Photochemistry of (η6-anisole)Cr(CO)3 and (η6-thioanisole)Cr(CO)3: evidence for a photoinduced haptotropic shift of the thioanisole ligand, a picosecond time-resolved infrared spectroscopy and density functional theory investigation.
The photochemistry of (η(6)-anisole)Cr(CO)(3) and (η(6)-thioanisole)Cr(CO)(3) was investigated by picosecond time-resolved infrared spectroscopy in n-heptane solution at 298 K. Two independent excited states are populated following 400 nm excitation of each of these complexes. An excited state with some metal-to-CO charge-transfer character is responsible for the CO-loss process, which is slow compared to CO-loss from Cr(CO)(6). Observed first order rate constants of 1.8 × 10(10) s(-1) and 2.5 × 10(10) s(-1) were obtained for the anisole and thioanisole complexes, respectively. The second excited state has metal-to-arene charge transfer character and results in a haptotropic shift of the thioanisole ligand. DFT calculations characterized the excited states involved and the nature of the haptotropic shift intermediate observed for the thioanisole species.
School of Chemical Sciences, Dublin City University, Dublin 9, Ireland.
Ian P
IP
Clark
Michael W
MW
George
Gregory M
GM
Greetham
Emma C
EC
Harvey
Conor
C
Long
Jennifer C
JC
Manton
Hazel
H
McArdle
Mary T
MT
Pryce
D002857:Chromium / Q000737:chemistry*; D006843:Hydrocarbons, Chlorinated / Q000737:chemistry*; D008024:Ligands; D055668:Photochemical Processes; D010777:Photochemistry; D011789:Quantum Theory; D013055:Spectrophotometry, Infrared; D013440:Sulfides / Q000737:chemistry*; D013997:Time Factors
D006843:Hydrocarbons, Chlorinated; D008024:Ligands; D013440:Sulfides; D002857:Chromium; C093850:methylphenylsulfide