Design and synthesis of photoactive molecules based on metal dithiolenes

This work reports on the design, synthesis and characterization of some homoleptic and heteroleptic d8 metal (Ni, Pd, Pt) dithiolene complexes. Chapter 1 provides the background required to properly design metal dithiolenes exhibiting desired properties. Chapter 2 describes the synthesis & characterization of homoleptic radical monoanionic complexes showing multi-properties. Among these, a platinum complex prepared using a ligand containing a quinoxaline moiety connected through a dithieno bridge to the dithiolene core, shows unusual anti- Kasha solution proton dependent luminescence. The interaction of protons with these complexes is described with a view to understand their photo/electrocatalytic behaviour in aqueous acidic systems. Photocatalytic preliminary experiments on noble metal free homoleptic Ni-complex for hydrogen production from aqueous acidic solutions are described. Chapter 3 describes design, synthesis and characterization of chiral/achiral heteroleptic d8 metal dithiolene complexes, suitable as donor-metal-acceptor chromophores for 2nd order NLO applications. It describes how with the presence or absence of acid (protons) in solutions of complexes can afford two switchable chemical forms (having different electronic properties) which can possibly display contrast in their NLO response. It also describes, by inclusion of chirality in the acceptor ligand, a non-centrosymmetric arrangement of molecules in crystalline medium to preserve NLO response in the bulk. Moreover, the unusual proton dependent dual luminescent properties of some of these complexes are described. Lastly Chapter 4 contains conclusions, perspectives and appendices for this work.