A laser ash photolysis, matrix isolation, and DFT investigation of (η6-C6H5Y)Cr(CO)3 (Y = NH2, OCH3, H, CHO, or CO2CH3)

The quantum yield for arene displacement from ( g6- C6H5Y) Cr( CO) 3 was measured in 1,1,2- tri. uorotrichloroethane ( Y = NH2, OCH3, H, CHO, or CO2CH3). Values of 0.24, 0.27, 0.15, 0.17, and 0.32 were obtained respectively ( kexc. = 355 nm). These values are signi. cantly higher than those measured for photoinduced arene loss in hydrocarbon solvents using the same excitation wavelength. Laser. ash photolysis of ( g6C6H5Y) Cr( CO) 3 in 1,1,2- tri. uorotrichloroethane ( kexc. = 355 nm) resulted in the rapid formation (< 10 ns) of Cr( CO) 6. Matrix isolation experiments on ( g6- C6H5Y) Cr( CO) 3 ( Y = H or CHO) at 12 K in CH4 or CO- doped CH4 matrixes using monochromatic irradiation con. rmed the presence of two discrete excited states, one leading to CO- loss and the other to arene- loss. The results correlate with the calculated electron drift in the excited state derived from density functional theory and time dependent density functional theory calculations. (c) 2008 Elsevier B. V. All rights reserved.