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Christoforou, M. "Lone-pair effects in tin (II) materials." Thesis, City University London, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233894.
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Fontaine, Christophe. "Hétéroépitaxie par jets moléculaires de semiconducteurs II-VI." Grenoble 1, 1986. http://www.theses.fr/1986GRE10062.
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Etude de l'heteroepitaxie de cdte, cd::(1-x)zn::(x)te et cd::(x)hg::(1-x)te sur cdznte, insb et gaas (001) et (111) et des differents parametres qui gouvernent la qualite cristalline. Il s'avere que la croissance (001) est meilleure que la croissance (111). L'interet d'une interface graduelle est demontre a fort desaccord de maille. A faible desaccord de mailles les contraintes dans les couches epitaxiques ont ete mesurees. Dans ces conditions experimentales, la relaxatioon des couches est gouvernee par un mecanisme de generation de dislocations et non par l'activation thermique des dislocations presentes. Les modeles existants ne permettent pas de decrire la relaxation dans les couches cdte. Presentation d'un modele qui rend compte des observations
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Janin, Emmanuelle. "Adsorption and bonding on platinum : influence of the surface structure and chemical composition." Doctoral thesis, KTH, Physics, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3079.
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<p>This thesis deals with the influence of the structure andchemical composition of platinum surfaces on the adsorption ofsome molecules. Three main lines can be distinguished : 1) thecharacterisation of clean/modified surfaces, 2) the adsorptionof some simple atoms and molecules on these surfaces andfinally 3) the adsorption of 2-butenal, a bi-functionalmolecule containing a C=C group conjugated with a C=O group.The main tools used in this work are scanning tunnellingmicroscopy, photoelectron spectroscopy and high-resolutionelectron energy loss spectroscopy, in combination with quantumchemical calculations.</p><p>The platinum (111)(1× 1) and (110)(1× 2) surfacesare chosen as substrates. Pt(111) is a non-reconstructedclose-packed surface, while the Pt(110) surface is open, due toits missing row (MR) reconstruction, which results in thealternation of ridges, {111} microfacets and valleys. Titaniumgrows on Pt(111) in a Volmer-Weber mode. Pronounced reactionsbetween Pt and Ti are detected already at room temperature asthe Ti2p and Pt4f<sub>7/2</sub>core-level shifts are characteristic of the Pt<sub>3</sub>Ti alloy. Carbon segregated on the (110) surfaceappears as extended graphitic regions, which smoothen thesubstrate. Sn deposition at room temperature on Pt(110) resultsin the appearance of small islands, randomly spread over thesurface. The presence of mobile Sn ad-atoms and Pt-Sn-Ptalloyed chains in the valley of the MR reconstruction is alsoevidenced. Annealing the surface results in the rearrangementof the tin in the surface layer, together with a globalshortening of the terraces in the [110]direction and anincreased density of (1× n) (n>2) defects.</p><p>The adsorption of atomic hydrogen and oxygen has beenperformed on the Pt(111)( √ 3x √3)R30º surfacealloy and on Pt(110)(1× 2) respectively. The adsorptionsite of these atoms is changed as compared to the onedetermined on the clean Pt(111) surface (i.e. fcc hollow site): H is adsorbed on-top site on the (√3× √3)surface alloy, and O sits on the ridge of the missing rowreconstruction in bridge site. Carbon monoxide adsorption wasperformed on Pt(111) and Pt(110)(1× 2) surfaces, modifiedor not by tin. On the unmodified (111) surface, CO adsorbsfirst in top site, thenin bridge. Changing the geometry of thesurface to the (110) results in the vanishing of the bridgesite population. Modifying these surfaces by Sn does not changethe CO adsorption site.</p><p>Finally, 2-butenal (CH<sub>3</sub>-CH=CH-CH=O) has been adsorbed at 100 K on thePt(111) surface and the Sn/Pt(111) surface alloys. On theunmodified Pt surface, comparison with results obtained forpropene (CH<sub>2</sub>=CH-CH<sub>3</sub>) adsorption evidences the involvement of the C=Cgroup of the 2-butenal molecule in the bonding to the Ptsurface. The carbonyl group is also suggested to take part inthe bonding, through a σ<sub>cc</sub>η<sub>1</sub>(O) configuration. This carbonyl group bondingdisappears when Sn is alloyed to the surface, and the formationof a new physisorbed phase is detected.</p>
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Horsefield, Rob. "The crystal structure of complex II and analysis of its quinone binding site." Thesis, Imperial College London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.416597.
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Beck, Urs Heinrich Georg. "Synthesen und NMR-spektroskopische Untersuchungen von Ruthenium(II)phosphinkomplexen ; Crystal and molecular structure of /." [S.l : s.n.], 1987. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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Letcher, Robert J. (Robert James) Carleton University Dissertation Chemistry. "(1,3-bis(2'-pyridylimino)isoindolinato)Ni(II) complexes of phenylcyanamido ligands: crystal structure, solution and spectroscopic properties." Ottawa, 1991.
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Diller, Thomas Cabot. "Crystal structure of a deletion mutant of the type II[beta] regulatory subunit of cAMP-dependent protein kinase /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2000. http://wwwlib.umi.com/cr/ucsd/fullcit?p9970670.
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Maurer, Joshua Ahab Grubbs Robert H. Dougherty Dennis A. "I. Structure-function analysis of the mechanosensitive channel of large conductance. : II. Design of novel magnetic materials using crystal engineering /." Diss., Pasadena, Calif. : California Institute of Technology, 2003. http://resolver.caltech.edu/CaltechETD:etd-10202002-002307.
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Marko, Rodić. "Kompleksi Co(III), Ni(II) i Cu(II) sa hidrazonima nekih 2-piridil-ketona." Phd thesis, Univerzitet u Novom Sadu, Prirodno-matematički fakultet u Novom Sadu, 2015. https://www.cris.uns.ac.rs/record.jsf?recordId=95722&source=NDLTD&language=en.
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U disertaciji su opisane sinteze i fizičko-hemijske karakterizacije 32 kompleksa kobalta(III), nikla(II) i bakra(II) sa ligandima S-metilizotiosemikarbazonom 2-acetilpiridina (HL¹), bis(S-metilizotiosemikarbazonom) 2,6-diacetilpiridina (H₂L²), tiosemikarbazonom-S-metilizotiosemikarbazonom 2,6-diacetilpiridina (HL³), 1-adamantoilhidrazonom 2-acetilpiridina (HL⁴) i 1-adamantoilhidrazonom di(2-piridil)-ketona (HL⁵).Kako ligandi HL³, HL⁴ i HL⁵ do sada nisu bili sintetisani, dobijeni rezultati ujedno predstavljaju i prve iz njihove koordinacione hemije. Iako je sa S-metilizotiosemikarbazonom 2-acetilpiridina poznato nekoliko kompleksa, do sada nijedan od njih nije strukturno okarakterisan, tako da su rezultati prikazani u ovoj disertaciji dali jasnu sliku o načinima koordinacije HL¹. Takođe, kako je sa H₂L² poznat vrlo malo broj kompleksa, dobijeni rezultati su dali značajan doprinos razumevanju koordinacione hemije ovog liganda.Gotovo svi sintetisani kompleksi (njih 27 od 32) su strukturno okarakterisani metodom rendgenske kristalografije. Odabrana jedinjenja su ispitana metodama termičke analize, a utvrđena je njihova antimikrobna i citotoksična aktivnost. <br>This thesis describes syntheses and physico-chemical characterizations of 32 complexes of cobalt(III), nickel(II) and copper(II), with ligands 2-acetylpyridine S-methylisothiosemicarbazone (HL¹), 2,6-dicetylpyridine bis(S-methylisothiosemicarbazone) (H₂L²), thiosemicarbazone-S-methylisothiosemicarbazone 2,6-dicetylpyridine (HL³), 2-acetylpyridine 1-adamantoylhydrazone (HL⁴), and di(2-pyridil)-ketone 1-adamantoylhydrazone (HL⁵).Since the ligands HL³, HL⁴, and HL⁵ were not synthetized hitherto, the obtained results are the first regarding their coordination chemistry as well. Even though there are several complexes reported with 2-acetylpyridine S-methylisothiosemicarbazone as a ligand, none of them was structurally characterized. Therefore, here presented results gave clear insight into coordination modes of the HL¹. Moreover, since there is limited number of complexes with H₂L² reported hitherto, the obtained results gave significant contribution to understanding of its coordination chemistry.Almost each synthetized complex (27 out of 32) was structurally characterized by means of single crystal X-ray crystallography. The selected compounds were characterized by thermal analysis, and their antimicrobial and cytotoxic activity were determined.
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Castiglione, Michael. "Computer simulation of superionic fluorides." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365812.
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Paula, Elgte Elmin Borges de. "Síntese e caracterização espectroscópica de complexos de Co(II), Ni(II) e Cu(II) envolvendo espécies oxocarbônicas e ligantes nitrogenados derivados piridínicos." Universidade Federal de Juiz de Fora (UFJF), 2009. https://repositorio.ufjf.br/jspui/handle/ufjf/4432.
