation of materials of the type illustrated below. [chemical formula]. Examination of the materials by differential scanning calorimetry has shown that many of the materials exhibit interesting thermal transitions from one crystalline state to another. However the use of thermal microscopy has not shown any of these phases to be liquid crystalline transitions. 2. The preparation of dibenzotetraaza[14]annulenes (metal complexes and free ligands). An extensive array of dibenzotetraaza[14]annulenes have been prepared, generally by a one step process involving the reaction of ortho-phenylenediamine and various 2-substituted malondialdehydes in the presence of a suitable acid catalyst and solvent. [chemical formula]. 3. The preparation of 1-D and 2-D unsymmetrical macrocyclic complexes. The introduction of unsymmetricality into the dibenzotetraaza[14]annulenes has been of interest since dipole-dipole interactions between molecules may lead to enhanced crystalline stacking, which in turn has a direct effect on any liquid crystalline or semiconducting properties the material may exhibit. Consequently the preparation of unsymmetrical dibenzotetraaza[14]annulenes has been undertaken, which has often required extended stepwise synthetic reaction pathways involving the use of protecting reagents. Small quantities of pure materials have been prepared and are believed to be the first of their type. 4. The preparation of polymeric dibenzotetraaza[14]annulenes. The incorporation of dibenzotetraaza[14]annulenes into a polymeric system has been examined in two ways. The initial study concentrated on the incorporation of the macrocycle directly into the polymer backbone and involved the reaction of suitably functionalised dibenzotetraaza[14]annulenes with linking groups such as para-phenylenediamine. The additional study has focussed on a method of forming polymers which include the macrocyclic complexes as pendant side chains in a comb type polymeric arrangement (illustrated below). [chemical formula]. At present the prepartion of a polymer of this type has not been achieved. However an extensive study into the attachment of groups to the macrocycles which are capable of undergoing polymerisation has been undertaken which has established the potential use of the Gabriel synthesis of amines and the Wittig reaction as potential methods of attachment.
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Pietrangelo, Agostino. "Synthesis, structure and electrochemistry of thiopene-containing oligoacenes and metallated schiff base monomers." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/22317.
Full textAbstract:
The syntheses, structures, and electrochemistry of novel thiophene-containing oligoacenes
and metallated Schiff base monomers are reported. Bent anthradithiophenes (67-71) were prepared by the oxidative photocyclization of 1 ,4-dithienyl-2,5-divinylbenzenes (62-66) and their structural, spectroscopic, and electrochemical properties determined by x-ray crystallography, powder x-ray diffraction, cyclic voltammetry, and UV/vis absorption and fluorescence spectroscopies. The site-selective reactivity of the thiophene moieties enabled access to the diphenyl- and dialkyl-functionalized derivatives where the substituents significantly influence the solid-state packing order of the oligoacenes in single crystals and as thermally evaporated films. Cyclic voltammetry studies suggest that the parent 67 electrochemically polymerizes via an oxidative coupling mechanism through the thienyl c
carbons affording a poly-oligoacene polymer, a feature that was not observed in the functionalized derivatives.
Thiophene-containing metallated Schiff base monomers were electrochemically polymerized on Earth (1 g) and in microgravity (0 g) and the microscopic order of the subsequent polymer films probed by measuring the magnitude of the third-order nonlinear optical susceptibility tensor X (³). The metallated polymers grown under terrestrial conditions possess lower X (³) values than those grown in microgravity where gravity induced convection currents are suppressed, suggesting that buoyancy forces generated under terrestrial conditions disrupt the weak intermolecular interactions between polymer chains that ultimately give rise to improved microscopic order. Moreover, the X (³) enhancements were found to vary between Cu²⁺ polymers grown in microgravity that differed only in the length of the peripheral alkoxy substituents indicating that in addition to the metal centres, the length of the alkoxy substituent also influences the microscopic order of the polymer films. A series of Pd-containing oligothiophenes were electrochemically polymerized onto carbon fiber electrodes and their catalytic activity investigated through a variety of C-C cross-coupling reactions. The polymers possessed the same catalytically active Pd-sites but differed in their connectivity to the polythiophene backbone, a factor that influenced their electrochemistry and film quality. Poly-100 proved to be an efficient catalyst for intra- and intermolecular C-C crosscoupling reactions (i.e., Suzuki, Heck, Sonogashira). X-ray photoelectron spectroscopy and control experiments suggest that polymer and metal ion-leaching is negligible during the course of the reactions, proving that poly-100 is a heterogeneous catalyst.
