d1 Oxosulfido-Mo(V) Compounds: First Isolation and Unambiguous Characterization of an Extended Series

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• 作者：Christian J. Doonan ; Craig Gourlay ; David J. Nielsen ; Victor W. L. Ng ; Paul D. Smith ; David J. Evans ; Graham N. George ; Jonathan M. White ; Charles G. Young
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：July 6, 2015
• 年：2015
• 卷：54
• 期：13
• 页码：6386-6396
• 全文大小：550K
• ISSN：1520-510X

文摘

Reaction of Tp^iPrMo^VIOS(OAr) with cobaltocene in toluene results in the precipitation of brown, microcrystalline oxosulfido-Mo(V) compounds, [CoCp₂][Tp^iPrMo^VOS(OAr)] (Cp^{鈥?/sup> = 畏5-C₅H₅鈥?/sup>, TpiPr鈥?/sup> = hydrotris(3-isopropylpyrazol-1-yl)borate, OAr鈥?/sup> = phenolate or 2-sBu, 2-tBu, 3-tBu, 4-sBu, 4-Ph, 3,5-sBu₂, 2-CO₂Me, 2-CO₂Et or 2-CO₂Ph derivative thereof). The compounds are air- and water-sensitive and display 谓(Mo鈺怬) and 谓(MoS) IR absorption bands at ca. 890 and 435 cm鈥?, respectively, 20鈥?0 cm鈥? lower in energy than the corresponding bands in TpiPrMoOS(OAr). They are electrochemically active and exhibit three reversible cyclovoltammetric waves (E(MoVI/MoV) = 鈭?.40 to 鈭?.66 V, E([CoCp₂]+/CoCp₂) = 鈭?.94 V and E(CoCp₂/[CoCp₂]鈭?/sup>) = 鈭?.88 V vs SCE). Structural characterization of [CoCp₂][TpiPrMoOS(OC₆H₄CO₂Et-2)]路2CH₂Cl₂ revealed a distorted octahedral Mo(V) anion with Mo鈺怬 and MoS distances of 1.761(5) and 2.215(2) 脜, respectively, longer than corresponding distances in related TpiPrMoOS(OAr) compounds. The observation of strong S(1s) 鈫?(S(3p) + Mo(4d)) S K-preedge transitions indicative of a d1 sulfido-Mo(V) moiety and the presence of short Mo鈺怬 (ca. 1.72 脜) and MoS (ca. 2.25 脜) backscattering contributions in the Mo K-edge EXAFS further support the oxosulfido-Mo(V) formulation. The compounds are EPR-active, exhibiting highly anisotropic (螖g 0.124鈥?.150), rhombic, frozen-glass spectra with g₁ close to the value observed for the free electron (g_e = 2.0023). Spectroscopic studies are consistent with the presence of a highly covalent MoS 蟺* singly occupied molecular orbital. The compounds are highly reactive, with reactions localized at the terminal sulfido ligand. For example, the compounds react with cyanide and PPh₃ to produce thiocyanate and SPPh₃, respectively, and various (depending on solvent) oxo-Mo(V) species. Reactions with copper reagents also generally lead to desulfurization and the formation of oxo-Mo(V) or -Mo(IV) complexes.}