Transition metal thiocarbonyl complex

A transition metal thiocarbonyl complex is a coordination compound containing the ligand CS. Whereas metal carbonyl complexes are very common, even industrially important, only a few dozen thiocarbonyl complexes are known.[2]

Preparation

The main challenge for the preparation of thiocarbonyl complexes arises from the non-availability of carbon monosulfide. Thus, the CS ligand is often extruded from thiocarbonyl-containing precursors. One example involves thiophosgene, which reacts with disodium tetracarbonylferrate:

Na2Fe(CO)4 + CSCl2 → Fe(CO)4CS + 2 NaCl

Instead of thiophosgene, chlorothioformates (ClC(S)OAr) have also been used as a source of CS ligand. The thiocarbonyl analogue of Vaska's complex is prepared in this way.[4]

Carbon disulfide is another source of thiocarbonyl ligands, although CS2 is less electrophilic than thiophosgene and its alkoxy derivative. Carbon disulfide forms η2-CS2 complexes, which are susceptible to desulfurization. This pattern is illustrated by the reaction of Wilkinson's catalyst (RhCl(PPh3)3):[5]

RhCl(PPh3)3 + CS2 → RhCl(CS2)(PPh3)3
RhCl(CS2)(PPh3)3 → RhCl(CS)(PPh3)2 + SPPh3

The reaction of (C5H5)2Ni2(CO)2 with carbon disulfide gives ca 30% yield of (C5H5)3Ni3(CS)2, a trimetallic cluster with a triply bridging thiocarbonyl ligands. Many other thiocarbonyl complexes arise from similarly complicated reactions in modest yield.[2]

A variety of other routes have been developed, including addition of sulfur reagents to metal carbyne complexes.[2]

Structure and bonding

According to the Covalent bond classification method, terminal CS is classified as an L ligand, i.e., a charge-neutral Lewis base. With respect to HSAB theory, it is classified as soft. According to spectroscopic measurements, CS is a superior pi-acceptor relative to CO, as indicated by the shortness of M-CS vs M-CO bonds.[2]

Selenocarbonyl and tellurocarbonyl complexes

Several complexes of CSe and CTe have been characterized.[6] The first examples were prepared from the osmium dichlorocarbene complex.[7]

OsCl2(CCl2)(PPh3)2(CO) + 2 EH− → OsCl2(CE)(PPh3)2(CO) + 2 Cl− + H2E (E = Se, Te; Ph = C6H5)

References

  1. ^ Huang, Yining; Uhm, Haewon L.; Gilson, Denis F. R.; Butler, Ian S. (1997). "Phosphorus-31 Chemical Shift Anisotropies in Solid, Octahedral Chromium(0) Triphenylphosphine Derivatives". Inorganic Chemistry. 36 (3): 435–438. doi:10.1021/ic960816u.
  2. ^ a b c d Petz, W. (2008). "40 Years of Transition-Metal Thiocarbonyl Chemistry and the Related CSe and CTe Compounds". Coordination Chemistry Reviews. 252 (15–17): 1689–1733. doi:10.1016/j.ccr.2007.12.011.
  3. ^ Werner, H.; Kolb, O.; Schubert, U.; Ackermann, K. (1982). "Komplexe mit Kohlenstoffsulfiden und -seleniden als Liganden". Journal of Organometallic Chemistry. 240 (4): 421–428. doi:10.1016/S0022-328X(00)85144-X.
  4. ^ Hill, A. F.; Wilton-Ely, J. D. E. T. (2002). "Chlorothiocarbonyl bis(triphenylphosphine)iridium(I) [IrCl(CS)(PPh3)2]". Inorganic Syntheses. 33: 244–245. doi:10.1002/0471224502.ch4.
  5. ^ Baird, M. C.; Wilkinson, G. (1966). "Thiocarbonyl Complexes of Transition Metals". Chemical Communications (9): 267. doi:10.1039/C19660000267.
  6. ^ Frogley, Benjamin J.; Hill, Anthony F.; Watson, Lachlan J. (2020). "Advances in Transition Metal Seleno- and Tellurocarbonyl Chemistry". Chemistry – A European Journal. 26 (56): 12706–12716. Bibcode:2020ChEuJ..2612706F. doi:10.1002/chem.202001588. PMID 32356334.
  7. ^ Clark, George R.; Marsden, Karen; Roper, Warren R.; Wright, L. James (1980). "Carbonyl, Thiocarbonyl, Selenocarbonyl, and Tellurocarbonyl Complexes Derived from a Dichlorocarbene Complex of Osmium". Journal of the American Chemical Society. 102 (3): 1206–1207. Bibcode:1980JAChS.102.1206C. doi:10.1021/ja00523a070.
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