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Pop, Mihaela Diana. "Symmetrical and asymmetrical Salen-type Schiff-base ligands and their transition metal complexes." Thesis, University College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408061.
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Griffiths, Kieran. "Catalytic and topological aspects of Schiff base supported 3d-4f polynuclear coordination complexes." Thesis, University of Sussex, 2018. http://sro.sussex.ac.uk/id/eprint/75278/.
Full textAbstract:
The work presented in this thesis deals with the employment of Schiff base ligands used to synthesise novel 3d-4f polynuclear coordination clusters (PCCs) and the investigation into their potential magnetic, luminescent and catalytic properties. Chapter one provides a general introduction to the chemistry described in the thesis. It includes a general overview of 3d-4f PCC chemistry and the applications of these materials and previous synthetic strategies for the preparation of Schiff base PCCs. A rationale is presented for the ligands employed in the thesis and a synthetic strategy is devised for the synthesis of specific materials. The initial chapters are focused on the synthesis of 3d-4f PCCs with novel core topologies and the study of their magnetic properties. Several novel series of 3d-4f PCCs are presented with unique core topologies which are previously unobserved in 3d-4f PCC chemistry. In addition, some of the presented PCCs display single-molecule magnet (SMM) properties or a significant magnetocaloric effect (MCE). Chapter five bridges synthetic aspects discussed in the previous chapters, with a synthetic study targeting 3d-4f PCCs with a defect dicubane core (2,3M4-1) and introduces the term “isoskeletal” to describe PCCs which possess the same topology or related organic structures with the same host framework but different guests. Chapters seven to nine are focused on the development of a well characterised isoskeletal family of 3d-4f PCCs with a defect dicubane core and the investigation of their potential catalytic properties in a range of organic reactions including Michael Addition, Friedel-Crafts alkylations and multicomponent reactions. Characterisation of the 3d-4f PCCs is emphasised and verifies the stability of the 2,3M4-1 core in solution. An attempt at understanding the catalytic system and mechanistic aspects is undertaken, which is not explored in previously reported 3d-4f PCC co-operative catalysis. Chapter ten provides an overall conclusion to the work presented in the thesis, whilst highlighting the contributions of this work to the reported literature.
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Solanki, Nayan Kumar. "The copper chemistry of substituted 2,6-Bis pyrazolyl pyridines and schiff base ligands." Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621813.
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Santos, Sinara de Fátima Freire dos. "Determinação da estrutura cristalográfica e estudo teórico de compostos de base de Schiff." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/75/75135/tde-05072017-145546/.
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Nos últimos anos, têm-se notado o aumento do número de pesquisas relacionadas aos complexos de metais de transição com base de Schiff devido a suas interessantes estruturas e amplas aplicações, isso se deve em parte a formação de complexos estáveis, apresentando um papel importante na química de coordenação. A determinação estrutural dos átomos nas moléculas é necessária para que suas propriedades químicas, físicas e biológicas possam ser compreendidas. Para esta finalidade, existe uma grande variedade de técnicas químicas e físicas, na qual podemos citar a Difração de Raios X. Os avanços computacionais dos últimos anos e sua agregação na ciência, proporcionou um crescimento nas pesquisas que utilizam métodos teóricos, pois possibilitou sua aplicação em diversas áreas que dependiam de tão evolução para continuação de seus estudos. Vale ressaltar, que o uso de cálculo teórico têm apresentado um grande interesse pelos pesquisadores da área da Química, seja para a compreensão das suas estruturas ou para o estudo dos mecanismos de reações. Logo, o objetivo desse trabalho é a investigação estrutural de bases de Schiff, através da determinação das estruturas cristalinas por difração de raios-X. A partir dos dados cristalográficos foram avaliados parâmetros geométricos, interações intermoleculares, onde ambos os dados foram comparados com os da literatura obtendo resultados satisfatórios. A estrutura ASZ, apresentou estrutura semelhante com a esperada, obtendo-se índices de discordância R = 0,0774, wR2 = 0,2302, o que caracteriza um refinamento eficiente. A molécula possui um eixo cristalográfico de ordem 2 e grupo pontual 2/m. O complexo Zn(apy-epy), obteve bons índices de discordância R = 0,0621, wR2 = 0,2172, centrossimétrica, apresentando grupo pontual mmm com eixo de ordem 2. O átomo central de zinco tem geometria bipiramidal ligada a 6 átomos de nitrogênio. O ligante CW2-10A, foi a estrutura que obteve o melhor valor de discordância R = 0,0348, wR2 = 0,0902 e grupo pontual 2/m. A