Photochemistry of cyclopentadienylmolybdenum and cyclopentadienyltungsten carbonyl halide complexes

Article abstract of DOI:10.1021/ic50208a022

The primary photochemical process for η⁵-C₅H₅M(CO)3X complexes (M = Mo, X = Br or I; M = W, X = Cl, Br, or I) at 366 or 436 nm is dissociation of a carbon monoxide ligand. Irradiations of benzene solutions containing triphenylphosphine lead stereospecifically to cis-(η⁵-C₅H₅)M(CO)₂(PPh ₃)X. Quantum yields vary as a function of irradiation wavelength (Φ₃₆₆ > Φ₄₃₆), central metal (Φ_Mo > Φ_W) and halogen (Φ_Cl > Φ_Br > Φ_I) but are relatively insensitive to PPh₃ concentration. The substituted complexes η⁵-C₅H₅Mo(CO)₂(PPh₃)X undergo cis ? trans isomerization and ligand-exchange reactions leading to η⁵-C₅H₅Mo(CO)(PPh₃)₂X and η⁵-C₅H₅Mo(CO)₃X.