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Dissertations / Theses on the topic 'OSMIUM COMPLEXES'

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Published: 4 June 2021
Last updated: 11 February 2022

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1

Rijt, Sabine H. van. "Osmium arene anticancer complexes." Thesis, University of Warwick, 2010. http://wrap.warwick.ac.uk/3213/.

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Drawbacks associated with anticancer chemotherapeutic cisplatin include tumour drug resistance, non-effectiveness against all tumours and lack of tumour-specificity resulting in severe side-effects (e.g. nausea, hair loss and kidney toxicity). The use of other metals such as transition metals rutheniumandosmium, may address the problems associated with platinum drugs and have received increased interest over the years. In this thesis the biological activity and aqueous solution chemistry of half-sandwichosmium (II) compounds of the type [(arene)OsII(X)(YZ)] n+ is explored. Chelating ligands containing nitrogen or nitrogen and oxygen donor atoms (N, NandN, O-chelatingligands) are investigated. It is shown that the chelating ligand has a large effect on the aqueous reactivity of the complexes. The introduction of functional groups on the chelate allowed for the ‘fine-tuning’ of the aqueous reactivity and nucleobase binding of the complexes. Also the nature of the coordinating arene was found to have an important effect on their biological activity. This could be rationalised by increased hydrophobicity with more extended arenes such as biphenylandtetrahydroanthracene, resulting in increased cellular uptake and increased cytotoxicity. Conjugating cell penetrating peptides to the complexes resulted in improved biological properties and opened a new way for functionalisation of the compounds. Several compounds reported in this thesis exhibit promising activity in the ovarian, colon and lung cancer cell lines and some could overcome cisplatin resistance in ovarian cisplatin resistant cell lines. Initial studies revealed cell death via apoptosis and the possible involvement of mitochondria in the apoptotic pathway. These results point to a novel pathway of activation for these complexes which is advantageous for addressing chemoresistance and effectiveness to oher types of cancers. This work shows that the biological properties of these compounds can be tuned by choice of ligands and also provides initial evidence for a novel pathway of activation.
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2

Fu, Ying. "Organometallic osmium arene anticancer complexes." Thesis, University of Warwick, 2011. http://wrap.warwick.ac.uk/52695/.

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The interest in the development of anticancer metal complexes for cancer therapy is growing spurred by the encouraging successful stories of platinum drugs. Osmium arene chlorido complexes had been found to show anticancer activity in vitro. In this thesis, the osmium arene iodido complexes were mainly explored and investigated. It is found that iodido OsII arene complexes with a general structure: [Os(η6- arene)(XY)I]PF6 (XY = p-hydroxy or p-dimethylamino phenylazopyridine, arene = p-cymene or biphenyl) are potently cytotoxic at nanomolar concentrations toward a panel of human cancer cell lines. In contrast to the chlorido osmium arene anticancer complexes, the iodido complexes are stable and inert toward aquation. More than thirty half sandwich azopyridine OsII arene complexes [Os(η6- arene)(azopyridine)X]+ (where X is chloride or iodide, the arene is p-cymene or biphenyl and the pyridine ring of azopyridine ligand bearing a variety of substituents) were synthesized and characterized. A preliminary structure activity relationships (SARs) were built up based on the anticancer activity towards A2780 human ovarian cancer cell line. In general, the introduction of an electronwithdrawing group (e.g. F, Cl, Br or I) at specific positions on the pyridine ring significantly increases cytotoxic activity and aqueous solubility. Changing the arene from p-cymene to biphenyl or the monodentate ligand (X) from chloride to iodide resulted in a significant increase in the anticancer activity. Studies in A2780 human ovarian cancer cells suggested that cellular uptake and targeting to cellular organelles play important roles in determining the anticancer activity. According to the 60 cancer cell lines screening results from National Cancer Institute (NCI), the anticancer activity achieved by the most potent OsII arene azopyridine complex is 100 times more than cisplatin; 1000 times activity was found in some cell lines. The mechanism of action may involve the inhibition of tubulin polymerization. One iodido osmium complex was selected for anticancer efficiency evaluation in vivo: [Os(η6-p-cym)(Azpy-NMe2)I]PF6 (FY026). This complex delayed the growth of HCT116 human colon cancer xenografts in mice, with negligible toxicity. It is the first example of in vivo antitumour activity for an organometallic osmium arene complex. Its activity appears to involve redox mechanisms. Its potency towards A2780 ovarian and A549 lung cancer cells is increased significantly when used in combination with L-buthionine-sulfoximine (L-BSO) indicating that L-BSO can be a good candidate for combination therapy treatment with iodido osmium complexes. Further study on the bioisosteres of FY026 was carried out by changing the azo bond (N=N) to imine bond (CH=N). Sixteen osmium arene iminopyridine complexes were synthesized, well characterized and showed good anticancer activity. Different structure-activity relationships comparing iminopyridine complexes with azopyridine complexes were identified which suggested a different anticancer mechanism. In contrast to FY026, [Os(η6-p-cym)(Impy- NMe2)I]PF6 (6) and [Os(η6-p-cym)(Impy-NMe2)Cl]PF6 (14) were found to undergo hydrolysis and the binding was observed between their hydrolyzed product (14A) and 9-ethylguanine. Moreover, a hydride transfer from NADH to form an osmium hydride intermediate which is involved in a catalytic process resulting in the formation of NAD+ was discovered. This process might be involved in the anticancer mechanism of action. A dual mechanism of action was proposed based in the interaction of these compounds with DNA nucleobase and catalytic oxidation of NADH.
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3

Birri, Anthony. "Thiopene complexes of ruthenium and osmium." Thesis, University College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394242.

