A series of Cp*Rh and Cp*Ir complexes of various nitrogen and oxygen donor ligands were synthesized and characterized. Mono, bi and tetradentate ligands were used to synthesize mononuclear and dinuclear complexes. Schiff base derivatives of picolinic hydrazine and 5-aminoquinoline were used in thesynthesis of complexes 1–8. Among the ligands used for complexation, L1 and L2 act as bidentate, L3 as monodentate and L4 as tetradentate in forming the corresponding complexes. All the complexes were characterized by spectroscopic techniques and the structures of complexes 2, 3, 5 and 7 were unambiguouslycharacterized by single crystal X-ray crystallography. Complexes 2 and 7 were found to have π-π stacking interactions and solvent to complex interactions, respectively. Metal-mediated deprotonation of N-H and monodentate binding of nitrogen are attributed to the formation of neutral complexes whereas ionic complexes are formed by (N,O) bonding.

Heterocyclic compounds containing pyrrole and indole-fused isocoumarins were obtained from a one-pot synthesis via annulations of N-heterocyclic carboxylic acids and alkynes with N^O chelate ruthenium(II)complex, [RuCl(PySO₃)(p-cymene)] (PySO₃ = 2-pyridinesulfonate) in the presence of Cu(OAc)₂H₂O. The reaction proceeds efficiently in DMF but can also be performed in other solvents such as dichloroethane, ^tAmOH, and water. The annulations reaction is regioselective when performed 1-methylpyrrole-2-carboxylic acid with 1-phenyl-1-propyne.