Syntheses and characterization of new polydentate amide ligands with inorganic tin (II) and lead (II) ions

Abstract

Complexes of inorganic Sn(II) and Pb(II) with new ligands N0′,N″-bis(3-carboxy-1-oxopropanyl) 2-amino-N-arylbenzamidine (C₂₁H₂₁N₃O₆) and N′,N″-bis(3-carboxy-1-oxophenelenyl) 2-amino-N-arylbenzamidine (C₂₉H₂₁N₃O₆) have been synthesized and characterized by elemental analyses, vibrational spectra, electronic spectra, ¹H NMR spectra, TOF-mass spectra, thermal studies and X-ray powder diffraction studies. The infrared and ¹H NMR spectral data are in agreement with coordination of amide and carboxylate oxygen of the ligands giving a MO₄ tetrahedral chromophore. The elemental analyses and mass spectral data are consistent with the formation of ML complexes. Kinetic and thermodynamic parameters were computed from the thermal data using Coats and Redfern method, which confirm first order kinetics. X-ray powder diffraction determines the cell parameters of the complexes. Molecular structures of the complexes have been optimized by MM2 calculations and suggest a tetrahedral geometry around metal (II) ions.