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4

Peacock, Anna F. A. "Design of osmium arene anticancer complexes." Thesis, University of Edinburgh, 2006. http://hdl.handle.net/1842/15612.

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In this thesis the biological activity and aqueous solution chemistry of half-sandwich Os11 arene complexes of the type [(η6-arene)Os(XY)C1] is explored, and it is demonstrated that these properties can be tuned by careful choice of XY chelating ligand (N,N-, O,O- and N,O-chelates) to achieve cancer cytotoxicity comparable to carboplatin. The osmium complexes containing N,N-chelates hydrolyse more slowly than their ruthenium analogues and the pKa of the resulting water is more acidic. Efforts to increase the rates of hydrolysis and the resulting pKa led to replacement of the neutral N,N-chelating ligand by an anionic O,O-chelate. This was successful in that hydrolysis is more rapid and the pKa of the coordinated water has increased by ca 0.8 units. However, these complexes are deactivated by formation of the inert and thermodynamically stable hydroxo-bridged dimers. Attempts to tune the stability of complexes containing XY = O,O-chelate, by replacing the 6-membered O,O-chelate with 5-membered analogues, was partially successful for the development of active complexes, but was unsuccessful in preventing hydroxo-bridged dimer formation. Within the class of N,N- and N,O-chelated complexes the choice of donor group is important. Replacing amine N-donor groups with the Π-acceptor pyridine, reduced both the rate of hydrolysis and pKa or coordinated water, and increased the overall stability of the complex. This was especially the case for complexes containing N,O-chelates, which displayed aqueous chemistry in between that of the parent compounds containing neutral N,N-or anionic O,O-chelates. Within this group of osmium arene complexes, [(η6-arene)Os(N,O)C1], active cytotoxic complexes were obtained, and the first X-ray crystal structures of osmium bound to either G or A nucleobases is reported. This work shows that a wide range of reactivity can be obtained for complexes of the form [(η6-arene)Os(XY)C1]n+ by careful choice of the XY chelating ligand, and this knowledge has allowed complexes with cancer cell cytotoxicity to be designed.
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5

Luther, Thomas Alan. "Dicationic dihydrogen complexes of osmium and ruthenium /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/11540.

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6

McQueen, A. Ewan D. "1,1-dithiolate complexes of ruthenium and osmium." Thesis, University of Edinburgh, 1988. http://hdl.handle.net/1842/28608.

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7

Lam, Hon-wah. "Synthesis, reactivities and photochemistry of osmium-nitrido complexes /." [Hong Kong : University of Hong Kong], 1990. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12922444.

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8

Alyoubi, A. R. O. "Nuclear magnetic resonance studies of some osmium complexes." Thesis, University of Essex, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373208.

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9

Osman, Robert. "Photochemistry of polyphosphine complexes of Ruthenium and Osmium." Thesis, University of York, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358621.

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10

Needham, Russell James. "Organo-osmium anticancer complexes with novel azo-ligands." Thesis, University of Warwick, 2016. http://wrap.warwick.ac.uk/88273/.

