Femtosecond Infrared Studies of the Dissociation and Dynamics of Transition Metal Carbonyls in Solution

• DOI: 10.1021/jp9618035
• Publication Date: 2002-07-26T04:43:48Z
• Authors: Tianquan Lian; Steven E. Bromberg; Matthew C. Asplund; Haw Yang; C. B. Harris
• Keywords: Bleach

The ultrafast dynamics of the dissociation M(CO)6 (M = Cr, W, Mo) in alkane solutions were studied by femtosecond IR spectroscopy. After UV photolysis at 295 nm, both bleach parent molecules and absorption pentacarbonyl intermediate probed with 240 fs time resolution. Oscillatory perturbed free induction decay signals before t 0 observed well characterized realistic parameters system. recovery found to be wavelength dependent, indicating that hot are formed is determined vibrational cooling time. measured percentage n-heptane less than expected value calculated from photosubstitution quantum yield measurements, suggesting initial faster our kinetics A1 mode region species have been probe formation nascent product. product rises an instrument response limited rate much fs. long this reflect A fast constant 300 present all wavelengths probed, its spectrum appears resemble early species. This decay, three different metal carbonyls, attributed geminate recombination photodissociated CO ligand after only one two collisions solvent cage.