The metal is the kinetic site of protonation of (diimine)Pt dimethyl complexes.
Protonolysis of (diimine)PtMe2 (1) complexes in CD2Cl2 containing CD3CN at -78 degrees C yields (diimine)PtMe2(H)(NCCD3)+ (4), (diimine)PtMe(NCCD3)+ (5), and methane. The relative yields of 5 and methane decrease with increasing concentrations of CD3CN. This is consistent with protonation of 1 occurring directly at the metal, rather than at a methyl group. The principle of microscopic reversibility then implies that the deprotonation in "Shilov-type C-H activation" occurs from a Pt(IV) hydridomethyl intermediate, rather than from a Pt sigma-methane complex.
Wik
Bror Johan
BJ
Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, N-0315 Oslo, Norway.
Lersch
Martin
M
Tilset
Mats
M