Cyclometalated rhodium(III) and iridium(III) complexes containing amino acids as N,O-chelates

The synthesis of bis-cyclometalated aminocarboxylato complexes [M(α-aminocarboxylato)(ptpy)2] (M = Rh, 3, 4, 5; M = Ir, 6, 7, 8), ptpy = 2-(p-tolyl)pyridinato; aminocarboxylato = glycinato, l-alaninato, l-prolinato) from [{M(μ-Cl)(ptpy)2}2] (M = Rh, 1; M = Ir, 2) is described. The molecular structure of [Ir(l-alaninato)(ptpy)2] (7) was confirmed by a single-crystal X-ray diffraction study. Compound 7 crystallized from methanol-iso-hexane in the space group P21. For 7 the two diastereoisomers ΔIr, SC and ΛIr, SC were found crystallizing twice per unit. Absorption and emission spectra were recorded. The rhodium compounds are weak yellow-green and the iridium species strong green emitters.