FRAMEWORK ALTERATIONS IN PORPHYRINS BY PERIPHERAL FUSION AND CORE-MODIFICATION :- AN EXPERIMENTAL & COMPUTATIONAL STUDY

Abstract

Initial synthesis of porphyrins were driven by its biological significance. The synthesis of biologically relevant porphyrins are challenging owing to its complex substitution pattern. So, over the years, many artificial analogues of naturally occurring porphyrins were synthesized to study their intriguing properties which find applications in catalysis, tumour phototherapy and so on. Peripherally fused porphyrins are one such class where the external fragment fused to the porphyrin periphery imparts exceptional rigidity to the macrocyclic core. But the synthesis of peripherally fused porphyrins are challenging owing to the requirement of complex precursor molecules and methodologies to cyclize them. In this work, a novel strategy for the facile synthesis of fused porphyrin with heteroatom incorporation is explored. Detailed mechanistic analysis were done to elucidate the reason concerning low yields. Finally a reaction pathway was presented with improved yields. Also the fused tripyrranes that is formed as a byproduct in the reaction is found to undergo both metal chelation with characteristic signal changes and self-assembly behavior. Finally a theoretical work is presented that analyze the trends in core modification in porphyrins and sapphyrins.