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Previous issue date: 2009-07-30<br>FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais<br>Este trabalho consiste na síntese e caracterização de complexos inéditos envolvendo as espécies oxocarbônicas ácido esquárico e croconato, o pseudo-oxocarbono croconato violeta, bem como os ligantes nitrogenados derivados piridínicos 4,4’-dimetil-2,2’-bipiridina (MBP), 1,3-bis(4-piridil)propano (BPP) e 2,3,5,6-tetraquis(α-piridil)pirazina (TPP) e os sítios metálicos de Co(II), Ni(II) e Cu(II). Adicionalmente realizou-se sínteses envolvendo o sítio metálico de Mn(II). Utilizou-se diversas técnicas analíticas e espectroscópicas para a caracterização dos compostos sintetizados, tais como, análise elementar (CHN), análise térmica (TG/DTA) e espectroscopia vibracional (IV e Raman). Foram obtidos seis complexos envolvendo a espécie esquarato, dos quais três contêm o ligante 4,4’-dimetil-2,2’-bipiridina (MBP), denominados: [Co(MBP)2(C4O4)] (1), [Ni(MBP)3](C4O4).3H2O (2) e {[Cu2(MBP)2(C4O4)2(H2O)4]}n (3) e três o ligante 2,3,5,6-tetraquis(α-piridil)pirazina (TPP): [Co2(TPP)(C4O4)2(H2O)2)]2H2O (4), [Ni2(TPP)(C4O4)(H2O)2Cl2]7H2O (5) e [Cu2(TPP) (H2O)2Cl2)] (C4O4)2H2O (6). Os complexos (2), (3) e (6) tiveram suas estruturas determinadas por difração de raios X de monocristal. O composto (3) apresentou-se como um polímero de coordenação que se estende em uma dimensão através do ligante esquarato, coordenado em ponte entre dois sítios de Cu(II) pelo modo µ-1,2-bis(monodentado). O referido ligante oxocarbônico apresentou-se nos compostos (2) e (6) como contra-íon. As sínteses envolvendo a espécie oxocarbônica croconato de potássio levaram à obtenção de sete compostos inéditos denominados: {[Co(MBP)2(NO3)]2+.[Co(C5O5)2(H2O)4]2-} .6H2O (7), [Ni(MBP)2(C5O5)] (8), [Cu(MBP)(C5O5)(H2O)] (9), {[Mn2(BPP)2(C5O5)2(H2O)4].3H2O}n (10), {[Co2(BPP)2(C5O5)2(H2O)4].2H2O}n (11), {[Ni2(BPP)3(C5O5)2(H2O)4].5H2O}n (12) e {[Cu(BPP)(C5O5)(H2O)3]}n (13), em que MBP consiste no ligante nitrogenado 4,4’-dimetil-2,2’-bipiridina e BPP no 1,3-bis(4-piridil)propano. Os compostos (7), (8) e (10) tiveram suas estruturas determinadas por difração de raios X de monocristal. O complexo (7) apresentou-se dinuclear, sendo constituído por uma porção catiônica e outra aniônica que apresenta dois íons croconato coordenados pelo modo monodentado, enquanto que (8) é mononuclear com o diânion croconato coordenado ao Ni(II) pelo modo 1,2-bidentado, tais complexos apresentaram arranjos supramoleculares, sendo que em (7) a presença de interações de hidrogênio estendem o arranjo em duas dimensões e em (8) interações do tipo empacotamento π estende o arranjo supramolecular em uma dimensão. O composto (10) apresentou-se como um polímero de coordenação bidimensional em que tanto o ligante nitrogenado BPP, numa conformação TG (trans-gauche), quanto um dos diânions croconato, apresentaram-se coordenados em ponte entre dois sítios metálicos de Mn(II). Tal rede polimérica apresenta caminhos fechados cuja topologia estrutural é (6,3). O referido polímero apresenta dois íons croconato com modos de coordenação distintos, um deles se coordena ao sítio de Mn(II) pelo modo 1,2-bidentado e outro em ponte pelo inusitado modo µ-1,2-bis(monodentado), o qual não apresenta relatos na literatura. Observou-se que a folha bidimensional apresentou-se entrelaçada paralelamente à outra folha equivalente, gerando uma estrutura interpenetrada. Através das sínteses envolvendo o pseudo-oxocarbono croconato violeta obteve-se dois compostos denominados: [Co(MBP)2(CV)] (14) que envolve o ligante nitrogenado 4,4’-dimetil-2,2’-bipiridina (MBP) e {[Mn(BPP)2(H2O)2](CV)2-.2H2O}n (15) que envolve o ligante 1,3-bis(4-piridil)propano (BPP). O composto (15) teve sua estrutura determinada por difração de raios X de monocristal, a qual apresenta dois ligantes BPP, numa conformação TG (trans-gauche), coordenados em ponte entre dois sítios de Mn(II) gerando um arranjo polimérico unidimensional em que os diânions croconato violeta atuam como contra-íons. Observou-se a presença de interações de hidrogênio na estrutura, as quais foram responsáveis pelos arranjos supramoleculares bi e tridimensional.<br>This work presents the synthesis and characterization of novel complexes of Co(II), Ni(II) and Cu(II) involving the oxocarbons species, squaric acid and croconate ion, the pseudo-oxocarbon croconate violet dianion as well as the nitrogen ligands derived from pyridine 4,4’-dimethyl-2,2'-bipyridine (MBP), 2,3,5,6-tetrakis(α-pyridyl)pyrazine (TPP) and 1,3-bis(4-pyridyl)propane (BPP). Additionally, some syntheses involving the Mn(II) metal ion were realized. We used various analytical and spectroscopic techniques for characterization of the compounds such as elemental analysis (CHN), thermal analysis (TG/DTA) and vibrational spectroscopy (IR and Raman). We obtained six complexes involving the species squarate. Three of them contain the ligand 4,4’-dimethyl-2,2'-bipyridine (MBP), named: [Co(MBP)2 (C4O4)] (1), [Ni(MBP)3](C4O4).3H2O (2) and {[Cu2(MBP)2(C4O4)2(H2O)4]}n (3) and the other three contain the ligand 2,3,5,6 tetrakis(α-pyridyl)pyrazine (TPP): [Co2(TPP)(C4O4)2(H2O)2)]2H2O (4), [Ni2(TPP)(C4O4)(H2O)2Cl2]7H2O (5) and [Cu2(TPP)(H2O)2Cl2)](C4O4)2H2O (6). The complexes (2), (3) and (6) had their structures determined by single crystal X-ray diffraction analysis. The compound (3) is an one-dimensional coordination polymer extended through squarate ion coordinated to the Cu(II) sites in the µ-1,2-bis(monodentate) bridging mode. The oxocarbon ligand acts as counter-ion in compounds (2) and (6). The synthesis involving the croconate ion led to the taking of seven novel compounds named: {[Co(MBP)2(NO3)]2+[Co(C5O5)2(H2O)4]2-}.6H2O (7), [Ni(MBP)2(C5O5)] (8), [Cu(MBP)(C5O5)(H2O)] (9), {[Mn2(BPP)2(C5O5)2(H2O)4].3H2O}n (10), {[Co2(BPP)2(C5O5)2(H2O)4].2H2O}n (11), {[Ni2(BPP)3(C5O5)2(H2O)4].5H2O}n (12) and {[Cu(BPP)(C5O5)(H2O)3]}n (13). The compounds (7), (8) and (10) had their structures determined by single crystal X-ray diffraction analysis. The complex (7) is dinuclear, consisting of one cationic and one anionic portion that has two croconate ions coordinated to the metal center in a monodentate fashion, while compound (8) is mononuclear with croconate dianion coordinated to Ni(II) in the 1,2-bidentate mode. In compound (7) it can be noticed the presence of hydrogen interactions extending the arrangement into two dimensions, while in (8), π-π stacking interactions extend the supramolecular arrangement in one dimension. Compound (10) is a two-dimensional coordination polymer where both BPP nitrogen ligands adopt a TG (trans-gauche) conformation. The polymer has two croconate ions with different coordination modes, one adopts the 1,2-bidentate mode and the other acts in an unusual -1,2-bis(monodentate) bridging mode, which has no reports in the literature. This 2-D polymer network presents (6,3) structural topology. Two 2-D sheets interlocked each other in a parallel way generating an interpenetrated structure. Through the synthesis involving the croconate violet dianion was obtained two compounds, named: [Co(MBP)2(CV)] (14) and {[Mn(BPP)2(H2O)2](CV).2H2O)]}n (15). Compound (15) had its structure determined by single crystal X-ray diffraction analysis. It has two BPP ligands, in the TG (trans-gauche) conformation, bridging two sites of Mn(II) generating a one-dimensional polymeric array in which the croconato violet dianions act as counter-ions. There is the presence of hydrogen bonding interactions in the structure which are responsible for the extension of the supramolecular arrangements into two and three dimensions.
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Zhu, Jiang. "PART I CRYSTAL STRUCTURE OF A DIMERIZATION DOMAIN OF DROSOPHILA CAPRIN. PART II CHARACTERIZATION OF TWO CAS13B CRISPR-CAS SYSTEMS FROM PORPHYROMONAS GINGIVALIS." OpenSIUC, 2018. https://opensiuc.lib.siu.edu/dissertations/1503.
