Half-sandwich pentamethylcyclopentadienyl group 9 metal complexes of 2-aminopyridyl ligands: Synthesis, spectral and molecular study

Abstract

The reaction of [Cp*M(µ-Cl)Cl]2 (M = Rh, Ir) with 2-aminopyridyl based ligands lead to the formation of mononuclear neutral complexes of general formula [Cp*MCl2(L)] {where L1 = 2-aminopyridine, L2 = 2-amino-3-picoline, L3 = 2-amino-3-nirtopyridine, and L4 = 2-amino-3-pyridine carboxyaldehyde}. The complexes have been characterized by FT-IR, UV-Vis, 1H-13C NMR and mass spectroscopic methods. X-ray crystallographic studies of the complexes have shown typical piano-stool geometry around the metal centre in which 2-aminopyridyl ligand acts as an N-monodentate ligand and the amino functionality is not involved in metal coordination. The intra/intermolecular arrangement is due to hydrogen bonding. A new series of pentamethylcyclopentadienyl rhodium/iridium complexes with 2-aminopyridyl ligands have been synthesized and characterized by spectral studies. The complexes have shown that piano-stool geometry around the metal center in which 2-aminopyridyl ligand acts as an N-mono-dentate ligand and the amino functionality is never involved in metal coordination.