Thermodynamics of Solution of Hemato- and Deuteroporphyrins in N,N-Dimethylformamide

Abstract

This paper focuses on the results of the first accurate study of thermodynamics of solution for two blood porphyrins in the model of a protein-like environment–liquid N,N-dimethylformamide (DMF) in the physiological temperature range. The solubility of hematoporphyrin dimethylether dimethylester (HDEDE) and deuteroporphyrin dimethylester (DDE) in DMF has been obtained from (288 to 318) K. Free energies, enthalpies, entropies, and heat capacities of solution have been computed from solubility data and compared with those obtained from the previously reported calorimetric data via the Gibbs–Helmholtz equation. We have shown that for the solutes studied it is more correct to compute thermodynamic functions from the temperature dependence of the enthalpy and solubility/activity at the reference temperature. This approach allows to reproduce qualitatively both free energies of solution and solubility of porphyrins for the physiological temperature range.

Thermodynamics of solution of proto- and mezoporphyrins in N,N-dimethylformamide

“…Equations (1) and (2) indicate that dissolution of both porphyrins is accompanied by the unfavorable enthalpy change. This unfavorable enthalpy is found to be strongly temperature dependent, which is very similar to the behavior of deuteroporphyrin [5]. Heat capacities of solution for PDE and MDE are nearly identical H(17-1)), À4.14 (br.…”

“…The agreement between experimental and computed by equation (3) quantities is rather well. For most soluble DDE and HDEDE [5] the agreement is slightly better that may be explained both by some underestimation of solubility values at the reference temperature and a stronger tendency of PDE and MDE to associate in DMF. The latter may lead to the deviation of activity coefficients from the unity (see figure 3).…”

“…Chemicals were prepared and purified by the similar way as in our previous studies [5,[7][8][9]. The structure and purity of both porphyrins were proved with the elemental analysis, thin-layer chromatography, absorption and NMR-spectra.…”

“…Recently [5], we have studied thermodynamics of solution of two blood porphyrins ex. hematoporphyrine dimethylether dimethylester (HDEDE) and deuteroporphyrine dimethylester (DDE) in the model of intrinsic surface of (globular proteins + liquid DMF) [6].…”

Solubilities of 5,10,15,20-Tetraphenylporphyrin and 5,10,15,20-Tetraphenylporphyrin Manganese(III) Chloride in Binary Ethanol + Water Solvent Mixtures

“…To better understand the dissolution process of TPP and TPPMnCl in ethanol + water solvent mixtures, the thermodynamic parameters of solution such as dissolution enthalpy Δ sol H 0 (J·mol –1 ), dissolution entropy Δ sol S 0 (J·mol –1 ·K –1 ), Gibbs free energy Δ sol G 0 (kJ·mol –1 ), and isobaric heat capacity Δ sol C p 0 (J·mol –1 ·K –1 ) should be derived from the experimentally determined solubilities by using the Clark–Glew equation ,, and assuming that the values of Δ sol C p 0 are temperature-independent for the temperature range studied. , The Clark–Glew equation is written as where x is the mole fraction of solute, R is the gas constant, θ is the reference temperature, T is the experiment temperature, and Δ sol H θ 0 , Δ sol G θ 0 , and Δ sol C pθ 0 are the dissolution enthalpy, Gibbs free energy, and isobaric heat capacity at reference temperature, respectively.…”