Crystal structure of trans-dicarbonylbis(dimethylphenylphosphine)(N-phenylsalicylideneaminato)rhenium(I) and mer-trichloro(dimethylphenylphosphine)(N-phenylsalicylideneaminato)rhenium(IV). Comparison of ReI, ReIII, ReIV, and ReV complexes with the salicylideneaminato ligand and reaction mechanisms

Abstract

The crystal structures of trans-[Re^I(CO)₂(psal)(PMe₂Ph)₂](1)(psal =N-phenylsalicylideneaminate) and mer-[Re^IVCl₃(psal)(PMe₂Ph)](2), have been determined from single-crystal diffractometer data and refined to R factors of 0.029 and 0.020. Crystal data are: a= 16.857(3), b= 10.788(3), c= 17.269(5)Å, β= 105.32(2)°, space group P2₁/n, Z= 4 for (1) and a= 7.981(2), b= 10.868(2), c= 13.917(1)Å, α= 99.63(1), β= 81.23(2), γ= 108.41(2)°, space group P, Z= 2 for (2). Both compounds display octahedral co-ordination and a general comparison of their bond distances with similar octahedral complexes of rhenium in its Re^III and Re^V oxidation states has been carried out. Differences are mainly interpreted in terms of trans influence and Pearson's hard–soft acid–base theory. Some aspects of the reaction mechanisms of formation of Re^V, Re^IV, Re^III, and Re^I complexes with bidentate Schiff bases are also considered on the basis of structural data.