Rhodium(I) carbonyl complexes with α-diimine ligands containing amino or hydroxy substituents

α-Diimines, RN:C(R′)C(R′):NR′′(LL) derived from glyoxal, GLL (R′=H) abbreviated as GAA (R= R′′=4-dimethylaminophenyl) or GHA (R= R′′=4-hydroxyphenyl), and derived from biacetyl, BLL (R′=Me) abbreviated as BDH (R=R′′= NH2), BOH (R=NH2, R′′=OH) react with carbonylrhodium(I) compounds to give different products depending on the imino substituents in the ligand and/or the solvent employed. The reaction of α-diimines bearing amino groups, such as GAA or BDH with [RhCl(CO)2]2 in acetone yields binuclear [RhCl(CO)2]2(μ-LL) while in CH2Cl2 ionic [Rh- (CO)2(LL)]+[RhCl2(CO)2]− species are obtained. In acetone [RhCl(CO)2]2(μ-GAA) exists as an equilibrium mixture between two different neutral binuclear species; [Rh(CO)2(BDH)]+ exists as a mixture of two species containing chelate or monodentate bonded diimine respectively. GAA or BDH react “in situ” with [RhCl(CO)(C2H4)]2 in benzene to yield tetracoordinated monocarbonylated [RhCl(CO)(LL)] compounds. α-Diimines (LL) bearing hydroxy groups, such as GHA or BOH react with [RhCl(CO)2]2 or “[RhCl(CO)(C2H4)]2” to give pentacoordinated dicarbonylated [RhCl(CO)2(LL)] compounds.