Thermochemistry of solution of methylpheophorbide a, dioxidine and their conjugate in chloroform from 298.15 K to 318.15 K

Abstract

This paper focuses on the study of thermochemistry of solution and transfer of potential hydrophobic photosensitizers, viz. 9-ethenyl-14-ethyl-21-(methoxycarbonyl)-3-{(O-methylcarbamoyl)ethyl}-4,8,13,18-tetramethyl-20-oxo-phorbine (Methylpheophorbide a, comp. 1), [3-(hydroxymethyl)-1-oxido-4-oxoquinoxalin-4-ium-2-yl]methanol (Dioxidine, comp. 2) and their conjugate 9-ethenyl-14-ethyl-3-{[2-(3-hydroxymethyl)]-1-oxido-4-oxoquinoxalin-4-ium-2-methyleneoxy}carbamoyl}ethyl)-4,8,13,18-tetramethyl-20-oxo-phorbine (Conjugate, comp. 3), in liquid chloroform (CHCl3) and N,N-dimethylformamide (DMF) between the temperatures of 298.15 K and 318.15 K. The standard enthalpies and heat capacities of solution as well as partial molar heat capacities of these species and some non-electrolytes modeling their side-chains have been computed from experimental enthalpies of solution and compared with previously reported quantities to highlight several important features of solvation of potential drugs in H-donor and H-acceptor media.