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PART I: CRYSTAL STRUCTURE OF A DIMERIZATIO DOMAIN OF DROSOPHILA CAPRIN Drosophila Melanogaster Caprin (dCaprin) shares conversed HR1 domain with Caprin protein family members, which are RNA binding proteins that play critical roles in many important biological processes, such as synaptic plasticity, stress response, innate immune response and cellular proliferation. One of the Caprin protein family members, Caprin-1, is involved in the pathway of several human diseases, including breast cancer, neurodegenerative disorders, osteosarcoma, hearing loss, and viral infection. The functions of Caprin protein relies on their molecular interactions. Several direct interactions have been established between Caprin-1 and the Fragile X mental retardation protein (FMRP), Ras-GAP SH3 domain-binding protein 1 (G3BP1), and the Japanese encephalitis virus (JEV) core protein. We have determined the crystal structures of a fragment (residues 187-309) of Drosophila Melanogaster Caprin (dCaprin), which mediates homodimerization through a substantial interface created by a mainly alpha-helical fold. A larger hollow surface is created by homodimerization suggesting a protein binding groove. The FMRP binding should not affect dCaprin homodimerization for an integral alpha-helix in the dimeric dCaprein which formed by the FMRP interacting sequence motif. PART II: CHARACTERIZATION OF TWO TYPE VI-B CRESPR SYSTEMS: PGI5CAS1B AND PGI8CAS13B WHICH EFFECTOR PROTEINS ARE CAPABLE OF PROCESSING PRE-CRRNA INTO MATURE CRRNA CRISPR-Cas adaptive immune system protects microorganism from foreign nucleic acids invasion through endonucleases activity guided by RNA, which system has turned to a powerful genome editing tool applied to a multifold species, ranging from bacteria to human. Pgi5Cas13b and Pgi8Cas13b are identified by a computational sequence database mining approach, the CRISPR arrays lack of Cas1 and Cas2 encoding genes but contain a large candidate effector protein around 1,200 amino acids. They can be potentially classified as subtype VI-B CRISPR-Cas systems. We characterized the mature crRNA for Pgi5Cas13b and Pgi8Cas13b via Northern blot and small RNA sequencing. By EMSA (Electrophoretic mobility shift assay) experiments, we identified the binding constant between Pgi5Cas1b/Pgi8Cas13b and their corresponding crRNAs. The CRISPR loci of two of the Cas13b systems were cloned in pACYC vector and expressed in E. coli cells. Small RNAs were extracted and characterized by Northern Blotting and NGS (small RNA-seq) methods. The NGS results revealed the exact sequences of the crRNAs, which show a few new features not previously observed in other systems, including the longest spacer-derived sequences (32 and 31 nt), spacer-derived sequences flanking both ends of the full DR-derived sequence. The results also indicate different rules of pre-crRNA processing by the Pgi5Cas13b and Pgi8Cas13b systems. The characterization of these CRISPR systems extends the application of CRISPR based genome editing tools and promotes the development of single transcript manipulation tools.
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Nickels, Elizabeth Anne. "Structural and thermogravimetric studies of group I and II borohydrides." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:f18f8f7c-1837-4b96-b4bb-5f964e93899c.
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This thesis investigates the structure and thermal behaviour of LiBH4, NaBH4, KBH4, LiK(BH4)2, Ca(BH4)2 and Sr(BH4)2. LiK(BH4)2 is the first mixed alkali metal borohydride and was synthesised and characterised during this work. The crystal structures of these borohydrides were studied using variable temperature neutron and synchrotron X-ray diffraction. The synthesis of isotopically enriched samples of 7Li11BD4, Li11BD4, Na11BD4 and K11BD4 allowed high quality neutron diffraction data to be collected. Particular attention was paid to the exact geometry of the borohydride ions which were generally found to be perfect tetrahedra but with orientational disorder. New structures of Ca(BH4)2 were identified and the first crystal structure of Sr(BH4)2 was determined from synchrotron X-ray diffraction data. Solid state 11B NMR and Raman spectroscopy provided further information about the structure of these borohydrides. The thermal behaviour of the borohydrides was investigated using thermogravimetric analysis with mass spectrometry of the decomposition gas products. Hydrogen is the main decomposition gas product from all of these compounds but small amounts of B2H6 and BH3 were also detected during decomposition. Thermogravimetic analyses of Na11BD4 and K11BD4 were completed whilst collecting in-situ neutron diffraction data allowing information about structural changes and mass losses to be combined in order to better understand the decomposition process.
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Halavaty, Andrei Stepanovich. "The "shuttle" mechanism of the electron transport by the ruthenium(II) bipyridyl complex-modified bovine adrenodoxin in the steroid hydroxylase crystal structure and intramolecular electron transfer /." [S.l.] : [s.n.], 2005. http://www.diss.fu-berlin.de/2005/340/index.html.
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Sturtz, Benjamin Walden. "Synthesis and Structural Chemistry of Diamagnetic Dimeric Metal Phthalocyanines." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1496922051865658.
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Junior, Walter Filgueira de Azevedo. "Determinação da estrutura de alguns complexos de estanho e de platina." Universidade de São Paulo, 1992. http://www.teses.usp.br/teses/disponiveis/54/54132/tde-10032014-173729/.
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Foram determinadas as estruturas de três complexos de Platina, dois complexos de estanho e um ligante orgânico. AS intensidades das reflexões foram medidas com umdifratômetro CAD-4. As estruturas foram resolvidas por métodos diretos ou pela função de Patterson e refinadas por mínimos quadrados. Bis (fenilsulfonil) etano, C14H14(SO2)2, foi obtido durante as tentativas de sintetizar ligantes para serem usados na complexação com diversos organo-estânicos, o cristal pertence ao sistema moniclínico, P21/n, a= 8,495(3), b= 10,159(1), c= 9,072(1)Å, β= 116,23(2) °, V= 702,3(3) ޵, Z= 2, dcalc= 1,467g.cm-3. Cis-dicloro[meso-1,2-bis(n-propilsulfinil)etano]platina(II), PtCl2. (PrSO)2C2H4, o cristal pertence ao sistema ortorrômbico, P212121, a= 7,360(2), b= 9,793(2), c= 19,369(2)Å, V= 1396,1(4)޵, Z= 4, dcalc= 2,25g.cm-3. Trans-diclorol[(trietilfosfina) (2-metilsulfinil)piridina)]platina(II), Et3PPtCl 2.PySOMe, o cristal pertence ao sistema monoclínico, P21/c, a= 8,067(3), b= 8,5184(9), c= 25,592(3)Å, β= 92,000(9)°, V= 1757,6(7)޵, Z= 4, dcalç= 1,98g.cm-3. Trans-dicloro [(trietilfosfina)(2-n-propilsulfinil)piridina)]platina(II), Et3PPtCl2.PySOPr, o cristal pertence ao sistema triclínico, P-1, a= 8,254(3), b= 8,377(4), c= 14,531(4)Å, α= 87,14(3), β= 82,83(3), Υ= 84,10(3)°, V= 991,0(7)޵, Z= 2, dcalc= 1,78g.cm-3. Mer-tricloro [(2-metilsulfinil)benzotiazol)]metilestanho(IV), MeSnCl3.BtSOMe)2, o cristal pertence ao sistema monoclínico, C2/c, a= 20,083(2), b= 17,406(1), c= 14,415(2)Å, β= 108,06(3), V= 4790,5(8)޵, Z= 8, dcalc= 1,78g.cm-3. Hidroxi cloreto de difenil estanho (IV) + mesobis (fenilsulfinil)metano, SnClOHPh2 + Ph2(SO) 2CH2, o cristal pertence ao sistema monoclínico, P21/c, a= 10,540(3), b= 9,743(1), c= 24,099(7)Å, β= 92,95(2), V= 2471(1)޵, Z= 4, dcalç= 1,58g.cm-3<br>The structures of three platinum complexes, two organotin compounds and organic ligand were determined. The reflection intensities were measured with a CAD-4 automatic diffractometer. The structures were solved by direct methods or the Patterson function and were refined by least squares method. Bis (phenylsulfonyl)ethane, C14H14(SO2)2, was obtained among attempts to synthesize ligands to be used for complexation with several organotins, the crystal belongs to the monoclinic system, P21/n, a= 8,495(3), b= 10,159(1), c= 9,072(1)Å, β= 116,23(2) °, V= 702,3(3) ޵, Z= 2, dcalc= 1,467g.cm-3. Cis-dichloro [ meso 1,2-bis(n-propylsulphinyl)ethane]platinum(II), PtCl2. (PrSO)2C2H4 the crystal belongs to the orthorhombic system, P212121, a= 7,360(2), b= 9,793(2), c= 19,369(2)Å, V= 1396,1(4)޵, Z= 4, dcalc= 2,25g.cm-3. Trans-dichloro [(triethylphosphine) (2-methylsulphinyl)pyridine)]platinum(II), Et3PPtCl 2.PySOMe, the crystal belongs to the monoclinic system, P21/c, a= 8,067(3), b= 8,5184(9), c= 25,592(3)Å, β= 92,000(9)°, V= 1757,6(7)޵, Z= 4, dcalç= 1,98g.cm-3. Trans-dichloro [(triethylphosphine) (2-npropylsulphinyl) pyridine)]platinum(II), Et3PPtCl2.PySOPr, the crystal belongs to the orthorhombic system, P-1, a= 8,254(3), b= 8,377(4), c= 14,531(4)Å, α= 87,14(3), β= 82,83(3), Υ= 84,10(3)°, V= 991,0(7)޵, Z= 2, dcalc= 1,78g.cm-3. Mer-trichloro[(2-methylsulphinyl)benzothiazole)]methyltin(IV), MeSnCl3.BtSOMe)2 the crystal belongs to the monoclinic system, C2/c, a= 20,083(2), b= 17,406(1), c= 14,415(2)Å, β= 108,06(3), V= 4790,5(8)޵, Z= 8, dcalc= 1,78g.cm-3. Hidroxe chloride diphenyl tin (IV) + mesobis (phenylsulphinyl)methane, SnClOHPh2 + Ph2(SO) 2CH2 the crystal belongs to the monoclinic system, P21/c, a= 10,540(3), b= 9,743(1), c= 24,099(7)Å, β= 92,95(2), V= 2471(1)޵, Z= 4, dcalç= 1,58g.cm-3
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Manning, Linda. "The crystal structures of xenobiotic reductase A and B from pseudomonas putida II-B and pseudomonas fluorescens I-C: structural insight into regiospecific reactions with nitrocompounds." Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-11232005-155545/.
