Thermal studies of some non-aqueous and aqueous porphyrins

Abstract

A precursor of non-aqueous porphyrin i.e. a free-base tetra phenyl porphyrin (TPP) was synthesized. This was then subjected to sulphonation in such a way that sodium salt of sulphonic acid groups were substituted at the para position (4-position) of four phenyl rings in TPP to get tetra sodium meso-tetra (p-sulphonatophenyl) porphyrin (TPPS4). Further, Co sup(2+) was inserted in TPP and TPPS4 and all compounds were characterized by UV- visible spectroscopy, IR spectroscopy and sup(1)H NMR spectroscopy. Subsequently, these compounds viz. TPP, CoTPP, TPPS sub(4) and CoTPPS sub(4) were subjected to TG-DSC analysis in synthetic air from ambient temperature to 800 degrees C. When sulphonic acid groups were substituted at the para-positions on the four phenyl rings of the aqueous porphyrins, it was observed that their thermal stability was reduced in comparison with non-aqueous porphyrins.