Synthesis, Structure, and Reactivity of Tungsten Acetylide鈥揋ermylene Complexes

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• 作者：Hiroyuki Sakaba ; Yasuhiro Arai ; Kensei Suganuma ; Eunsang Kwon
• 刊名：Organometallics
• 出版年：2013
• 出版时间：September 23, 2013
• 年：2013
• 卷：32
• 期：18
• 页码：5038-5046
• 全文大小：515K
• 年卷期：v.32,no.18(September 23, 2013)
• ISSN：1520-6041

文摘

The novel acetylide鈥揼ermylene complexes Cp*(CO)₂W(GePh₂)(CCR) (7a, R = SiMe₃; 7b, R = CMe₃) were synthesized by the reactions of Cp*(CO)₂W(NCMe)Me with Ph₂HGeC鈮R (R = SiMe₃, CMe₃). X-ray crystal analysis of 7a revealed significantly increased germylene鈥搕ungsten and decreased germylene鈥揳cetylide interactions in comparison to the corresponding interactions in the previously reported acetylide鈥搒ilylene complex Cp*(CO)₂W(SiPh₂)(CCSiMe₃) (1). Complexes 7a,b reacted with acetone to give the six-membered cyclic vinylidene complexes Cp*(CO)₂W鈺怌鈺怌(R)CMe₂OGePh₂ (8a, R = SiMe₃; 8b, R = CMe₃) by acetone insertion reaction, similar to the case of 1 affording Cp*(CO)₂W鈺怌鈺怌(SiMe₃)CMe₂OSiPh₂ (2). In the presence of 4-(dimethylamino)pyridine (DMAP), complexes 8a,b gave trans- and cis-DMAP-stabilized germylene acetylide complexes Cp*(CO)₂W(GePh₂路DMAP)(CCR) (trans- and cis-9a, R = SiMe₃; trans- and cis-9b, R = CMe₃) and acetone, showing a reactivity different from that of the silicon analogue 2. Complexes cis-9a,b were isolated as crystals from the reaction of 7a,b with DMAP and formed mixtures with trans-9a,b in solutions, respectively. A mixture of cis- and trans-9a reacted with acetone to form an equilibrium mixture with 8a and DMAP. The reactivity of 7a,b toward Me₃COH was also investigated to reveal the formation of the vinylidene complexes Cp*(CO)₂W{GePh₂(OCMe₃)}鈺怌鈺怌HR (10a, R = SiMe₃; 10b, R = CMe₃); 10a is equilibrated with 7a and Me₃COH, whereas 10b is further converted to the carbyne complex Cp*(CO)₂W鈮CH(CMe₃){GePh₂(OCMe₃)} (11).