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Thesis (Ph. D.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2006.<br>Dr. Allen M. Orville, Committee Chair ; Dr. Loren D. Williams, Committee Member ; Dr. Dale E. Edmondson, Committee Member ; Dr. Frank E. Lffler, Committee Member ; Dr. Nicholas V. Hud, Committee Member
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SOUSA, JÚNIOR Joel Padilha de. "Estudo estrutural de complexos de cobre (II) como modelos de sítios metálicos de enzimas com atividade oxidativa." Universidade Federal de Goiás, 2009. http://repositorio.bc.ufg.br/tede/handle/tde/819.
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Previous issue date: 2009-04-24<br>We present the structural study, by x-rays diffraction, of two forms on the crystalline and molecular structures of the metal-organic single-crystal compounds Dicloro[N-
benzoyl-N´-(4-methylphenyl)-N´´-(2-pyridinyl)-guanidine)]copper(II). Such compound is known
for the phenol oxidative catalictic bioactivity. The compound is a copper(II)-guanidine de-
rivative complex. The main motivation of the present work is the polimorphism observed
on such complex when the crystallization conditions are changed. The structures were sol-
ved using the Direct Methods method and the structural parameters were refined with full
matrix least-squares method.
The copper(II) complex C19H22Cl2CuN4O crystallizes in the triclinic system in
the P¯1 space group, with a single molecule in the assymetric unit and unit cell parameters:
a = 8.616 (3) °A, b = 9.288 (3) °A, c = 13.623 (2) °A, α = 106.96 (2)o, β = 96.02 (3)o, γ
= 100.60 (2)o, with volume 1010.3 (5) °A3 and calculated density of 1.528 Mgm−3. The
same compound also crystallizes in the monoclinic system in the P21/n space group and
unit cell parameters: a = 7.937 (2) °A, b = 18.727 (2) °A, c = 13.993 (2) °A, β = 102.03
(2)o, with volume 2034.2 (6) °A3 and calculated density 1.518 Mgm−3. The two isomeric
molecules showed different conformations from one crystal packing to the other, due to the
different intermolecular interactions. Given the different crystal packing and intermolecular
interactions, we performed electronic structure calculations using the Density Functional
Theory in order to derive the energetic differences, including calculations of dimers linked
by hydrogen bonds, for evaluating the crystal packing influence on the complex stability in
their crystal structures.<br>Apresentamos um estudo estrutural, por difra¸c ao de raios X, das estruturas cris-
talinas e moleculares de um composto metalorg anico no estado monocristalino Dicloro [N-
benzoil-N´-(4-metilfenil)-N´´-(2-piridinil)-guanidina)] Cobre(II). O qual apresenta atividade
biol´ogica de cat´alise do processo de oxida¸c ao de fen´ois. O complexo ´e de cobre(II) com um
derivado do grupo qu´ımico org anico guanidina. A motiva¸c ao ao exposto nesta disserta¸c ao foi
a ocorr encia de duas formas polim´orficas do complexo supracitado variando-se as condi¸c oes
de cristaliza¸c ao. As estruturas foram resolvidas utilizando o M´etodo Direto e para o re-
finamento dos par ametros t´ermicos usou-se o m´etodo dos m´ınimos quadrados de matriz
completa.
O complexo de cobre(II) C19H22Cl2CuN4O foi cristalizado no sistema cristalino
tricl´ınico, no grupo espacial P¯1, com uma mol´ecula independente por unidade assim´etrica
e par ametros de cela: a = 8,616 (3) °A, b = 9,288 (3) °A, c = 13,623 (2) °A, α = 106,96
(2)o, β = 96,02 (3)o, γ = 100,60 (2)o com volume de 1010,3 (5) °A3 e a densidade calculada
1,528 Mgm−3. O mesmo composto cristalizou-se no sistema cristalino monocl´ınico, no grupo
espacial P21/n, em que foi observada uma mol´ecula por unidade assim´etrica com par ametros
cela unit´aria: a = 7,937 (2) °A, b = 18,727 (2) °A, c = 13,993 (2) °A, β = 102,03 (2)o, volume
2034,2 (6) °A3, densidade calculada 1,518 Mgm−3. Estruturalmente id enticas as mol´eculas
apresentaram diferentes conforma¸c oes moleculares e seus dois empacotamento apresentaram
intera¸c oes intermoleculares bastante distintas. Em fun¸c ao dos diferentes arranjos cristalinos
e das diferentes intera¸c oes intermoleculares, foram feitos c´alculos de estrutura eletr onica com
a Teoria do Funcional Densidade para inferir as diferen¸cas energ´eticas, incluindo d´ımeros que
interagem por pontes de hidrog enio, com o objetivo de avaliar a influ encia do empacotamento
cristalino na estabilidade do complexo nas estruturas cristalinas.
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Abdulmalic, Mohammad A., Azar Aliabadi, Andreas Petr, et al. "An interplay between the spin density distribution and magnetic superexchange interactions: a case study of mononuclear [nBu4N]2[Cu(opooMe)] and novel asymmetric trinuclear [Cu3(opooMe)(pmdta)2](NO3)2·3MeCN." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-138948.
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Treatment of the diethyl ester of o-phenylenebis(oxamic acid) (opbaH2Et2, 1) with 5/6 equivalent of MeNH2 in abs. EtOH results in the exclusive formation of the ethyl ester of o-phenylene(N′-methyl oxamide)(oxamic acid) (opooH3EtMe, 2) in ca. 50% yield. Treatment of 2 with four equivalents of [Me4N]OH followed by the addition of Cu(ClO4)2·6H2O gave [Me4N]2[Cu(opooMe)]·H2O (3A) in ca. 80% yield. As 3A appears to be a hygroscopic solid, the related [nBu4N]+ salts [nBu4N]2[M(opooMe)]·H2O (M = Cu (3B), Ni (4)) have been synthesized. By addition of two equivalents of [Cu(pmdta)(NO3)2] to a MeCN solution of 3B the novel asymmetric trinuclear complex [Cu3(opooMe)(pmdta)2](NO3)2 (5) could be obtained in ca. 90% yield. Compounds 2, 3A, 3B, 4 and 5 have been characterized by elemental analysis and NMR/IR spectroscopy. Furthermore, the solid state structures of 3A in the form of [Me4N]2[Cu(opooMe)]·MeOH (3A′), 3B in the form of [nBu4N]2[Cu(opooMe)] (3B′), 4 in the form of [nBu4N]2[Ni(opooMe)]·1.25H2O (4′) and 5 in the form of [Cu3(opooMe)(pmdta)2] (NO3)2·3MeCN (5′), respectively, have been determined by single-crystal X-ray diffraction studies. By controlled cocrystallization, diamagnetically diluted 3B (1%) in the host lattice of 4 (99%) in the form of single crystals have been made available, allowing single crystal EPR studies to extract all components of the g-factor and the tensors of onsite CuA and transferred NA hyperfine interaction. Out of these studies the spin density distribution of the [Cu(opooMe)]2− complex fragment could be determined. The magnetic properties of 5 were studied by susceptibility measurements versus temperature. An intramolecular J parameter of −65 cm−1 has been obtained, unexpectedly, as 5 should possess two different J values due to its two different spacers between the adjacent CuII ions, namely an oxamate (C2NO3) and an oxamidate (C2N2O2) fragment. This unexpected result is explained by a summarizing discussion of the experimentally obtained EPR results (spin density distribution) of 3B, the geometries of the terminal [Cu(pmdta)]2+ fragments of 5 determined by X-ray crystallographic studies and accompanying quantum chemical calculations of the spin density distribution of the mononuclear [Cu(opooMe)]2− and of the magnetic exchange interactions of trinuclear [Cu3(opooMe)(pmdta)2]2+ complex fragments<br>Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
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Bette, Sebastian. "Über basische Chloride des Nickel(II) und Magnesiums : Strukturen, Phasenbildung und Löslichkeit." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2016. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-207718.
Full textAbstract:
In der vorliegenden Arbeit wurde die Phasenbildung im ternären System Ni(OH)2-NiCl2-H2O systematisch untersucht. Die basischen Nickel(II)-chlorid Phasen NiCl(OH), Ni2Cl(OH)3, NiClx(OH)2-x, Ni3Cl2+x(OH)4-x ∙ 2 H2O mit x = 0,26; 0,48; 0,82 und Ni3Cl2+x(OH)4-x ∙ 4 H2O mit x = 0,10 konnten phasenrein hergestellt und deren Kristallstrukturen mittels hochauflösender Röntgenpulverdiffraktometrie aufgeklärt werden. Die so erhaltenen strukturellen Daten wurden durch Anwendung von IR-und Spektroskopie, UV/VIS-Spektroskopie, SQUID-Messungen, Thermoanalysen und temperaturaufgelöster in-situ Röntgenpulverdiffraktometrie als komplementäre Methoden bestätigt. Weiterhin konnte eine allgemein anwendbare Routine zur Beschreibung der Diffraktionseffekte stapelfehlerbehafteter Schichtverbindungen für das Programm TOPAS entwickelt werden. Die Bildung und Stabilität der basischen Nickel(II)-chlorid Phasen in wässriger Nickel(II)-chlorid Lösung wurde systematisch bei 200°C und 25°C über Zeiträume von zwei Jahren untersucht und Löslichkeitsdaten ermittelt.
Des Weiteren erfolgte die Untersuchung der Wechselwirkung von Magnesium Oxid und basischen Magnesiumchlorid Phasen mit wässrigen nickelhaltigen Magnesiumchlorid Lösungen. Hierbei konnte die Mischkristallbildung zwischen analogen basischen Magnesium- und Nickel(II)-chloridphasen beobachtet werden. Es wurde festgestellt, dass basische Magnesiumchloride und Magnesiumoxid ein gutes Rückhaltevermögen für gelöstes Nickel aufweisen und dass ein Zutritt von gelöstem Nickel weder die Pufferwirkung noch die Beständigkeit der basischen Magnesiumchlorid Phasen beeinträchtigt.
