Activation of a C−H Bond in Indene by [(COD)Rh(μ<sub>2</sub>-OH)]<sub>2</sub><sup>†</sup>
作者:John E. Bercaw、Nilay Hazari、Jay A. Labinger
DOI:10.1021/om9004498
日期:2009.9.28
The air- and water-tolerant hydroxy-bridged rhodium dimer (COD)Rh(mu(2)-OH)](2) cleanly activates the aliphatic C-H bond in indene to generate [(COD)Rh(eta(3)-indenyl)]. The mechanism involves direct coordination of indene to the dimer followed by rate-determining C-H bond cleavage, in contrast to the previously reported analogous reactions of [(diimine)M(mu(2)-OH](2)(2+) (M = Pd, Pt), for which the dimer must be cleaved before rate-determining displacement of solvent by indene. Another difference is observed in the reactions with indene in the presence of acid: the Rh system generates a stable eta(6)-indene 18-electron cation, [(COD)Rh(eta(6)-indene)](+), that is not available for Pd and Pt, which instead form the eta(3)-indenyl C-H activation products. The crystal structure of [(COD)Rh (eta(6)-indene)] is reported.