Question

Iron carbonyl cluster complexes with monophosphine ligands: synthesis, characterization, and crystal structure

Answer 1

Three new monophosphine-substituted iron carbonyl cluster complexes [(μ-PDT)Fe2(CO)5L] [(PDT = SCH2CH2CH2S, L = P(CH2Ph)3, 1; P(C6H11)3, 2; PPh2(PhMe-p), 3)], which can be regarded as active site mimics for [FeFe]-hydrogenase, have been prepared in 40–70 % yields by reactions of the parent complex (μ-PDT)Fe2(CO)6 (A) with monophosphine ligands in the presence of the decarbonylating agent Me3NO·2H2O. All three complexes were characterized by elemental analysis and spectroscopic techniques, as well as by X-ray crystallography for complex 1. The IR spectra of the complexes reveal that the electron-donating abilities of the different monophosphine ligands follow the order PPh2(PhMe-p) > P(C6H11)3 > P(CH2Ph)3.