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Abdulmalic, Mohammad A., Azar Aliabadi, Andreas Petr, et al. "An interplay between the spin density distribution and magnetic superexchange interactions: a case study of mononuclear [nBu4N]2[Cu(opooMe)] and novel asymmetric trinuclear [Cu3(opooMe)(pmdta)2](NO3)2·3MeCN." Royal Society of Chemistry, 2012. https://tud.qucosa.de/id/qucosa%3A27795.
Full textAbstract:
Treatment of the diethyl ester of o-phenylenebis(oxamic acid) (opbaH2Et2, 1) with 5/6 equivalent of MeNH2 in abs. EtOH results in the exclusive formation of the ethyl ester of o-phenylene(N′-methyl oxamide)(oxamic acid) (opooH3EtMe, 2) in ca. 50% yield. Treatment of 2 with four equivalents of [Me4N]OH followed by the addition of Cu(ClO4)2·6H2O gave [Me4N]2[Cu(opooMe)]·H2O (3A) in ca. 80% yield. As 3A appears to be a hygroscopic solid, the related [nBu4N]+ salts [nBu4N]2[M(opooMe)]·H2O (M = Cu (3B), Ni (4)) have been synthesized. By addition of two equivalents of [Cu(pmdta)(NO3)2] to a MeCN solution of 3B the novel asymmetric trinuclear complex [Cu3(opooMe)(pmdta)2](NO3)2 (5) could be obtained in ca. 90% yield. Compounds 2, 3A, 3B, 4 and 5 have been characterized by elemental analysis and NMR/IR spectroscopy. Furthermore, the solid state structures of 3A in the form of [Me4N]2[Cu(opooMe)]·MeOH (3A′), 3B in the form of [nBu4N]2[Cu(opooMe)] (3B′), 4 in the form of [nBu4N]2[Ni(opooMe)]·1.25H2O (4′) and 5 in the form of [Cu3(opooMe)(pmdta)2] (NO3)2·3MeCN (5′), respectively, have been determined by single-crystal X-ray diffraction studies. By controlled cocrystallization, diamagnetically diluted 3B (1%) in the host lattice of 4 (99%) in the form of single crystals have been made available, allowing single crystal EPR studies to extract all components of the g-factor and the tensors of onsite CuA and transferred NA hyperfine interaction. Out of these studies the spin density distribution of the [Cu(opooMe)]2− complex fragment could be determined. The magnetic properties of 5 were studied by susceptibility measurements versus temperature. An intramolecular J parameter of −65 cm−1 has been obtained, unexpectedly, as 5 should possess two different J values due to its two different spacers between the adjacent CuII ions, namely an oxamate (C2NO3) and an oxamidate (C2N2O2) fragment. This unexpected result is explained by a summarizing discussion of the experimentally obtained EPR results (spin density distribution) of 3B, the geometries of the terminal [Cu(pmdta)]2+ fragments of 5 determined by X-ray crystallographic studies and accompanying quantum chemical calculations of the spin density distribution of the mononuclear [Cu(opooMe)]2− and of the magnetic exchange interactions of trinuclear [Cu3(opooMe)(pmdta)2]2+ complex fragments.<br>Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
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Petit, Samuel. "Structures de complexes dans le système (cuivre (II)-oxine-sulfoxine-eau), étude expérimentale et modélisation moléculaire de la cristallisation et de transitions de phases." Rouen, 1994. http://www.theses.fr/1994ROUES025.
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La résolution structurale d'une nouvelle variété anhydre d'oxinate de cuivre(II) (noté X) a été effectuée d'après le diagramme de diffraction X sur poudre. L'étude des filiations structurales et la prise en compte des données cinétiques, thermodynamiques et physico-chimiques ont mené à proposer un modèle pour les transitions solide-solide entre variétés dihydratées et anhydres d'oxinate de cuivre(II) (déshydratations et transitions polymorphiques). La résolution de structure sur monocristal et sur poudre de deux variétés hydratées de sulfoxinate de cuivre(II) a permis une étude par modélisation moléculaire de la nucléation homogène en solution aqueuse des variétés de structure connue. La croissance cristalline des sulfoxinates de cuivre(II) a été envisagée, conduisant à considérer la croissance d'une face associée à une tranche contenant deux molécules de conformations différentes. Le concept de sous-tranches non équivalentes par les opérations de symétrie du groupe d'espace est défini. Deux approches complémentaires ont été utilisées en vue d'expliquer l'influence de la sulfoxine sur l'évolution des oxinates de cuivre(II). D'une part, une étude des molécules d'oxine et de sulfoxine par les méthodes de chimie théorique a permis d'interpréter leur comportement en milieu aqueux. D'autre part, une étude expérimentale des complexes mixtes cuivre-oxine-sulfoxine a été entreprise
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Baron, Thierry. "Dopage des semiconducteurs II-VI à base de tellure et réalisation de structures quantiques." Université Joseph Fourier (Grenoble ; 1971-2015), 1996. http://www.theses.fr/1996GRE10060.
Full textAbstract:
Nous avons etudie le dopage des semiconducteurs ii-vi a base de tellure. Concernant le dopage de type n, nous avons montre que l'impurete iode est mieux adaptee que l'impurete indium, pour atteindre de fortes concentrations de porteurs dans cdte et cdznte. Le dopage de type p est realise en utilisant une cellule dc plasma, permettant d'obtenir de l'azote sous forme atomique. En comparant les proprietes electriques, optiques et structurales de znte:n et de cdte:n, nous avons mis en evidence un phenomene de compensation limitant le niveau maximum de dopage accessible pour cdte:n. Afin de comprendre l'origine de ce phenomene, nous avons entrepris l'etude du dopage des alliages cdznte et des alliages cdmgte et znmgte. A partir de cette etude, nous avons elabore un modele fonde sur la comparaison des enthalpies de formation des composes nitrures a#3n#2 (a=cd, zn, mg). La formation de tels composes limiterait la solubilite limite de l'azote en site substitutionnel actif. Ainsi, la compensation interviendrait preferentiellement dans les materiaux contenant du mg puis du cd, et serait faible pour le materiau znte. Un mecanisme complementaire, faisant intervenir le parametre de maille, a egalement ete propose. Maitrisant le dopage des tellurures, nous avons realise des heterostructures dopees par modulation afin d'etudier des gaz d'electrons bidimensionnels. En epitaxiant des puits quantiques dopes de type p, nous avons montre que la localisation de l'impurete azote dans la structure modifie les energies de liaison (i) de l'exciton lie sur un accepteur neutre et (ii) de l'accepteur. Nous avons mis en evidence, par des mesures optiques, structurales et chimiques, une acceleration de l'interdiffusion dans les superreseaux contenant a la fois du mg et de l'azote. Enfin, nous avons realise des dispositifs optoelectroniques tels que des modulateurs optiques ou des emetteurs et des detecteurs de rayonnement dans l'infrarouge
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Chaignon, Jérémy. "Materials for depollution based on the model of manganese dioxygenases." Thesis, Lyon, École normale supérieure, 2013. http://www.theses.fr/2013ENSL0877/document.
Full textAbstract:
L'objectif de cette thèse est la synthèse d'un matériau modèle de la dioxygénase à manganèse, une enzyme oxydant des cycles aromatiques type catéchol grâce au dioxygène. Pour ce faire, nous avons découpé notre stratégie trois étapes constituant les différents chapitres de ce manuscrit : - La synthèse et la caractérisation des complexes de manganèse(II) avec des ligands tridentates. - L'optimisation d'une synthèse de silice mésoporeuse par micro-onde. - La fonctionnalisation des matériaux et le greffage des complexes, ainsi que les tests catalytiques préliminaires.Les ligands utilisés sont des amines tertiaires avec un bras alcyne et deux coordinants type pyridine, imidazole ou carboxylate. Ces complexes ont été cristallisés et/ou caractérisés par IR, RPE, SQUID et voltampérométrie cyclique. La synthèse par micro-onde, basée sur des conditions de synthèse hydrothermale classiquenous a permis de réduire le temps de synthèse d'un jour à deux heures. La qualité de ces nouveaux matériaux a été vérifiée par IR, ATG, BET, et DRX sur poudre. Ces matériaux sont ensuite bifonctionnalisés en utilisant une méthode de pochoir moléculaire avec une fonction azoture pour le greffage du complexe via "click-chemistry" ainsi qu'une fonction pyridine ou triméthylsilyle pour créer un environnement coordinant ou non proche du métal.Ces complexes et matériaux sont actifs dans l'oxydation du catéchol<br>The objective of this work is the synthesis of model material for manganese dioxygenase which is an enzyme that oxidizes catechol-like substrates with dioxygen. Our strategy comprises three main steps that form the different chapters of this thesis: - Synthesis and characterization of manganese(II) complexes with tridentate ligands. - Optimization of a microwave-assisted synthesis of a mesoporous silica. - Functionalization of these materials and complex grafting, as well as preliminary catalytic tests. The ligands used are tertiary amines containing an alkyne arm and two coordinating arms with functions such as pyridine, imidazole or carboxylate. The complexes were crystallized and/or characterized by IR, EPR, SQUID and cyclic voltamperometry. Microwave synthesis, based on the conditions of classical hydrothermal synthesis, allowed us to reduce the synthesis time from one day to two hours. The quality of these new materials was verified by IR, TGA, BET and powder XRD. These materials are then bi-functionalized using a molecular stencil patterning mehod with a an azide function for complex grafting via click chemistry and a function pyridine or trimethylsilyl to control the coordinating ability of the metal environment. These complexes and materials are active in catechol oxidation with O2
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Chaignon, Jérémy, and Jérémy Chaignon. "Materials for depollution based on the model of manganese dioxygenases." Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2013. http://tel.archives-ouvertes.fr/tel-01015623.
