Synthesis and reactivity of homo-bimetallic Rh and Ir complexes containing a N,O-donor Schiff base

Binuclear complexes [{(η5-C5Me5)RhCl}2(μ-bsh)] (1) and [{(η5-C5Me5)IrCl}2(μ-bsh)] (2) containing N,N′-bis(salicylidine)hydrazine (H2bsh) are reported. The complexes 1 and 2 reacted with EPh3 (E = P, As) to afford cationic complexes [(η5-C5Me5)Rh(PPh3)(κ2-Hbsh)]PF6 (3), [(η5-C5Me5)Rh(AsPh3)(κ2-Hbsh)]PF6 (4), [(η5-C5Me5)Ir(PPh3)(κ2-Hbsh)]PF6 (5), and [(η5-C5Me5)Ir(AsPh3)(κ2-Hbsh)]PF6 (6) which were isolated as their hexafluorophosphate salts. Representative complexes 3 and 5 have been used as a metallo-ligand in the synthesis of binuclear complexes [(η5-C5Me5)RhCl(μ-bsh)Ru(η6-C10H14)Cl]PF6 (7) and [(η5-C5Me5)IrCl(μ-bsh)Ru(η6-C10H14)Cl]PF6 (8). The complexes under study have been fully characterized by analytical and spectral (FAB/ESI-MS, IR, NMR, electronic and emission) studies. Molecular structures of 1, 2, 3 and 5 have been determined crystallographically. Structural studies on 1 and 2 revealed the presence of extensive inter- and intra-molecular C–H···O and C–H···π weak bonding interactions. The complexes 1, 2, 3 and 5 moderately emit upon excitation at their respective MLCT bands.