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Piano-stool iodido Os(II) arene complexes containing AZPY (phenylazopyridine) π-acceptor bidentate ligands have been previously shown to exhibit potent anticancer activity and mechanisms of action that involve ROS generation, and differ greatly from early Os(II) arene complexes baring σ-donor bidentate ligands. The aim of this thesis was to explore Os(II) complexes containing other types of azo-ligands as well as continue our studies into AZPY complexes. Develop methods for improving the solubility of complexes, explore their intracellular activation, and further understand the mechanisms in which ROS levels are elevated inside cells. Firstly I explored Os(II) arene complexes with AZBTZ (phenylazobenzothiazole) bidentate liagnds. It was found that AZBTZ ligands can undergo unaided cyclometallation with Os(II) to form N,C-coordinated osmacycles as well as N,N-coordination. The amount of cyclo-metallation taking place seemed to be dependent on steric factors and occurred more for iodido complexes than chlorido and bromido analogues. The osmacycles were more stable than N,N-coordinated species and exhibited unique properties such as regio-specific deuteration of the aniline ring, but were too hydrophobic for biological evaluation. A total of 31 new Os(II) arene AZPY complexes were synthesised using the previously determined structure-activity relationships as a basis. The majority contained alkoxy and glycolic side chain substituents on the AZPY ligand, which was achieved via a novel synthesis protocol. Their trends in anti-cancer activity, solubility, lipophilicity and cell uptake were explored. It was found that varying the anion was the best method for improving aqueous solubility without affecting activity, lipophilicity or uptake. Key complexes were found to be very active against OE19 oesophageal cancer cells, were capable of inducing apoptosis and elevating ROS levels in A2780 cells, as well as causing cell cycle arrest in different phases of the cell cycle. Complexes [Os(ɳ6-p-cym)(5-EtO-AZPY)I]+ and [Os(ɳ6-p-cym)(AZPY-NMe2)I]+ were labelled with radioisotope 131I (β-/γ emitter, t½ 8.02 d) in Kings College London. They were relatively stable in human blood serum and cell culture medium over 24 h. However, in the presence of MCF-7 cells, rapid dissociation of the iodide monodentate ligand was observed in the supernatants. Cell uptake studies revealed a spike in 131I uptake after 5-10 min, which proceeds to steadily decline. The complexes seemed to undergo intracellular activation involving dissociation of the iodide ligand, and uptake of the complex is in competition with a rapid rate of iodide efflux, probably involving chloride transport channels. The aqua species, [Os(ɳ6-p-cym)(5-EtO-AZPY)H2O]2+, was synthesised and its pKa was determined as 4.55, meaning it exists predominantly as a +1 charged hydroxido species under physiological conditions. Using UV-Vis spectroscopy and EPR (DEPMPO spin trap), [Os(ɳ6-p-cym)(5-EtO-AZPY)OH]+, and its chlorido and iodido analogues were found to catabolise H2O2, generating HO· radicals in the process that were capable of cleaving lysozyme protein with effectiveness in the order OH > Cl > I. Interestingly it was discovered that iodide complexes are activated by iodide ligand dissociation in the presence of low concentrations of GSH (75 μM) to form the more active hydroxido species. However, in higher concentrations (7.5 mM), they formed Os-SG and Os-SOG adducts. Likewise, [Os(ɳ6-p-cym)(5-EtO-AZPY)OH]+ and its iodido analogue were both capable of oxidising NADH to NAD+ with effectiveness in the order OH > I. NADH was also capable of activating iodido species in a similar manner and generating the hydroxido species was required for NADH oxidation to proceed.
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11

Morewood, Catherine Alexandra. "π-complexes of osmium and ruthenium organometallic clusters." Thesis, University of Cambridge, 1995. https://www.repository.cam.ac.uk/handle/1810/272792.

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12

Bryce, Garry Thomas. "Palladium acylation catalysts and osmium cluster arene complexes." Thesis, University of Edinburgh, 1998. http://hdl.handle.net/1842/15491.

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The acyl palladium complex (bpy)Pd(COMe)(I) (bpy = 2,2'-bipyridyl) was synthesised, and reacted with a variety of different alkenes, cyclic alkenes and dienes, and arenes in an attempt to yield the inserted acyl complexes {(bpy)Pd(CxRYCOMe)}. The inserted complexes were the first stage in setting up a catalytic reaction with the Palladium complex acting as a catalyst in the synthesis of an acylated arene. The osmium cluster Os3(CO)10(NCMe)2, was reacted with a series of functionalised arenes of the type C6H4R1R2 (where R1 = H, R2 = F, Cl, Br, CHCH3, C(CH3)CH2 and Me; R1 = R2 = Me, R1 = R2 = C(CH3)CH2) yielding clusters of the type Os3(CO)9H2(C6H2R1R2). The crystallographic and spectroscopic data provides evidence of the different geometric forms that the complexes demonstrate with the different types of ligands. The osmium arene complexes were reacted further using a Friedel-Crafts acylation reaction to acylate the arene ring when it is attached to the cluster. The resultant complexes show a shifting of the IR bands in the IR to higher wavenumbers. The compound Os3(CO)9H2(C2H3F) reacted with 2-butyne yielding the complexes Os3(CO)8(H)(CH2CHCHCH3)(C6H3F) and Os3(CO)8H2(η2-2-butyne)(C6H3F) which were identified crystallographically and spectroscopically. These two complexes show two different bonding modes of the butyne ligand to metal centre.
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13

鍾偉祥 and Wai-cheung Chung. "Syntheses, characterization and reactivities of some high-valent osmium porphyrin complexes." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1987. http://hub.hku.hk/bib/B31230817.

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14

LaPointe, Anne Marie. "Alkyl, alkylidene, and alkylidyne complexes of rhenium and osmium." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11762.

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15

Gray, Jennifer C. "Ruthenium and osmium bis-arene complexes with biologically-active ligands." Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/2758.

