B, Ramachandra BhatH. C, Sampath Kumar2020-08-052020-08-052014https://idr.nitk.ac.in/handle/123456789/14361Transition metal complexes have become an integral part of nonlinear optics. The design of technologically useful metal complexes poses a continuous challenge for inorganic chemists. Keeping this in view, the present thesis addresses three major areas. First, to design and develop transition metal complexes using ligands with extensive π- conjugation. Second, to synthesize and characterize all the complexes by established techniques like Elemental analysis, FT-IR spectroscopy, UV-Vis spectroscopy, Single crystal XRD and NMR spectroscopy. Lastly, to evaluate the nonlinear optical activity of the complexes using techniques like Z-scan technique and Optical Kerr Gate method and thereby establishing a relationship between the complex structure and optical nonlinearity. All the complexes exhibited third-order optical nonlinearity. The Fe(II), Ni(II) and Zn(II) complexes of 1,2-diaminobenzene and 2-hydroxynaphthaldehyde and Co(II), Ni(II) and Zn(II) complexes of 3,4-diaminobenzophenone and 2- hydroxynaphthaldehyde displayed a two-photon absorption. On the other hand, Ni(II), Cu(II) and Zn(II) complexes of Schiff base ligands of dimethylamino benzaldehyde and thiosemicarbazide and Cu(I) complex with 1,10-phenanthroline and triphenylphosphine exhibited three-photon absorption mechanism. The ionic liquid tagged Schiff base metal complex also revealed effective two photon absorption with good third-order optical response. The nonlinear optical study on the complexes revealed encouraging results which can act as a base for any further improvement and their usage as optical limiters.enDepartment of ChemistryCoordination complexesSchiff base complexesnonlinear opticsthird-order nonlinearityZ-scan techniqueThesis