Dioxomolybdenum(VI) Complexes with Ene-1,2-dithiolate Ligands: Synthesis, Spectroscopy, and Oxygen Atom Transfer Reactivity

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• 作者：Hideki Sugimoto ; Susumu Tatemoto ; Koichiro Suyama ; Hiroyuki Miyake ; Shinobu Itoh ; Chao Dong ; Jing Yang ; Martin L. Kirk
• 刊名：Inorganic Chemistry
• 出版年：2009
• 出版时间：November 16, 2009
• 年：2009
• 卷：48
• 期：22
• 页码：10581-10590
• 全文大小：1001K
• 年卷期：v.48,no.22(November 16, 2009)
• ISSN：1520-510X

文摘

New dioxomolybdenum(VI) complexes, (Et₄N)(Ph₄P)[Mo^VIO₂(S₂C₂(CO₂Me)₂)(bdt)] (2) and (Et₄N)(Ph₄P)[Mo^VIO₂(S₂C₂(CO₂Me)₂)(bdtCl₂)](4)(S₂C₂(CO₂Me)₂ = 1,2-dicarbomethoxyethylene-1,2-ditholate, bdt = 1,2−benzenedithiolate, bdtCl₂ = 3,6-dichloro-1,2-benzenedithiolate), that possess at least one ene-1,2-dithiolate ligand were synthesized by the reaction of their mono-oxo-molybdenum(IV) derivatives, (Et₄N)₂[Mo^IVO(S₂C₂(CO₂Me)₂)(bdt)] (1) and (Et₄N)₂[Mo^IVO(S₂C₂(CO₂Me)₂)(bdtCl₂)] (3), with Me₃NO. Additionally, the bis(ene-1,2-dithiolate)Mo^VIO₂ complex, (Et₄N)(Ph₄P)[Mo^VIO₂(S₂C₂(CO₂Me)₂)₂] (6), was isolated. Complexes 2, 4, and 6 were characterized by elemental analysis, negative-ion ESI mass spectrometry, and IR spectroscopy. X-ray analysis of 4 and 6 revealed a Mo^VI center that adopts a distorted octahedral geometry. Variable-temperature ¹H NMR spectra of (CD₃)₂CO solutions of the Mo^VIO₂ complexes indicated that the Mo centers isomerize between Δ and Λ forms. The electronic structures of 2, 4, and 6 have been investigated by electronic absorption and resonance Raman spectroscopy and bonding calculations. The results indicate very similar electronic structures for the complexes and considerable π-delocalization between the Mo^VIO₂ and ene-1,2-dithiolate units. The similar oxygen atom transfer kinetics for the complexes results from their similar electronic structures.