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The inclusion of biologically-active ligands into organometallic complexes offers much scope for the design of novel drugs with enhanced, targeted activity. Studies on such complexes indicate that new mechanisms of action are possible when combining the bioactivity of the ligand with the properties inherent to the metal, leading to the possibility of overcoming current drug resistance pathways. This thesis is concerned with the synthesis and characterisation of ruthenium(II) and osmium(II) bis-arene complexes containing biologically-active ligands and their potential application as anticancer agents. Four groups of ligands are investigated: indole derivatives, aspartame, tamoxifen and flavonoids. Both indole derivatives studied resulted in the formation of complexes which were unstable, due to either polymerisation of the ligand or decomposition of the complex as a result of loss of the bound ligand with time. X-ray structural data obtained for [(eta6-p-cymene)Ru(eta6-1-methylindole-3-acetic acid)](PF6)2 revealed that the latter may be a result of partial loss of eta6-coordination due to tilting of the indole ring away from the metal. Much more stable complexes were generated with aspartame, however the effect of the metal on the structure, electronics, acidity and decomposition of the ligand all resulted in the complexes being incapable of binding to and activating the human sweet taste receptor. Antiproliferative studies found that ruthenium and osmium complexes of tamoxifen were not active against hormone-dependent mcf-7 breast cancer cells although they were able to mimic the isolated ligand under certain conditions. Here, the inactivity is most likely a result of the organometallic fragment being too bulky to fit into the receptor active site. Although no cytotoxic activity was observed, evidence of intercalation of the complexes into DNA was obtained. Dual anticancer activity was discovered for two ruthenium complexes of flavonoids: [(eta6-p-cymene)Ru(eta6-flavanone)](PF6)2 and [(eta6-biphenyl)Ru(eta6-flavanone)](PF6)2. Although the complexes are very similar in structure, the first displayed moderate cytotoxic activity against both A2780 and A549 cancer cells (IC50 30 – 40 microns), which may be a result of an observed DNA interaction, while the second was selectively highly cytotoxic towards A549 cancer cells (IC50 ~ 6 microns) and showed no evidence of targeting DNA. Moreover, antioxidant properties inherent to the ligands were found to be enhanced on metal binding, giving the complexes additional potential in applications for the prevention of cancer. Significantly, this work has identified the first anticancer active metal bis-arene complexes of biologically-active ligands, therefore demonstrating the validity of such an approach to the design of novel drugs.
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16

Barthram, Anita Marie. "Metal-metal interactions in polynuclear complexes of ruthenium and osmium." Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326683.

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17

Mockus, Nicholas V. "Investigating Linkage Isomerization in Sulfoxide Complexes of Ruthenium and Osmium." Ohio University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1194396549.

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18

Christie, Robert M. "Synthetic, spectroscopic and electrochemical studies of ruthenium and osmium complexes." Thesis, University of Edinburgh, 1989. http://hdl.handle.net/1842/13390.

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19

Taylor, Kenneth John. "Electrochemical and spectroelectrochemical studies on mixed halo/pyridine osmium complexes." Thesis, University of Edinburgh, 1990. http://hdl.handle.net/1842/13079.

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The complexes [OsCl6-nPYn](n-y)+ , where n = 0, 1, 2(trans), 2(cis), 3(mer), 4(trans), 5 and 6, and y varies between 2 and 4, have been synthesised via redox induced substitution reactions of [OsCl6]2-. The series has been fully characterised using electrochemical and spectroelectrochemical techniques. Several key members namely trans-[TPA] [OsCl4py2], cis-[OsCl4py2], trans-[OsCl2py4] and [Ospy6]9BF4]2, have also been examined by X-ray crystallography. Voltammetric data derived from these complexes has been compared to PROB*LEM/2 values predicted by two recent models. PROB*LEM/2 values for the series [OsCl6-nPYn](n-y), where y = 3 and 2, are dependent on n but independent of the isomeric form adopted. However, we propose that PROB*LEM/2 values for the series [OsCl6-nPYn](n-4)+ are dependent not only on n and the isomeric form, but also on the precise coordination mode of the pyridine ligands. As a comparison some members of the series [OsBr6-npyn](n-y)+ and [OsI6-npyn](n-y)+ , and complexes [TBA][OsCl5L], where L = PhCn, 2, 3 and 4-cyanopyridine and 3,4-dicyanopyridine, have also been synthesised and characterised using the methods described above. Kinetic studies on the reduction of [OsCl6]2- in the presence of pyridine, dmf and CO suggest Cl- loss is the rate determining step for this process.
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20

Payne, Nicholas N. "Electrochemical studies of mixed halo-phosphine/arsine osmium (III) complexes." Thesis, University of Edinburgh, 1997. http://hdl.handle.net/1842/15608.

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A series of complexes of general formula [OsX3L3] and [OsCl3L2L'] where X is a chloride or bromide and L and L' are different tertiary phosphines or arsines have been synthesised. The X-ray diffraction crystal structures of the complexes, mer-[OsCl3(PMe2Ph)3], mer-[OsCl3(PEt2Ph)3], mer-[OsBr3(PPrn3)3], mer-[OsCl3(AsME2Ph)3], mer-[OsCl3(PPrn2)2(AsPrn3)], mer-[OsCl3(PPrn2)2(PEtPh2)] and mer-[OsCl3(P(OMe)2Ph)2(AsPrn3)] show them to have slightly distorted octahedral metal environments with the trans influence of the Group 15 ligands evident. The mer complexes have been studied electrochemically and all show two one-electron processes; an oxidation and a reduction process. Both couples involve the osmium metal centre. The one electron reduction step is rapidly followed by a chemical reaction resulting in the formation of an electroactive daughter product of general formula [OsCl2L3Y] where Y is a neutral coordinating ligand. The chemical reaction has been studied by kinetic and spectrochemical methods. The redox potentials of the mer species gives a good linear correlation with Tolmans electronic parameter for the tertiary phosphine. The electronic spectra of the compounds have been recorded and the peaks assigned to specific electronic transitions via the use of Extended Huckel Molecular Orbital Calculations. Electrochemical elucidation of these systems has shown that the redox potentials of the complexes are predominantly dependent on one ligand, namely the phosphine/arsine trans to the halide. The fac isomers also show two metal based one-electron couples at very different potentials from the analogous mer isomers. The reduction also produces an electroactive daughter product. The oxidation results in the isomerisation of the fac isomer to that of the mer isomer. The kinetic parameters of the reaction have been measured, and a mechanism is proposed for the isomerisation.
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21

Ellul, Charles. "Trimetallic N-heterocyclic carbene complexes." Thesis, University of Bath, 2011. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.538279.