Full textAbstract:
The objective of this work is the synthesis of model material for manganese dioxygenase which is an enzyme that oxidizes catechol-like substrates with dioxygen. Our strategy comprises three main steps that form the different chapters of this thesis: - Synthesis and characterization of manganese(II) complexes with tridentate ligands. - Optimization of a microwave-assisted synthesis of a mesoporous silica. - Functionalization of these materials and complex grafting, as well as preliminary catalytic tests. The ligands used are tertiary amines containing an alkyne arm and two coordinating arms with functions such as pyridine, imidazole or carboxylate. The complexes were crystallized and/or characterized by IR, EPR, SQUID and cyclic voltamperometry. Microwave synthesis, based on the conditions of classical hydrothermal synthesis, allowed us to reduce the synthesis time from one day to two hours. The quality of these new materials was verified by IR, TGA, BET and powder XRD. These materials are then bi-functionalized using a molecular stencil patterning mehod with a an azide function for complex grafting via click chemistry and a function pyridine or trimethylsilyl to control the coordinating ability of the metal environment. These complexes and materials are active in catechol oxidation with O2.
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Guergouri, Kamel. "Etude des defauts cristallins et des proprietes physiques associees dans cdte et ses alliages avec znte, mnte." Paris 6, 1987. http://www.theses.fr/1987PA066412.
Full textAbstract:
Etude de l'amelioration de cdte dans le cadre de la recherche de semiconducteurs de bonne qualite cristalline. Le premier parametre necessaire a cette amelioration et celui de la substitution de cd par zn (impurete isoelectronique et permet la reduction de la densite de dislocations d'un facteur 10. Proposition d'un modele de durcissement d'alliage pour expliquer ce phenomene. Le 2eme parametre concerne la recherche des conditions de croissance optimales
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Calamba, Katherine. "Phase stability and defect structures in (Ti1-x,Alx)Ny hard coatings." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0322.
Full textAbstract:
Cette étude met en évidence le rôle des lacunes d’azote et des défauts structuraux dans l’ingénierie de revêtements durs à stabilité de phase améliorée et dont les propriétés mécaniques sont compatibles avec des applications à haute température. Le nitrure de titane et d’aluminium (Ti,Al)N sous forme de revêtements est un matériau de choix pour la protection des outils de coupe pour métaux en raison de sa résistance supérieure à l’oxydation et à l’usure à haute température. La décomposition spinodale à haute température de la phase métastable cubique (Ti,Al)N en domaines cohérents de taille nanométrique de c-TiN et de c-AlN donne une dureté importante aux températures élevées. Un apport thermique encore plus élevé conduit à la transformation de c-AlN en w-AlN, ce qui nuit aux propriétés mécaniques du revêtement. Un moyen de retarder cette transformation est d'introduire des lacunes d'azote. Dans cette thèse, je montre que la combinaison d’une réduction de la teneur globale en azote du revêtement c-(Ti,Al)Ny(y <1) avec une faible tension de polarisation du substrat lors du dépôt par arc cathodique induit un retard encore plus prononcé de la transformation de la phase c-AlN en w-AlN. Dans de telles conditions, le durcissement par vieillissement est conservé jusqu'à 1100 ° C, ce qui correspond à la température la plus élevée signalée pour les films de (Ti,Al)N. Au cours des opérations de coupe, le mécanisme d'usure des films c-(Ti0.52Al0.48)Ny déposés par arc cathodique avec des teneurs en N de y = 0.92, 0.87 et 0.75 est influencé par l'interaction des lacunes d'azote, de la microstructure et des réactions chimiques avec le matériau de la pièce. Le revêtement y = 0.75 contient le plus grand nombre de macroparticules et présente, après usinage, une microstructure non homogène qui en abaisse la résistance à l'usure sur les flancs et les cratères. Le durcissement par vieillissement de l'échantillon y = 0.92 entraîne une résistance supérieure à l'usure sur le flanc, tandis que la structure dense de l'échantillon y = 0.87 empêche l'usure chimique qui se traduit par une excellente résistance à l'usure sur les cratères. Des films hétéroépitaxiés c-(Ti1-x, Alx)Ny (y = 0.92, 0.79 et 0.67) ont été déposés sur des substrats de MgO(001) et (111) en utilisant une technique de pulvérisation magnétron pour examiner en détail les défauts structuraux pendant la décomposition spinodale. À 900 °C, les films se décomposent pour former des domaines cohérents riches en c-AlN et c-TiN de forme allongée le long de la direction <001>. Les cartographies de déformation montrent que la plupart des contraintes se trouvent près de l'interface des domaines ségrégés et à l'intérieur des domaines c-TiN. Les dislocations s'agrègent favorablement dans c-TiN plutôt que dans c-AlN car ce dernier a une directionnalité plus forte des liaisons chimiques covalentes. À température élevée, la taille de domaine des films de c- (Ti, Al)Ny orientés (001) et (111) augmente avec la teneur en azote. Cela indique qu'il y a un retard dans le grossissement dû à la présence de plus de lacunes d’azote dans le film. [...]<br>This study highlights the role of nitrogen vacancies and defect structures in engineering hard coatings with enhanced phase stability and mechanical properties for high temperature applications. Titanium aluminum nitride (Ti,Al)N based materials in the form of thin coatings has remained as an outstanding choice for protection of metal cutting tools due to its superior oxidation resistance and high-temperature wear resistance. High-temperature spinodal decomposition of metastable (Ti,Al)N into coherent c-TiN and c-AlN nm-sized domains results in high hardness at elevated temperatures. Even higher thermal input leads to transformation of c-AlN to w-AlN, which is detrimental to the mechanical properties of the coating. One mean to delay this transformation is to introduce nitrogen vacancies. In this thesis, I show that by combining a reduction of the overall N-content of the c-(Ti,Al)Ny (y < 1) coating with a low substrate bias voltage during cathodic arc deposition an even more pronounced delay of the c-AlN to w-AlN phase transformation is achieved. Under such condition, age hardening is retained until 1100 °C, which is the highest temperature reported for (Ti,Al)N films. During cutting operations, the wear mechanism of the cathodic-arc-deposited c-(Ti0.52Al0.48)Ny with N-contents of y = 0.92, 0.87, and 0.75 films are influenced by the interplay of nitrogen vacancies, microstructure, and chemical reactions with the workpiece material. The y = 0.75 coating contains the highest number of macroparticles and has an inhomogeneous microstructure after machining, which lower its flank and crater wear resistance. Age hardening of the y = 0.92 sample causes its superior flank wear resistance while the dense structure of the y = 0.87 sample prevents chemical wear that results in excellent crater wear resistance. Heteroepitaxial c-(Ti1-x,Alx)Ny (y = 0.92, 0.79, and0.67) films were grown on MgO(001) and (111) substrates using magnetron putter deposition to examine the details of their defect structures during spinodal decomposition. At 900 °C, the films decompose to form coherent c-AlN- and c-TiN- rich domains with elongated shape along the elastically soft <001> direction. Deformation maps show that most strains occur near the interface of the segregated domains and inside the c-TiN domains. Dislocations favorably aggregate in c-TiN rather than c-AlN because the later has stronger directionality of covalent chemical bonds. At elevated temperature, the domain size of (001) and (111)- oriented c-(Ti,Al)Ny films increases with the nitrogen content. This indicates that there is a delay in coarsening due to the presence of more N vacancies in the film. The structural and functional properties (Ti1-x,Alx)Ny are also influenced by its Al content (x). TiN and (Ti1-x,Alx)Ny (y = 1, x = 0.63 and x = 0.77) thin films were grown on MgO(111) substrates using magnetron sputtering technique. Both TiN and Ti0.27Al0.63N films are single crystals with cubic structure. (Ti0.23,Al0.77)N film has epitaxial cubic structure only in the first few atomic layers then it transitions to an epitaxial wurtzite layer, with an orientation relationship of c-(Ti0.23,Al0.77)N(111)[1-10]ǀǀw-(Ti0.23,Al0.77)N(0001)[11-20]. The w-(Ti0.23,Al0.77)N shows phase separation of coherent nm-sized domains with varying chemical composition during growth. After annealing at high temperature, the domains in w-(Ti0.23,Al0.77)N have coarsened. The domains in w-(Ti0.23,Al0.77)N are smaller compared to the domains in c-(Ti0.27,Al0.63)N film that has undergone spinodal decomposition. The results that emerged from this thesis are of great importance in the cutting tool industry and also in the microelectronics industry, because the layers examined have properties that are well suited for diffusion barriers
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Yong, Chaw Keong. "Ultrafast carrier dynamics in organic-inorganic semiconductor nanostructures." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:b2efdc6a-1531-4d3f-8af1-e3094747434c.
Full textAbstract:
This thesis is concerned with the influence of nanoscale boundaries and interfaces upon the electronic processes that occur within the inorganic semiconductors. Inorganic semiconductor nanowires and their blends with semiconducting polymers have been investigated using state-of-the-art ultrafast optical techniques to provide information on the sub-picosecond to nanosecond photoexcitation dynamics in these systems. Chapters 1 and 2 introduce the theory and background behind the work and present a literature review of previous work utilising nanowires in hybrid organic photovoltaic devices, revealing the performances to date. The experimental methods used during the thesis are detailed in Chapter 3. Chapter 4 describes the crucial roles of surface passivation on the ultrafast dynamics of exciton formation in gallium arsenide (GaAs) nanowires. By passivating the surface states of nanowires, exciton formation via the bimolecular conversion of electron-hole plasma can observed over few hundred picoseconds, in-contrast to the fast carrier trapping in 10 ps observed in the uncoated nanowires. Chapter 5 presents a novel method to passivate the surface-states of GaAs nanowires using semiconducting polymer. The carrier lifetime in the nanowires can be strongly enhanced when the ionization potential of the overcoated semiconducting polymer is smaller than the work function of the nanowires and the surface native oxide layers of nanowires are removed. Finally, Chapter 6 shows that the carrier cooling in the type-II wurtzite-zincblend InP nanowires is reduced by order-of magnitude during the spatial charge-transfer across the type-II heterojunction. The works decribed in this thesis reveals the crucial role of surface-states and bulk defects on the carrier dynamics of semiconductor nanowires. In-addition, a novel approach to passivate the surface defect states of nanowires using semiconducting polymers was developed.
