Synthesis spectroscopic and DFT studies of some benzimidazole and benzothiazole derivatives

Abstract

Benzimidazole, benzothiazole and benzoxazole compounds and their derivatives having azole newlinemoieties are biologically active and are extensively used in pharmaceutical industry. newlineBenzimidazoles/benzothiazoles scaffolds have also been widely used as and#61552;and#8722;spacers and newlinedonor/acceptor units. The lone pair electrons and conjugated structures of these heterocyclic molecules assist in tuning of electronic properties enabling their use in devices like dye sensitized solar cells, organic light emitting diodes etc. However, the design and synthesis of organic ligands newlinefor these applications is still a challenging task. Though we have made an effort in this direction fabricating a dye sensitized solar cell with benzimidazole based sensitizer, the moderate Stokes shift and efficiency prompted us to tune these molecules and improve their electronic properties. Considering that some of the benzimidazole/benzothiazole fluorophores possessing metal-ion newlinechelating properties and having hydrogen donor-acceptor sites in close proximity play vital role in sensor and bioimaging applications, we have designed and synthesized novel fluorophores for newlinemetal ion sensing applications. Since most of the available literature shows studies on fluorophores with single excited state intramolecular proton transfer sites or dual proton transfer sites with symmetrical structures, we have considered investigating fluorophores having asymmetrical newlinestructures and proton donating sites. In this perspective, we have synthesized and conducted spectroscopic and density functional theory studies on some novel fluorophores based on benzimidazole/benzothiazole Schiff bases and the details are presented in this thesis. Chapter 1 gives an introduction to the benzimidazole/benzothiazole heterocycles and the different photophysical and chemical phenomena involved. A brief literature survey in support of our studies is presented in Chapter 2. Chapter 3 gives a brief description of the experimental methods newlineand techniques used in our work.