Intensity-dependent decarbonylation dynamics in Cr(CO)6·(CH3OH)n heteroclusters at 280 nm

Femtosecond pump/probe studies of ultrafast decarbonylation and solvent dynamics of Cr(CO)6·(CH3OH)n heteroclusters with respect to pump intensity at 280 nm are presented. The dynamics changes significantly when increasing pump intensity. In contrast to sequential decarbonylation at low pump intensity, Cr(CO)5, which is formed from Cr(CO)6 (1T1u) after ejection of CO on the timescale of our femtosecond pulses, absorbs an additional pump photon at higher intensities. This species yields further fragments from a highly excited state on an ultrafast timescale. The picosecond dynamics of the solvated fragments formed involves solvent cluster loss and evaporation by coupling of vibrational molecular modes to cluster modes.