Three-Coordinate Nickel Carbene Complexes and Their One-Electron Oxidation Products

详细信息    查看全文

• 作者：Vlad M. Iluc ; Gregory L. Hillhouse
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：April 30, 2014
• 年：2014
• 卷：136
• 期：17
• 页码：6479-6488
• 全文大小：530K
• 年卷期：v.136,no.17(April 30, 2014)
• ISSN：1520-5126

文摘

The synthesis and characterization of two new carbene complexes, (dtbpe)Ni鈺怌H(dmp) (1; dtbpe = 1,2-bis(di-tert-butylphosphino)ethane; dmp = 2,6-dimesitylphenyl) and (dippn)Ni鈺怌H(dmp) (2; dippn = 1,8-bis(di-iso-propylphosphino)naphthalene), are described. Complexes 1 and 2 were isolated by photolysis of the corresponding side-bound diazoalkane complexes, exemplified by (dtbpe)Ni{畏²-N₂CH(dmp)} (3). The carbene complexes feature Ni鈥揅 distances that are short and Ni鈥揅鈥揅 angles at the carbene carbon that are intermediate between 120掳 and 180掳 (155.7(3)掳 and 152.3(3)掳, respectively). The difference between the two carbenes became obvious when their reactivity toward 1-electron oxidizing agents was studied: the oxidation of 1 led to an internal rearrangement and the formation of a nickel(I) alkyl [{魏²-P,C-di-tert-butylphosphino-di-tert-butyl-PCH(dmp)ethane}Ni][BAr^F₄] (4), while the oxidation of 2 allowed the isolation of an unrearranged product, formulated as the cationic nickel(III) carbene complex[(dippn)Ni鈺怌H(dmp)][BAr^F₄] (6). Both oxidations are chemically reversible and the respective reductions lead to the neutral carbene complexes, 1 and 2.