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Liao, Chen-Hui, and 廖真惠. "Synthesis, Crystal structure and properties of Tin Silicates and Germanate." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/62376458690609679334.
Full textAbstract:
碩士<br>國立中央大學<br>化學研究所<br>94<br>Four new Metal silicates and Metal germanates, [Na3F][SnSi3O9](1)、Cs2SnSi6O15(2)、Cs2SnSi3O9 (3)、Na4Sn2Ge5O16 (4) have been synthesized using a flux-growth method and characterized by single-crystal X-ray diffraction. The structure of 1 consists of 6-membered silicate rings linked via corner-sharing by SnIVO6 octahedra to form a 3-D framework that delimits two types of channels. The F atoms and Na atoms are located in the structural channels and form a dimer with the anti-Al2Cl6(g) structure. This stannosilicate adopts a new structure and is the first metal silicate that contains both Na+ and F- ions in the channels. The 19F and 29Si MAS NMR and 23Na MQMAS NMR spectra are consistent with the crystallographic results. Crystal data: [Na3F][SnSi3O9], monoclinic, space group C2/m (No. 12), a = 10.539(1) Å, b = 13.953(2) Å, c = 6.5171(7) Å, �� = 111.576(2)º, V = 891.2(3) Å3, and Z = 4. The structure of 2 can be expressed in terms of Si6O156- silicate sheets by isolated SnO6 octahedra. The structure of 3 consists of unbranched infinite chain, periodically repeating unit every six tetrahedral. These chains are linked by SnIVO6 octahedra. The structure of 4 is based on [Ge5O16] ( fivefold germanate tetrahedra) that are connected by SnIVO6 octahedra to form 3-D framework. The structure consists of two types of six-membered rings and forms the intersection tunnels.
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Peixoto, Miguel Angelo da Rocha. "Microporous tin silicates: synthesis, crystal structure, ion exchange, isomorphic substitution and thermal properties." Master's thesis, 2013. http://hdl.handle.net/1822/37867.
Full textAbstract:
Dissertação de mestrado integrado em Engenharia de Materiais<br>The present work introduces the transparent precursor as a new media for synthesis of
tin silicates. Based on this approach a systematic work exploiting the potential for formation of
various tin silicates and process optimization of the existing ones has been carried out. The
conducted syntheses resulted in the creation of crystallization fields showing the dependence of
the run product on initial molar composition. Within various synthesis compositions the typical
structures of the sodium based silicate (AV-10) the potassium based tin silicate (AV-6) the sodium
and potassium based tin silicate (AV-7) has been achieved. Another novelty is the fine control of
the crystalline product by the time of agitation of the initial transparent precursor. This type of
phase control has never been studied in tin silicates.
The close structural and synthesis relation between the microporous phases AV-6 and
AV-7 has been studied. The studies on the time of precursor agitation revealed that the transition
between these two structures is time dependent and that AV-7 can be produced in absence of
sodium ions. In the course of creation of the crystallization fields a new potassium tin silicate with
layered structure was prepared. The structure was successfully indexed and the structural
determination is in progress. Ion exchange properties of AV-6 and AV-7 were also explored. AV-6
was exchanged to copper and zinc forms and for the first time it has been revealed the ion
exchange potential of AV-7. The phase was successfully converted into copper, zinc, chromium
and lead forms. It was also seen that upon ion exchanged with divalent ions and coordination
number 8, AV-7, changes differently depending on the captured ion. This behavior may serve to
identify and confirm exchanges in multi ions solutions.
Isomorphous substitutions produced no effects on the synthesized phases. However, the
presence of amorphous germanium in the initial batch of AV-7 resulted in decreased thermal
stability and lower temperature transformation of the AV-7 framework into the Sn-AV-11 phase.
In other thermal studies it was seen that amorphous stannosilicate compositions turn
into cassiterite upon high temperature exposure. The same transformation was seen in Cu-AV-6
that totally degrades after 700ºC and recrystallizes into cassiterite (SnO2) at 750ºC. The thermal
studies also showed the high temperatures transformations of the new layered potassium tin
silicate into Sn-AV-11 and Sn-wadeite. In the ion exchanged forms of AV-7 it was seen that the Zn-
AV-7 gained a thermal stability higher than any other exchanged form and possibly higher than
the unchanged AV-7.<br>Este trabalho introduz um método que utiliza soluções transparentes como nova fonte
para a síntese hidrotérmica de silicatos de estanho. Baseado nesta nova forma, este trabalho
explora o potencial deste novo método para a produção de várias fases cristalinas e para o
aperfeiçoamento das fases já conhecidas. As sínteses realizadas resultaram na criação de
campos de cristalização que indicam a dependência na composição molar inicial no produto
final. Com diferentes composições foi possível sintetizar estruturas de silicatos de estanho
baseadas em sódio (AV-10), em potássio (AV-6 e baseadas em sódio e potássio (AV-7). Outra
novidade foi o controlo do produto final pela manipulação do tempo de agitação do precursor.
Este parâmetro nunca tinha sido estudado para silicatos de estanho.
Também foram estudadas as semelhanças na síntese e na estrutura entre os materiais
AV-6 e AV-7. O estudo da variação do tempo de agitação do percursor mostrou que é possível
fazer a transição entre estas duas estruturas. Graças a este estudo, a estrutura AV-7 foi
produzida pela primeira vez sem iões de sódio. Enquanto foram criados os campos de
cristalização foi produzida uma forma lamelar de silicatos de estanho. Esta fase foi identificada e
reproduzida com sucesso e o processo de caracterização estrutural ainda é alvo de estudo.
Algumas trocas iónicas também foram exploradas nas estruturas AV-6 e AV-7. Para AV-6 foi
possível produzir uma forma com iões de cobre e uma forma com iões de zinco. Foi também
possível, e pela primeira vez, produzir diferentes formas AV-7. Através de troca iónica foi possível
introduzir nesta estrutura iões de cobre, zinco, crómio e chumbo. Para além disso foi encontrado
um comportamento característico na estrutura quando é trocada com iões de carga 2+ e
coordenação 8. Cada ião capturado produz uma alteração característica, isto pode facilitar na
identificação do ião de captura em soluções multi-iões. As substituições isomórficas não
produziram nenhum tipo de alteração às estruturas sintetizadas. No entanto, a presença de
óxido de germânio amorfo no material AV-7 fez com que a sua estabilidade térmica baixasse e a
transformação para Sn-AV-11 acontecesse mais cedo. Outros estudos térmicos revelaram que os
silicatos de estanho amorfos quando expostos a alta temperatura se transformam em cassiterite.
Essa mesma transformação foi vista para Cu-AV-6 que depois de degradação térmica recristaliza
em cassiterite de tamanho nano. Os estudos térmicos também revelaram que a estrutura
lamelar (UM-1) aqui produzida transforma-se em Sn-AV-11, e após contínua exposição ao calor
começa-se a transformar em Sn-Wadeite.
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Cheng, Jack, and 鄭聖騫. "I. Crystal Structure Determination of nine imidazole compounds; II. Crystal Structure Determination of Agglutinin from Abrus precatorius." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/57397607254742780375.
Full textAbstract:
博士<br>國立清華大學<br>物理學系<br>97<br>In the first part, nine crystal structures of imidazole compounds have been determined by X-ray crystallography. Their coordination geometry and crystal packing are described. This part of work helped the author to be accustomed to crystallography. In the second part, the structure of agglutinin from Abrus precatorius has been determined by X-ray crystallography. The structure and the activity as a ribosome-inactivating protein (RIP) have been compared with abrin-a from Abrus precatorius. With docking study, ASN200 of abrin-a was found to be hydrogen bonded with G4323 of 28SRNA, while corresponding PRO199 of agglutinin is a non-polar residue. This may explain the lower toxicity of agglutinin than abrin-a, despite of similarity in secondary structure and the activity cleft of two RIPs.
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Shui, Wei-Ze, and 徐瑋擇. "The Crystal Structure Determination of Metal(II) Complexes and The Crystal Growth of Protein." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/94036086937973182836.
Full textAbstract:
碩士<br>國立交通大學<br>物理研究所<br>86<br>This paper includes two parts. One is to determine the structure
of the single crystal of four Metal(Ⅱ) Complexes by X-ray
diffraction. The other is the method and process in the crystal
growth for the protein of CardiotoxinⅣ First: The four crystals
were provided by Prof. Chung-Sun Chung in the Chemistry
Department of NTHU. We determined the structure of the 4 single
crystals by X-ray diffraction. Of the four complexes, copper(Ⅱ)
ion is five coordinated with geometry of distorted trigonal
bipyramid structure in the first crystal. Copper(Ⅱ) ion has six
coordinations with distorted square bipyramid in the second
crystal. In the third, nickel(Ⅱ) ion has six coordinations with
four N atoms equatorial and N atoms of the isothiocyanate groups
axial, the same geometry as the second crystal. Nickel(Ⅱ) ion
is four-coordinate with four nitrogen atoms in the macrocyclic
plane in the last crystal.Second: The purified material of
CardiotoxinⅣwas provided by Prof. C.C. Yang in the Department
of Life Science of NTHU. We used hanging drop of vapor diffusion
method to grow protein of crystal. We tried to screen the best
condition for the crystallization of CadiotoxinⅣ from 48
conditions.