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22

鄭永堅 and Wing-kin Cheng. "Synthesis, reactivities, and electrochemistry of osmium complexes withmacrocyclic tertiary amine and multianionic amide and schiff-baseligands." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1989. http://hub.hku.hk/bib/B31231512.

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23

Cheng, Wing-kin. "Synthesis, reactivities, and electrochemistry of osmium complexes with macrocyclic tertiary amine and multianionic amide and schiff-base ligands /." [Hong Kong : University of Hong Kong], 1989. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12374118.

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24

Lam, Ngai Man. "Synthesis, crystal structures, and reactivity of ruthenium and osmium nitrido complexes /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?CHEM%202006%20LAMN.

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25

Salter, David Mark. "The synthesis and reactivity of new ruthenium and osmium silyl complexes." Thesis, University of Auckland, 1993. http://hdl.handle.net/2292/1965.

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The chemistry of transition metal silyl complexes still remains relatively undeveloped despite the recent advances that have been made in this area. This thesis describes the synthesis and reactivity of new ruthenium and osmium silyl complexes. A general survey on the bonding, preparation and reactivity of transition metal silyl complexes is given in chapter one as an introduction to the chemistry discussed in the following chapters. Several reviews relating to transition metal-silicon chemistry have been published, 1-5 and therefore only the major features and more recent developments are highlighted in this overview. Emphasis has been placed on those aspects not previously reviewed. Coordinatively unsaturated transition metal silyl complexes are uncommon and the chemistry of these complexes has been virtually unexplored. The synthesis of the novel coordinatively unsaturated ruthenium and osmium silyl complexes, M(SiR3)Cl(CO)(PPh3)2 (M=Ru, Os; R=Cl, alkyl group, alkoxy group), is described in chapter two. The reaction of M(Ph)Cl(CO)(PPh3)2 (M=Ru, Os) with a silane, in some instances, provided a facile, high yield route to complexes of the type M(SiR3)Cl(CO)(PPh3)2 (M=Ru; SiR3=SiMe3, SiEt3, SiCl3, SiMe2Cl; M=Os; SiR3=SiCl3, SiMe2Cl). The chlorosily1 complexes were also prepared by treatment of MHCl(CO)(PPh3)3 (M=Ru, Os) with HSiCl3 and HSiMe2Cl. X-ray crystal structures were obtained of Ru(SiEt3)Cl(CO)(PPh3)2 and Os(SiCl3)Cl(CO)(PPh3)2. Complexes containing chlorosily1 ligands proved synthetically useful, undergoing a variety of nucleophilic substitution reactions at silicon with retention of the transition metal-silicon bond. New complexes synthesized by this method included Ru[Si(OEt)3]Cl(CO)(PPh3)2 and Os(SiMe3)Cl(CO)(PPh3)2. X-ray crystal structures of these two compounds were also obtained. These exchange reactions illustrate a route to new transition metal silyl compounds that has rarely been utilised. Also described in chapter two is the unprecedented formation of the novel compound Os(SiMe2C6H4PPh2)(C6H4PPh2)(CO)(PPh3), resulting from phenylation at silicon. The structure of this complex was determined by X-ray crystallography. In chapter three, addition of the Lewis bases CO and CN(p-tolyl) to coordinatively unsaturated silyl complexes, M(SiR3)Cl(CO)(PPh3)2 (M=Ru, Os), is described. The coordinatively saturated osmium silyl complexes Os(SiR3)Cl(CO)L(PPh3)2 (SiR3=SiCl3, SiMe2Cl, SiMe2OEt, SiMe3; L=CO, CNR) were generated in this way. Similarly, addition of 4,4'-dimethyl-2,2'-bipyridine to Ru(SiEt3)Cl(CO)(PPh3)2 afforded Ru(siEt3)Cl(dimethylbipy)(CO)(PPh3). The six-coordinate complex Ru(SiEt3)(η2-S2CNMe2)(CO)(PPh3)2 was synthesized by displacement of the labile chloride ligand from Ru(SiEt3)Cl(CO)(PPh3)2 by the dimethyldithiocarbamate anion. Characterization of Ru(SiEt3)(η2-S2CNMe2)(CO)(PPh3)2 included an X-ray crystallographic analysis. The exchange of silyl groups at the metal was also observed in several reactions. For example, heating Ru(SiMe3)Cl(CO)(PPh3)2 in the presence of excess HSiEt3 yielded Ru(SiEt3)Cl(CO)(PPh3)2. These reactions illustrate aspects of the chemistry that can occur at the metal centre of coordinatively unsaturated transition metal silyl