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

alpha-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 alpha-diimines bearing amino groups, such as GAA or BDH with [RhCl(CO)(2)](2) in acetone yields binuclear [RhCl(CO)(2)](2)(mu-LL) while in CH2Cl2 ionic [Rh- (CO)(2)(LL)](+)[RhCl2(CO)(2)](-) species are obtained. In acetone [RhCl(CO)(2)](2)(mu-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. alpha-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.