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Wang, Yi Chi, and 王羿棋. "Crystal structure and enzyme kinetics of Drosophila melanogaster Glutamine synthetase II." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/07039413791505913514.
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Yeh, Shih-Fang, and 葉蒔芳. "In situ Hydrothermal Syntheses, Crystal Structure, and Properties of a Novel Zinc(II) Tetrazolate Coordination Polymers." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/90623425344773288800.
Full textAbstract:
碩士<br>國立臺灣海洋大學<br>生物科技研究所<br>95<br>The [2+3] cycloaddition reactions of cyano with NaN3 through “the in situ ligand hydrothermal syntheses system” afford the ZnN3[5-(3-pyridyl)tetrazolato]; ZnN3(3-ptz). This compound is a 3D networks crystal which contains the tetrazole functional group. By the X-ray diffraction analysis, the crystal crystallizes in the monoclinic system, space group C2/c, with a = 20.4737(5) Å, b = 7.7035(2) Å, c = 14.6938(4) Å, β = 130.0540(10)°. This is a novel crystal structure, we will study the properties of physical and biological.
The tetrazole functional group has found a wide range of application in many area. In medicinal chemistry as a bioisoteres for a carboxylic acid group, bioisosteres are substituents or groups with similar physical or chemical properties that impart similar biological properties to a chemical compound. Compare the toxicity of bioisoteres and similar compound with ZnN3(3-ptz).
We find that ZnN3(3-ptz) and bis(nicotiato)zinc all have cell toxicity in cell and bacteria. The gram-positive bacteria is more significant in the antibacterial effect, the gram-negative bacteria, mainly attributes to the bilayer of cell membrane in gram-negative bacteria, cause limiting the passage of small molecules across the outer barrier.
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Hachikubo, Akihiro, Hirotoshi Sakagami, Hirotsugu Minami, et al. "FORMATION PROCESS OF STRUCTURE I AND II GAS HYDRATES DISCOVERED IN KUKUY, LAKE BAIKAL." 2008. http://hdl.handle.net/2429/2692.
Full textAbstract:
Structure I and II gas hydrates were observed in the same sediment cores of a mud volcano in the
Kukuy Canyon, Lake Baikal. The sII gas hydrate contained about 13-15% of ethane, whereas the
sI gas hydrate contained about 1-5% of ethane and placed beneath the sII gas hydrate. We
measured isotopic composition of dissociation gas from both type gas hydrates and dissolved gas
in pore water. We found that ethane δD of sI gas hydrate (from -196 to -211 ‰) was larger than
that of sII (from -215 to -220 ‰), whereas methane δ13C, methane δD and ethane δD in both
hydrate structures were almost the same. δ13C of methane and ethane in gas hydrate seemed
several permil smaller than those in pore water. These results support the following idea that the
current gas in pore water is not the source of these gas hydrates of both structures. Isotopic data
also provide useful information how the “double structure” gas hydrates formed.
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Maurer, Joshua Ahab. "I. Structure-Function Analysis of the Mechanosensitive Channel of Large Conductance. II. Design of Novel Magnetic Materials using Crystal Engineering." Thesis, 2003. https://thesis.library.caltech.edu/4188/11/Thesis.pdf.
Full textAbstract:
<p>The work presented here encompasses two distinct areas, with the first section addressing structure-function relationships in the mechanosensitive channel of large conductance (MscL) from bacteria. A high-throughput fluorescent screening technique has been developed for the E. coli homologue of MscL. This technique has been applied to a large library of random E. coli MscL mutations to provide insights into channel function. Additionally, attempts have been made to characterize the functionally important regions of MscL and comparisons have been made between the E. coli and M. tuberculosis homologues of MscL.</p>
<p>The second section addresses the design of novel magnetic materials. The guanidinium sulfonate "Ward lattice" from crystal engineering has been used to develop a new family of frustrated magnetic materials.</p>
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Chi-LinWang and 王期麟. "The Study on Crystal Structure Design and the Properties of Cadmium(II) Complexes with Benzoic Acid Series and Nitrogen heterocycles." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/40929783529440252663.
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Geierstanger, Bernhard H. "Base specific binding of copper (II) to Z-DNA : 1.3 A single crystal structure of d(m⁵CGUAm⁵CG) soaked with CuCl₂." Thesis, 1990. http://hdl.handle.net/1957/38128.
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Huang, Chia-Ying, and 黃佳瑩. "Crystal structure of Staphylococcus aureus membrane-bound transglycosylase in complex with a lipid II analog and elucidation of the mechanism of peptidoglycan synthesis." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/05338663118907174645.
Full textAbstract:
博士<br>國立陽明大學<br>微生物及免疫學研究所<br>100<br>Bacterial transpeptidase and transglycosylase on the cell surface are essential for cell wall synthesis and many antibiotics have been developed to target the transpeptidase, but the problem of antibiotic resistance has arisen and caused a major threat in bacterial infection. The transglycosylase has been considered to be another excellent target, but no antibiotics have been developed to target this enzyme. In this study, we first characterize the function of the transmembrane helix and the UvrB domain 2 homolog domain by complementary activity assay and isothermal titration calorimetry. Results show that both are crucial for the transglycosylase activity. Then, we determined the crystal structure of the Staphylococcus aureus membrane-bound transglycosylase, monofunctional glycosyltransferase (MGT), in complex with a lipid II analog to 2.3 angstrom resolution. Results showed that the lipid II-contacting residues are not only conserved in both wild type and drug-resistant bacteria, but also significant in enzymatic activity. Mechanistically, we proposed that K140 and R148 in the glycosyl donor site, instead of the previously proposed E156, are used to stabilize the pyrophosphate-leaving group of lipid II and E100 in the glycosyl acceptor site acts as general base for the 4-OH of GlcNAc to facilitate the transglycosylation reaction. This mechanism, further supported by mutagenesis study and the structure of MGT in complex with moenomycin in the glycosyl donor site, provides a new direction for antibacterial drugs design. Moreover, with the comprehensive crystal structures of S. aureus MGT complex and well characterization of transmembrane helix, we propose a new mechanism for the peptidolgycan synthesis.
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Halavaty, Andrei S. [Verfasser]. "The "shuttle" mechanism of the electron transport by the ruthenium(II) bipyridyl complex-modified bovine adrenodoxin in the steroid hydroxylase : crystal structure and intramolecular electron transfer / Andrei S. Halavaty." 2005. http://d-nb.info/978069064/34.
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Sobha, K. C. "Studies On Phosphate Glasses With Nasicon-Type Chemistry." Thesis, 1995. http://etd.iisc.ernet.in/handle/2005/2093.
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Chien-chang, Tseng, and 曾建璋. "Part I. Crystal Structure of Cytotoxic RC-RNase3 from Rana catesbeiana in Complex with Heparin Part II. Crystallization and Preliminary X-ray Diffraction Analysis of Muscarinic Toxin-Like Proteins,BM14 and BM8 from Bungarus multicinctus." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/00852193855937445814.
Full textAbstract:
碩士<br>國立清華大學<br>生命科學系<br>92<br>Crystal Structure of Cytotoxic RC-RNase3 from
Rana catesbeiana in Complex with Heparin
Abstract
The Rana catesbeiana (bullfrog) ribonucleases, which belong to the RNase A superfamily, exert cytotoxicity and lectin activity. RC-RNase3 has a unique base preference for pyrimidine-guanine rather than pyrimidine-adenine in RNase A. The crystal structure of RC-RNase3 in complex with heparin disaccharide was determined to resolution of 1.6Å. Heparin is one type of glycosaminoglycan locating primarily on the surface of cells or in the extra-cellular matrix. The overall structure of RC-RNase3-heparin complex consists of seven β-strands and three α-helices that present a bowl shape. Heparin was found locating between sheet 1 (β1, β2, β4, and β5) and sheet 2 (β3, β6, and β7). One of the sulfate groups in heparin takes place in a very close position to the free sulfate in the retro binding RC-RNase6 and d(CpG) complex. More interestingly, two sulfate groups in heparin are close to the phosphate groups of d(ApCpGpA) in the catalytic binding RC-RNase and d(ApCpGpA) complex. Our results indicate a new binding mode where heparin sharing approximately the same binding site to the catalytic and retro binding modes.
Crystallization and Preliminary X-ray Diffraction Analysis of Muscarinic Toxin-Like Protein,
BM14 and BM8 from Bungarus multicinctus
Abstract
Two novel proteins BM14 and BM8 were isolated from Bungarus multicinctus (Taiwan banded krait) venom. BM14 and BM8 are sequence identical except Lys37-Lys38 in BM14 and Glu37-Ala38 in BM8. In contrast to BM8, BM14 exhibited an activity on binding to the M2 muscarinic acetlycholine (mAchR) receptor subtype, indicating Lys37 and Lys38 of BM14 play the crucial roles on binding to M2 mAchR. Although BM14 and BM8 shared a 20-38% sequence identity with snake venom cardiotoxins, they did not show the cytotoxicity. Eight out of ten Cys residues in BM14 and BM8 are located at the conserved positions as those in neurotoxin, cardiotoxin and muscarinic toxin protein sequences, so called the three-finger protein. BM14 and BM8 crystals were grown by the hanging drop vapor diffusion method. The crystals of BM14 diffract to 3.0Å and belong to the tetragonal space group I422 with unit-cell parameters a=81.68Å, b=81.68Å, c=207.30Å, and α=β=γ=90°. The crystals of BM8 diffract to 3.8 Å and belong to the hexagonal space group with unit-cell parameters a=55.37Å, b=55.37Å, c=338.0Å, α=β=90°, and γ=120°.