Synthesis and Characterization of Six-Coordinate "3 + 2" Mixed-Ligand Oxorhenium Complexes with the o-Diphenylphosphinophenolato Ligand and Tridentate Coligands of Different N and S Donor Atom Combinations

A series of octahedral six-coordinate oxorhenium(V) mixed ligand complexes containing the common [ReO- (L)]2+ fragment (L ) o-OC6H4P(C6H5)2] have been synthesized and characterized. Hence, it was shown that the [ReO(L)]2+ moiety can accommodate a variety of tridentate ligands containing a central amine group amenable to deprotonation and different combinations of lateral groups, such as ethylamine, substituted ethylamine, ethylthiol, and ethylthioether arms. In particular, by reaction of equimolar amounts of the pertinent HLn ligands with the [(n-C4H9)4N][ReOCl3(L)] precursor in refluxing acetonitrile/methanol or dichloromethane/methanol mixtures, the following series of [ReO(Ln)(L)]+/0 oxorhenium(V) complexes has been generated: ReO{[N(CH2CH2NH2)2][o- OC6H4P(C6H5)2]}Cl (1); ReO{[(C2H5)2NCH2CH2NCH2CH2S][o-OC6H4P(C6H5)2]} (2); ReO{[(CH2)4NCH2CH2- NCH2CH2S][o-OC6H4P(C6H5)2]} (3); and ReO{[C2H5SCH2CH2NCH2CH2S][o-OC6H4P(C6H5)2]} (4). The complexes are closed-shell 18-electron oxorhenium species, which adopt octahedral geometries both in solution and in the solid state, as established by conventional physicochemical techniques including multinuclear NMR and single-crystal X-ray diffraction analyses.