complexes. Another route to coordinatively saturated osmium silyl complexes was via oxidative addition of a silane to Os(CO)2(PPh3)3, which yielded Os(SiR3)H(CO)2(PPh3)2 (SiR3=SiMe3, SiEt3, SiPh3, SiPh2H). The synthesis of these complexes is also discussed in chapter three. An X-ray crystal structure determination of Os(SiEt3)H(CO)2(PPh3)2 confirmed the presence of mutually trans carbonyl ligands. The first thiocarbonyl-containing transition metal silyl complexes, M(SiMe2Cl)Cl(CS)(PPh3)2 (M=Ru, Os), were prepared by treating M(Ph)Cl(CS)(PPh3)2 or MHCl(CS)(PPh3)3 with HSiMe2Cl. The Si-Cl bond in these compounds reacted readily with nucleophiles, yielding M(SiMe2OR)Cl(CS)(PPh3)2 (OR=OEt, OMe, OH). In contrast to the addition of CO to Os(SiR3)Cl(CO)(PPh3)2, addition of CO to Ru(SiMe2R)Cl(CS)(PPh3)2 (R=Cl, OEt, OMe, OH) and to Os(SiMe2OEt)Cl(CS)(PPh3)2 afforded dihapto-thioacyl complexes, M[η2-C(S)SiMe2R]Cl(CO)(PPh3)2, via a migratory insertion reaction involving the silyl group and the thiocarbonyl ligand. This reaction represents the first formal insertion of CS into a transition metal-silicon bond. The structure of Ru[η2-C(S)SiMe2OEt]Cl(CO)(PPh3)2 was obtained by X-ray crystallography and confirmed that bonding of the thioacyl ligand occurred in a dihapto fashion. These reactions are described in chapter four. When Os(Ph)Cl(CO)(PPh3)2 was reacted with HSiMe3, the formally osmium(IV) silyl complex Os(SiMe3)H3(CO)(PPh3)2 was produced. Few compounds of this type are known. The synthesis, characterization and reactivity of Os(SiMe3)H3(CO)(PPh3)2 are discussed in chapter five. The crystal structure of Os(SiMe3)H3(CO)(PPh3)2 is also depicted. In solution, Os(SiMe3)H3(CO)(PPh3)2 appeared to be in equilibrium with the highly reactive, coordinatively unsaturated species OsH2(CO)(PPh3)2. The reaction of Os(SiMe3)H3(CO)(PPh3)2 with HSiR3 (R=Et, Ph), HSn(p-tolyl)3 and HC2Ph was carried out, using Os(SiMe3)H3(CO)(PPh3)2 as an in situ source of OsH2(CO)(PPh3)2. These reactions afforded Os(SiR3)H3(CO)(PPh3)2 (R=Et, Ph), Os[Sn(p-tolyl)3]2H2(CO)(PPh3)2 and OsH(C2Ph)(CO)(PPh3)3 respectively, most likely via a series of oxidative addition-reductive elimination reactions involving OsH2(CO)(PPh3)2. Transition metal hydroxysilyl complexes are extremely rare. Only three systems have been reported containing a hydroxysilyl group bonded to a transition metal. 6,7,8 Chapter six deals with the formation of compounds of this type. Hydroxysilyl-containing complexes of ruthenium and osmium were obtained via the hydrolysis of M(SiMe2Cl)Cl(CO)(PPh3)2 and M(SiCl3)Cl(CO)(PPh3)2. The complexes M[Si(OH)3]Cl(CO)(PPh3)2 are the first trihydroxysilyl-containing transition metal complexes and therefore represent a new class of transition metal silyl compounds. Characterization of Os[Si(OH)3]Cl(CO)(PPh3)2 included an X-ray crystal structure which showed that, remarkably, no inter- or intra-molecular hydrogen bonding of the type O(H)···O or O(H) ··Cl was associated with the Si(OH)3 group. In contrast, intermolecular hydrogen bonding was found by X-ray crystallography for the dicarbonyl derivative, Os[Si(OH)3]Cl(CO)2(PPh3)2. Subsequent reactions involving Os[Si(OH)3]Cl(CO)(PPh3)2 led to the synthesis of the diosmium tetrahydroxydisiloxane complex, [OsCl(CO)(PPh3)2Si(OH)2-]2O. For example, [OsCl(CO)(PPh3)2Si(OH)2-]2O was isolated after Os(SiCl3)Cl(CO)(PPh3)2 was added to a dichloromethane solution of Os[Si(OH)3]Cl(CO)(PPh3)2. Formation of this tetrahydroxydisiloxane compound is significant and models the first condensation reaction generating a Si-O-Si linkage in the hydrolysis of organochlorosilanes to polysiloxanes. The Si-O-Si linkage was clearly visible in the X-ray crystal structure of [OsCl(CO)(PPh3)2Si(OH)2-]2O. Chapter seven provides a short conclusion, highlighting the important features of the work discussed in this thesis and identifies areas for future investigation.
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26

Coombe, V. T. "Synthetic, spectroscopic, and electrochemical studies on complexes of ruthenium and osmium." Thesis, University of Edinburgh, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355956.

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梁嘉茵 and Ka-yan Sarana Leung. "Complexes of iminato, nitrido, imido, and hydrazido ruthenium of osmium porphyrins." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B31243307.

