Physicochemical studies of metal complexes with N and S donor ligands

Abstract

This thesis describes the physico-chemical studies of metal complexes with nitrogen and sulphur donor ligands. Emphasis has been given to the synthesis and characterization of polyazamacrocycles and dithiocarbamato complexes of transition metal ions and Sn(IV). They have been characterized by FT-IR, NMR (1H, 13C and 119Sn), mass spectrometry and X-ray crystallography. In some cases they have been studied by TGA/DSC. Some of the ligands and their complexes have been tested for their antibacterial and antifungal activity. The thesis is divided into six chapters. The first chapter highlights the major advances in the area of transition metal ions and Sn(IV) with polyazamacrocycles and dithiocarbamates. It explores various chemical and biological applications of polyazamacrocycles and dithiocarbamates in general. Chapter 2 describes the synthesis of fourteen membered hexaaza macrocyclic complexes of the type [CuL]X2 and [CuL1]X2 [where L= 3,10-bisbenzyl- 1,3,5,8,10,12-hexaazacyclotetradecane and L1 = 3,10-bisbenzyl-6,13-dimethyl- 1,3,5,8,10,12-hexaaza-cyclotetradecane and X = ClO4and#1050691; (1, 4) SCN¯(2) and PF6¯ (3, 5)]. These air stable monometallic complexes have been synthesized by template assisted condensation reaction and characterized by spectral and X-ray crystallographic techniques. An attempt has been made to study the effect of anions on the gross geometry and chemical properties of the Cu(II) ion. Their crystal structure show axially elongated octahedral geometry with weakly coordinated anions. The macrocyclic cyclam adopts trans-III configuration with six- and five-membered chelate rings in chair and gauche conformation, respectively. It was also observed that in the solid state the arrangement of the coordination sphere is distorted octahedral whereas in solution, a square-planar structure is predominant.