Investigation of Coordination Modes of Organosulfur Ligands to osmium and Rhodium Carbonyl Clusters- Possible Relevance to Hydrodesulfurization Reactions

Research output: ThesisDoctoral Thesis (compilation)

Abstract

The coordination and fundamental transformations of organosulfur compounds to polynuclear metal complexes has been studied as models for possible surface species in industrial HDS processes. Reactions between [Os3(CO)11(NCMe)] and various thiols have been studied by UV-Vis, IR and NMR spectroscopy and all experimental findings indicate that the reactions proceed via a two-step consecutive process involving the intermediate [Os3(CO)11(RSH)], which contains an agostic Os-H-S interaction, and which leads to the formation of the final product [Os3(CO)10(m-H)(m-SR)]. Reaction of [Rh4(CO)12] with para-thiocresol leads to a quantitative conversion to the dimeric complex [Rh2(CO)4(m-SC6H4-p-Me)]. The reaction involves evolution of H2 which was detected by GC-MS. Reaction of [Os3(CO)11(NCMe)] with thioethers results in the formation of [Os3(CO)11(L)] (L= thioether). The reaction of [Os3(CO)10(NCMe)2] with thioethers is less predictable and monosubstituted as well as disubstituted clusters are observed. Thioethers with aryl substituents undergo oxidative addition of a C-H bond of an aryl ring when reacted with [Os3(CO)10(NCMe)2]. Reaction of [Os3(m-H)2(CO)10] with thioethers does not lead to discernable products except when carried out in the presence of trimethylamine N-oxide, which leads to clusters of the general formula [Os3(m-H)2(CO)9(L)] (L= thioether). Thermal treatment of [Os3(CO)12] with Ph2P(C4H3S) and Ph2P(C8H5S) at 110 °C results in the formation of the simple substitution products [Os3(CO)12-n{Ph2PR}n] (n=1-3, R= -C4H3S, -C8H5S). At elevated temperatures C-H activation as well as sulfur coordination is observed for Ph2P(C8H5S). Treatment of Ph2P(C4H3S) and Ph2P(C8H5S) with [Os3(m-H)2(CO)10] at room temperature leads to the expected clusters [HOs3(m-H)(CO)10{Ph2PR}] (R= -C4H3S, -C8H5S), but at higher temperatures further metallation as well as sulfur coordination is observed. Several of the products of the reactions with diphenyl-2-thienylphosphine and diphenyl-benzothienylphosphine showed fluxional behavior and the dynamic behaviors have been studied by variable temperature 1H and 31P{1H} NMR spectroscopy.

Details

Authors
  • Nitsa Kiriakidou-Kazemifar
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Inorganic Chemistry

Keywords

  • thioethers, thiols, HDS processes, organosulfur compounds, polynuclear metal complexes, Metallorganisk kemi, Organometallic chemistry, thiophenes
Original languageEnglish
QualificationDoctor
Awarding Institution
Supervisors/Assistant supervisor
Award date2002 Dec 20
Publisher
  • Inorganic Chemistry, Chemical Center, Lund University
Print ISBNs91-628-5510-7
Publication statusPublished - 2002
Publication categoryResearch

Bibliographic note

Defence details Date: 2002-12-20 Time: 10:15 Place: Lecture Hall E, Chemical Center, Lunds University, External reviewer(s) Name: Deeming, Antony Title: [unknown] Affiliation: Department of Chemistry, University College London, 20 Gordon Street, GB-London WC1H OAJ, UK --- Article: This thesis consists of a summary of six papers, referred to by their roman numerals. Article: I. Detection of a novel intermediate in the addition of thiols to osmium carbonyl clusters.K. Kiriakidou, M.R. Plutino, F. Prestopino, M. Monari, M. Johansson,L. I. Elding, E. Valls, R. Gobetto, S. Aime and E. NordlanderChem. Commun., 1998, 2721. Article: II. Detection and characterization of a transient triosmium cluster containing an agostic Os-H-S interactionNitsa K. Kiriakidou-Kazemifar, Rosaria M. Plutino, Fabio Prestopino, Magda Monari, Lars Ivar Elding, Esteve Valls, Roberto Gobetto, Silvio Aime and Ebbe Nordlandermanuscript Article: III. Formation of rhodium carbonyl thiolate dimers via elimination of dihydrogen; crystal and molecular structure of [Rh2(CO)4(m-SC6H4CH3)2]Nitsa K. Kiriakidou-Kazemifar, Matti Haukka, Tapani Pakkanen, Sergey P. Tunik and Ebbe NordlanderJ. Organomet. Chem., 2001, 623, 65-73 Article: IV. Synthesis and characterization of new thioether derivatives of [Os3(CO)12] and [H2Os3(CO)10]; crystal and molecular structures of [Os3(CO)11(L)] [L= SEt2, SPr2, S(CH2)5] and [Os3(CO)9(m-H)(m-X){SMe(But)}] (X=H, OH).Nitsa K. Kiriakidou-Kazemifar, Eike Kretzschmar, Håkan Carlsson, Magda Monari, Simona Selva and Ebbe NordlanderJ. Organomet. Chem., 2001, 623, 191-201 Article: V. Syntheses and fluxional processes of diphenyl-2-thienylphosphine derivatives of triosmium clustersNitsa K. Kiriakidou Kazemifar, Marc J. Stchedroff, M. Abdul Mottalib, Simona Selva, Magda Monari, and Ebbe Nordlandermanuscript Article: VI. Reactions of diphenyl-2-benzothienylphosphine with trinuclear osmium clusters; coordination of the thienyl sulfur without ring openingNitsa K. Kiriakidou Kazemifar, Marc J. Stchedroff, M. Abdul Mottalib, Maria H. Johansson, Magda Monari, Simona Selva and Ebbe Nordlandermanuscript