Simulation of porphyrin-ethanol solvate shell by DFT method

Abstract

Theoretical studies on porphyrin-ethanol solvates containing from 1 to 8 ethanol molecules have been carried out by density functional theory (DFT) calculations using hybrid (B3LYP) and meta-GGA (M06-L) functionals. It was established that porphirin molecule can be considered as two centered protones acceptor. Specific solvation is at the base of porphyrin-(EtOH)n interactions and results in a distortion of macrocycle planar structure. The nucleophilic solvation energy of the porphirin pyrrole demonstrates dependence on the number of molecules in the ethanol solvate, being the highest for the first two ethanol molecules and decreasing with ethanol association in the solvation shell. Results obtained by this way are in good agreement with data derived from 1H NMR.

Push‐Pull Effect at Formation of Sitting‐Atop Metal‐Porphyrin Complex in Solvating Media: H‐Bonding and Electrostatic Repulsion

“…This conclusion is consistent with the above‐mentioned influence of the distortion degree of the porphyrin macrocycle on the reactivity, which is extremely dependent on the composition of the solvation shell [36] . Indirect confirmation of the decisive contribution of macrocycle distortion is given in, [41] where a comparative study of the kinetics of porphyrin complexation with zinc and cadmium acetates in polymer membranes based on cellulose acetate and model low‐molecular solvents was carried out.…”

“…The solvation of the porphyrins ground state was studied earlier in a number of works [35,36,39] . The interaction of alcohol with porphyrin leads to the formation of complexes with a hydrogen bond and to distortion of the initial planar molecule.…”

“…The mechanism and kinetics of porphyrins complexation should substantially depend on the specific solvation of not only the ground state of the macrocycle, but also that of the intermediate ‐ SAT complex [36] . Difficulties in the experimental assessment of its solvation are associated with the impossibility of its isolation from the reaction medium.…”

“…These assumptions [33–35] are confirmed by the data of quantum chemical calculations [36] indicating the maximum distortion of the initially flat structure of the macroring during the formation of the 1 : 2 porphyrin – ethanol H‐complex, and hence the achievement of the maximum possible reactivity of the macroheterocycle in this solvation state [36] . The acoplanarity of two cycles ‐ pyrrole and pyrrolene ‐ is a consequence of the donor‐acceptor interaction of alcohol molecules and nitrogen atoms in the central cavity.…”

Tetrahydroxyphenyl porphyrin membrane: a high-sensitivity optical waveguide gas sensor for NO2detection

“…Moreover, these molecules show strong absorption in the visible region and emission of more than 600 nano-wavelength in the fluorescence spectrum [16,17]. In nature, porphyrins, in the form of metal complexes, exist in heme, chlorophyll, vitamin B12, and other living tissues, and participate in the transmission of oxygen and photosynthesis [18,19]. These features and characterizations make them feasible as sensitive materials for detecting oxygen, volatile organic liquids, harmful inorganic gases, and excess metal ions [20].…”