88704-00-1Relevant articles and documents
Isotope Effects in Arene C-H Bond Activation by
Jones, William D.,Feher, Frank J.
, p. 4814 - 4819 (2007/10/02)
The isotope effects involved in the activation of arene C-H bonds by the intermediate have been investigated.The ratio kH/kD for coordination to a double bond in benzene (the rate-determining step of arene activation) is found to be 1.05(6), whereas kH/kD=1.4 for the second step in which the C-H bond of the coordinated arene undergoes oxidative addition.The isotope effect KH/D for the equilibrium between the more stable phenyl hydride complex (C5Me5)Rh(PMe3)(C6D5)H and the complex containing hydrogen in the ortho position of the phenyl ring (C5Me5)Rh(PMe3)(o-C6D4H)D shows a preference for hydrogen (vs. deuterium) on the metal of 2.7.The kinetic isotope effect for reductive elimination and dissociation of m-xylene from (C5Me5)Rh(PMe3)(3,5-C6H3Me2)H vs. (C5Me5)Rh(PMe3)(3,5-C6H3Me2)D is found to be inverse, with kH/kD=o.51.Analysis of the data for the deuterated benzene derivatives confirms that the kinetic isotope for the reductive elimination step is inverse.Attemps to prepare the complex (C5Me5)Rh(PMe3)(CH3)D by reduction of + with - resulted in the formation of both (C5Me5)Rh(PMe3)(CH3)D and (C5Me5)Rh(PMe3)(CH2D)H.