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Leung, Ka-yan Sarana. "Complexes of iminato, nitrido, imido, and hydrazido ruthenium of osmium porphyrins /." Hong Kong : University of Hong Kong, 2002. http://sunzi.lib.hku.hk/hkuto/record.jsp?B25212072.

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29

Wen, Ting Bin. "Alkyne activation and carbon-carbon bond formation mediated by osmium complexes /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?CHEM%202003%20WEN.

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30

Bungane, Ntombovuyo. "Ruthenium and osmium complexes as catalyst precursors for Fischer-Tropsch synthesis." Master's thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/6296.

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Includes bibliographical references (leaves 63-65).
Ruthenium complexes of several types have been synthesized, supported on silica and their activity in CO hydrogenation was investigated in order to determine the cluster size of surface Ru atoms required for the formation of hydrocarbons. Previous studies have shown that more than one metallic site is needed for the Fischer-Tropsch synthesis.
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31

McFadzean, Belinda Julie. "The kinetics and associated equilibria of high oxidation state osmium complexes." Thesis, Nelson Mandela Metropolitan University, 2007. http://hdl.handle.net/10948/732.

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The reduction of osmium tetroxide by a series of alcohols was studied spectrophotometrically. The reaction was observed to occur in two steps, unlike previously reported studies on this reaction. The identities of both reactants and products were established via a range of techniques. Equilibrium and kinetic data were gathered and reaction models were evaluated using equilibrium and kinetic modelling software. The following complexation reaction model emerged that simulates both the equilibrium and kinetic data. Os(VIII) + RCH2OHOs(VI) + RCHO2 Os(VIII) + Os(VI)k+2k1Complexk-2 Conditional rate constants and equilibrium constants were generated. Rate constants for the alcohol reactions were correlated with the Taft σ* constant. The ρ* value obtained (-1.4) is consistent with a hydride transfer mechanism coupled with synchronous removal of the hydroxyl proton. The identity of the osmium(VIII)-osmium(VI) complex has been suggested. Thermodynamic parameters were also reported. The rate constants for benzyl alcohol and 2-chloroethanol deviated from those predicted by the Taft plot. An explanation of enhanced resonance effects is offered for benzyl alcohol and an alternative reaction mechanism, involving proton abstraction, is offered for 2-chloroethanol. The reaction of the oxidation products of alcohols, namely ketones, with osmium tetroxide produced rate constants that were, perhaps surprisingly, far larger than those of the alcohols. A reaction mechanism for the oxidation of the ketones is suggested, which involves the enolate ion as the reactive starting reagent.
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32

Coleman, Karl Stuart. "Synthesis and reactions of low-valent osmium and ruthenium fluoride complexes." Thesis, University of Leicester, 1996. http://hdl.handle.net/2381/34057.

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A range of low-valent osmium and ruthenium fluoride complexes of the type [OC-6-13][MF2(CO)2(L)2], L = tertiary phosphine, arsine or nitrogen donor ligand, have been prepared and fully charcacterized by a combination of mass spectrometry, infrared spectroscopy, 19F, and 31P{1H} (where appropriate) NMR spectroscopies. The compounds [OC-6-13][RuF2(CO)2(PEtPh2)2], [OC-6-13][OsF2(CO)2(PPh3)2] and [OC-6-13][OsF2(CO)2(PCy3)2] have been further characterized by single crystal X-ray diffraction, the last two representing the first crystallographic analyses of osmium(II) fluoride complexes. The photolysis and thermolysis of [RuF2(CO)2(PMe3)2] have been shown to give several novel complexes including [RuF2(CO)(PMe3)3] which is a rare example of fluoride ligand trans to tertiary phosphine. Reactions of some of the prepared complexes with a variety of reagents have given rise to a number of low-valent cationic fluoride complexes as well as novel alkyl and carboxylato species. Fluorination of the ruthenium carbonyl [Ru3(CO)12] with elemental fluorine has given rise to a plethora of products which have been characterized by 19F NMR spectroscopy. Hydride complexes of the type [MH2(CO)2(PPh3)2] and [MH2(CO)(PPh3)3] have been allowed to react with anhydrous hydrofluoric acid and have been shown to give the complexes [MF2(CO)2(PPh3)2] and [M2(?-F)3(CO)2(PPh3)4]+ respectively, where M = osmium or ruthenium. X-ray crystal structure determinations for the complexes [OC-6- 75][Os(CH3)2(CO)2(PPh3)2], [OC-6-13][Os(CH3)2(CO)2(PCy3)2], [OC-6-13]-[Ru(OC(O)CF3)2(CO)2(PCy3)2] and [Ru(?2-CO3-OO)(CO)(PMe3)3] are described.
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33

Wätjen, Florian. "Rhenium and Osmium PNP Pincer Complexes for Nitrogen Fixation and Nitride Transfer." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2019. http://hdl.handle.net/21.11130/00-1735-0000-0005-12D8-3.

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34

Li, Yan, and 李艷. "Synthesis and reactivity of carbene complexes of iron, ruthenium and osmium porphyrins." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B31245730.

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35

林曉楓 and Hiu-fung Lam. "Photophysical and photochemical properties of oxo and nitrido complexes of osmium(VI)." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B42576490.

