Experimental and Theoretical Evaluation of the Structure and Properties of New Stannyl Complexes of Pyridine Amide Ligands

Abstract

Aims: Penta and tetra coordinated stannyl derivatives of N, N'-Bis(2-pyridyl)pyridine-2,6-dicarboxamide (H2L) and N-(pyridine-2-yl)picolinamide (HL1) have been synthesized. The structure of the complexes has been well established by Sn119 NMR and computational studies (GAUSSIAN 03 suit of programs). MESP and NBO studies have been carried out to understand different binding modes and properties of the complexes as well as ligands. The relative bond strengths have been estimated using the Wiberg bond index analysis. Study Design:  Experimental and computational. Place and Duration of Study: Department of Chemistry, University of Rajasthan, Jaipur, 2014. Methodology: The structure of the complexes has been analyzed by IR and NMR. Computational studies (GAUSSIAN 03 suit of programs) have been used to elucidate the structure of the newly synthesized complexes. Results: 119Sn NMR showed a pentacoordinate range for diamide complexes indicating coordination through the nitrogen of central pyridine ring in addition to amide nitrogens and tetracoordinate range for monoamide complexes confirming the formation of the products. The bonding properties have been confirmed by the computational calculations. Conclusion: A series of dialkyl/diphenyl and trialkyl/triphenyl derivatives of organo tin complexes containing amide functionality have been synthesized and their structural characterizations performed by different spectral techniques and computational analysis.