Bidentate phosphinophenol ligand: synthesis and characterization of oxo and phenylimido rhenium(V) complexes of 2-diisopropylphosphinophenol

Abstract Six-coordinate, monosubstituted and disubstituted phosphinophenol complexes ReYX 2 (PPh 3 )(P∼O) and ReYX(P∼O) 2 (Y=O, NPh; X=Cl, Br, I) were obtained by reacting 2-diisopropylphosphinophenol (P∼OH) with ReOX 3 (PPh 3 ) 2 and Re(NPh)X 3 (PPh 3 ) 2 in toluene. A mixture of the monosubstituted and disubstituted complexes ReYX 2 (PPh 3 )(P∼O) and ReYX(P∼O) 2 was precipitated when the reactions were performed with a 2:1 ligand to metal ratio. Excess ligand (4 equiv.) was needed to obtain quantitatively the disubstituted complexes. 1 H and 31 P{ 1 H} NMR show that all monosubstituted and disubstituted complexes exist as single isomers with a trans -P,P ‘twisted’ octahedral geometry, the site trans to the multiple bond being filled by the oxygen donor of one P∼O ligand. The compounds were also characterized by microanalysis, IR and mass spectrometry.