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36

Lam, Hiu-fung. "Photophysical and photochemical properties of oxo and nitrido complexes of osmium(VI)." Click to view the E-thesis via HKUTO, 2001. http://sunzi.lib.hku.hk/hkuto/record/B42576490.

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37

Jolliffe, Jennifer Mary. "New ruthenium and osmium oxo complexes and their use as organic oxidants." Thesis, Imperial College London, 1991. http://hdl.handle.net/10044/1/46845.

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38

Garg, Komal. "Synthesis and Spectroscopic Characterization of Photochromic Ruthenium and Osmium Chelating Sulfoxide Complexes." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1399471229.

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39

Horsburgh, Lockhart E. "Synthesis and characterisation of novel, redox-active complexes of ruthenium and osmium." Thesis, University of Edinburgh, 1994. http://hdl.handle.net/1842/14099.

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This thesis reports the synthesis and characterisation of a number of novel complexes of Ru and Os. The complexes studied all have more than one redox centre. A major objective of this research was investigation of the redox behaviour of the complexes formed, primarily by electrochemical and in situ spectroelectrochemical studies. In chapter 1 the electrochemical and in situ spectroelectrochemical techniques employed during this work are discussed. Chapters 2 and 3 report reactions of tetracyanoethylene (tcne) and tetracyanoquinodimethane (tcnq) with various complexes of Ru and Os. In the vast majority of cases tcnx (x = e or q) was found to coordinate to the metal centre via nitrogen. Electrochemical and spectroelectrochemical studies were employed to elucidate the nature of the frontier orbitals. In general the complexes exhibited facile ligand-based reductions while oxidative processes were metal-based. In chapter 2 reactions of tcnx with cis-Ru(bpy) 2C12 (bpy = 2,2'-bipyridyl), and electrochemically induced reactions of tcne with [OsC16]2-, [OsBr6]2- and [OsC15(py)]- (py = pyridine) are reported. Chapter 3 discusses reactions of tcnx with phosphine complexes of Ru and Os. Of particular interest was the formation of trans-[OsC12(PEt2Ph) 3{(NC)2C=C(OH) (CN)}, the first reported example of metal-bound tricyanovinyl alcohol. In addition to studies of the redox processes, the mechanism of formation of the above complex was investigated. Chapter 4 discusses trinuclear mixed valence complexes of general formula XL2Ru(μ-X) 3Ru(μ-X)3RuL2X, where X = C1 or Br and L is a tertiary phosphine or arsine. In particular the nature of the metal-metal interactions was investigated, primarily by single crystal X-ray diffraction, electrochemistry and spectroelectrochemistry. The results obtained are generally consistent with Ru-Ru bonding and extensive delocalisation of the metal-based valence electrons.
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40

Sorbie, Ruth J. "Electrochemical and spectroelectrochemical studies of some binuclear complexes of ruthenium and osmium." Thesis, University of Edinburgh, 1989. http://hdl.handle.net/1842/14452.

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41

Xie, Jin. "Synthesis, structures and spectroscopic properties of primary and secondary phosphine complexes of iron, ruthenium and osmium porphyrins." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/HKUTO/record/B39556876.

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42

錢國輝 and Kwok-fai Chin. "Syntheses, electrochemistry and photophysical and photochemical properties of some high-valent oxo, nitrido and amido complexes ofosmium." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1995. http://hub.hku.hk/bib/B31234756.

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Chin, Kwok-fai. "Syntheses, electrochemistry and photophysical and photochemical properties of some high-valent oxo, nitrido and amido complexes of osmium /." Hong Kong : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B17506128.

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44

Hung, Wai Yiu. "Syntheses and reactivities of osmium and ruthenium complexes with metal-carbon triple bonds /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?CHEM%202006%20HUNG.

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45

梁偉豪 and Wai-ho Wilkie Leung. "Synthesis, reactivities and electrochemistry of ruthenium and osmium oxo complexes with polypyridine ligands." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1989. http://hub.hku.hk/bib/B31231883.

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46

Leung, Wai-ho Wilkie. "Synthesis, reactivities and electrochemistry of ruthenium and osmium oxo complexes with polypyridine ligands /." [Hong Kong : University of Hong Kong], 1989. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12474332.

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47

張碧玉 and Pik-yuk Christine Cheung. "Crystal structure analysis of imido, nitrido and oxo complexes of rhenium (V), osmium (VI) and ruthenium (III) and some complexes oftrinuclear gold (I)." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1991. http://hub.hku.hk/bib/B31210211.

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48

Cheung, Pik-yuk Christine. "Crystal structure analysis of imido, nitrido and oxo complexes of rhenium (V), osmium (VI) and ruthenium (III) and some complexes of trinuclear gold (I) /." [Hong Kong : University of Hong Kong], 1991. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13138327.

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49

任詠華 and Wing-wah Vivian Yam. "High-valent ruthenium and osmium oxo complexes for homogeneous and photochemical oxidations of inorganic and organic substrates." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1988. http://hub.hku.hk/bib/B31231421.

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50

Yam, Wing-wah Vivian. "High-valent ruthenium and osmium oxo complexes for homogeneous and photochemical oxidations of inorganic and organic substrates /." [Hong Kong : University of Hong Kong], 1988. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12361434.

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