DYNAMICS OF REACTIVE INTERMEDIATES AS PROBED BY FLASH-PHOTOLYSIS - THE RHODIUM(I) COMPLEXES RHCL(CO)PPH32, RHCL(CO)P(PARA-TOLYL) 32 OR RHCL(CO) PME32

Flash photolysis of the title compounds in each case leads to formation of a “tricoordinate” intermediate RhClL2 (A) (more likely the solvated species RhClL2 S) which is capable of various competitive reactions with substrates in solution. Picosecond techniques indicate complexity even in the formation of this intermediate. Subsequent reactions of A are strongly dependent on the nature of L as well as of the medium. For L = PPh3, rapid recapture of A by CO and competitive dimerization are the observable reactions regardless of solvent. However, for L = PMe3 activation of solvent benzene and cyclohexane by reversible C-H oxidative addition appears predominant in the absence other substrates. The PTo13 (To1 = p-tolyl) complex shows intermediate behavior by activating benzene but not cyclohexane.© 1990 IUPAC