Chapter I contains a short introductory survey of literature.

Chapter II deals with methods of preparation of ligands, metal complexes and their physicochemical data.

Chapter III deals technique and experimental data of spectrophotometric such as near and far infra red spectra, ultravoilet and visible spectra, magnetic measurement and conductometric studies on complexes.

Chapter IV embodies the studies on complexes of l,2,4-triazine-3(5) thione with Magnicium(II) ions. The ligand forms very stable diamagnetic tetraheadral, neutral as well as cations complexes in which bonding of ligand occurs through thione form. The presence of I-, N03-, C03- ions in complexes satisfied primary as well as secondary valency of magnicium ions.

&ugr;MgO bands are obtained at 465cm-1 in far I.R. spectra, &ugr;MgI bands are also observed at 445 & 260 cm-1 in [Mg (TTH) Pyl2] complexes.

Chapter V contains discussion of results of Pb(II) complexes with 4-Amino 3-Hydrazino-5-Mercapto 1,2,4-Triazine and reasonable conclusions regarding structure and nature of bonding have been stablised. This ligand also formed stable diamagnetic distorted tetraheadral structure with Pb(II) ions in which bonding of the ligand occurs through thione sulphur resulting unprotonated bonding.

Chapter VI- Studies on results of Sn(II) and Bi(III) complexes with 1,2,4-trizine-3,5-thione have been described in chapter VI. The ligand formes very stable diamagnetic distorted octahedral complexes with Bi(III) ions which are fair soluble in D.M.F.. This ligand forms polymeric nonelectrolytic tetrahedral structure of Sn(II) ions. The bonding of ligand occurs through thione sulphur atom. The ultra violet UV spectra of Bismuth complexes exhibit very strong band between 305-350nm, assigned due to n → pi* transition.