Synthesis and kinetic studies of some model peptides

The thesis is mainly concerned with synthesis, kinetic studies and conformational analysis of some model peptides. We have compared the UV-Vis absorption spectra, the \(\textit {trans-to-cis}\) photoisomerization and the \(\it {cis-to-trans}\) thermal isomerization of azobenzene peptides with those of precursor 4,4´-diaminoazobenzene, 4,4´-dicarboxylic acid azobenzene and parent azobenzene. The thermal decay is exponential and follows the first-order kinetics in all the cases we have considered. Whatever the substituent is, the rate is always faster than that of parent \(\it {cis}\)-azobenzene. Our experimental work shows that the energy of activation is different from substituent to substituent and even from solvent to solvent. The chain elongations of both the push-push and pull-pull azobenzenes by amide group with alanine residues cause the rate reduction in all cases. The rate reduction of amide derivatives from push-push azobenzene is more significant than that of amide derivatives from pull-pull azobenzene