Thermal stability of chlorophyll a derivatives containing hydrophilic groups

Abstract

Trends in thermal stability of aromatic macroheterocycles based of pheophorbide a and chlorin e₆ containing hydrophilic groups have been revealed by means of thermogravimetric analysis at 298–1223 K under inert atmosphere. Methylpheophorbide a and 13(1)-N-methylamide of chlorin e₆ are the most stable, the decomposition onset temperature being t_o 351 and 333°С. Their functional substitution leads t_o the reduction in thermal stability. Depending on the macrocycle structure the decrease in t_o can reach 20–200°С.