estrutura determinada, estava de acordo com o esperado. A estrutura final do complexo com sigla CuDenim, estava de acordo com o proposto, com um índice de discordância satisfatório R = 0,0746, wR2 = 0,2122, também apresentou uma interação do metal Cu com átomos de oxigênio do íon perclorato. O complexo CW1-53A, possui alguns átomos desordenados e foi preciso que fossem refinados isotropicamente, apresentou índices de discordância dentro do ideal R = 0,0436, wR2 = 0,1227. Os cálculos de frequência vibracional não identificaram frequências imaginárias para nenhuma das estruturas otimizadas. A estabilidade química foi explicada pelo gap HOMO-LUMO, bem como os locais de interações intermoleculares foram explicados através dos mapas de superfície Hirshfeld e pelo mapa de potencial eletrostático.<br>In recent years, has been an increase in studies related with Schiff-bases transition metal complexes due to their interesting structures and wide applications. One reason for this is the formation of stable complexes, presenting an important role in coordination chemistry. The structural determination of the atoms in the molecules is necessary in understanding in their chemical, physical and biological properties. For this purpose, there is a great variety of chemical and physical techniques, in which we can mention X-ray Diffraction. The computational advances of the last years and their aggregation in science, provided to growth in the researches that use theoretical methods, as it allowed its application in several areas that depended on so to continue their studies. It is worth mentioning that the use of theoretical calculus has shown a great interest by researchers in the field of Chemistry, either to understand their structures or to study the mechanisms of reactions. Therefore, the objective of this work is the structural investigation of Schiff bases, through the determination of the crystalline structures by X-ray diffraction. Where all the structures presented good indexes of disagreement and the obtained structures were within the expected one. From the crystallographic data, geometric parameters, intermolecular interactions were evaluated, and both data were compared with those of the literature, obtaining satisfactory results. The structure ASZ, presented similar to the one expected, with discordance indices R = 0,0774, wR2 = 0.2302, therefore characterizing the refinement. The molecule has a crystallographic axis of order 2 and a point group 2 / m. The complex Zn (apy-epy), obtained good discordance indices R = 0.0621, wR2 = 0.2172, centrossimetric, presenting a point group mmm with axis of order 2. The central zinc atom has bipyramidal geometry attached to 6 nitrogen atoms. The ligand CW2-10A was the structure that obtained the best discordance value R = 0.0348, wR2 = 0.0902 and 2/m point group. The structure determined was as expected. The final structure of the complex with CuDenim acronym, was in agreement with the with satisfactory discordance index R = 0.0746, wR2 = 0.2122, also presented a Cu metal interaction with oxygen atoms of the perchlorate ion. The complex CW1-53A, has some disordered atoms and had to be refined isotropically. It presented disagreement indices within the ideal R = 0.0436, wR2 = 0.1277. The vibrational frequency calculations did not identify imaginary frequencies for any of the optimized structures. The chemical stability was explained by the HOMO-LUMO gap, as well as the sites of intermolecular interactions were explained through the Hirshfeld surface maps and the electrostatic potential map.
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Lacelle, Thomas. "Design and Synthesis of Lanthanide Single-Molecule Magnets Using the Schiff Base Approach." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36064.
Full textAbstract:
Single-Molecule Magnets (SMMs) are discrete molecules that exhibit slow relaxation of magnetization. Unlike conventional magnets that rely on the long range magnetic ordering in the form of domains, these molecules act as magnets independently, that is without the influence of neighbouring molecules. SMMs have intrigued physicists and chemists alike for over twenty years with their potential future applications in data storage quantum computing, and with this communal interest there has been significant collaboration between the two fields of research. SMMs have brought forth an opportunity for coordination chemists to muster their creativity and synthetic expertise in the rational design and development of these magnetic materials. From these new and fascinating compounds, both experimental and theoretical physicists have sought to develop and refine our understanding of the aspects of these molecular magnets in order to improve their performance at higher temperatures.
In this work, new topologies for lanthanide complexes are explored using a novel Schiff base ligand. The magnetic properties of dinuclear, tetranuclear and octanuclear lanthanide complexes are discussed and correlated to their structural properties. The rational design of tetrazine-based Schiff base ligands for magnetic studies is also discussed in hopes of developing high performance SMMs.