Photo- and thermal isomerization of (TP)Fe(CO)Cl-2 [TP = Bis(2-diphenylphosphinophenyl)phenylphosphine]

The title complex displayed structural flexibility via photo- and thermal-isomerization reactions between three isomers: (mer-TP)Fe (CO)Cl-2 (A), unsym-(fac-TP)Fe(CO)-Cl-2 (B), and sym-(fac-TP)Fe(CO)Cl-2 (C). Irradiation of A at RT with 525 nm light selectively produces B, while at 0 degrees C isomer C is formed with the intermediacy of B. UV-vis spectroscopy combined with TD-DFT calculations revealed the nature of the photoisomerization process. Kinetics of the thermal isomerization of C to B and B to A have been studied with P-31 NMR spectroscopy in CD2Cl2, and activation parameters were determined. Isomers A and B have been isolated and crystallographically characterized.