Ultrafast UV pump/IR probe studies of C-H activation in linear, cyclic, and aryl hydrocarbons.
The photochemical C-H activation reactions of eta(3)-TpRh(CO)(2) (Tp = HB-Pz(3), Pz = 3,5-dimethylpyrazolyl) and CpRh(CO)(2) (Cp = C(5)H(5)) have been studied in a series of linear, cyclic, and aromatic hydrocarbon solvents on a femtosecond to microsecond time scale. These results have revealed that the structure of the hydrocarbon substrate affects the final C-H bond activation step, which is in accordance with the known preference of bond activation toward primary C-H sites. In the case of aromatic C-H activation, the reaction is divided into parallel channels involving sigma- and pi-solvated intermediates. Results for the analogous CpRh(CO)(2) molecule have shown that the coordination of the cyclopentadienyl ligand does not play a direct role in the dynamics of the reaction, in contrast to the C-H activation mechanism observed in eta(3)-TpRh(CO)(2) studies.
Asplund
Matthew C
MC
Department of Chemistry, University of California, Berkeley, California 94720, USA.
Snee
Preston T
PT
Yeston
Jake S
JS
Wilkens
Matthew J
MJ
Payne
Christine K
CK
Yang
Haw
H
Kotz
Kenneth T
KT
Frei
Heinz
H
Bergman
Robert G
RG
Harris
Charles B
CB