Peculiarities of the interspecies interactions of metallocomplexes of structurally similar α,α-dipyrrolylmethene and porphyrin with organic solvents

It was revealed that the ML2 complexes (L- is the anion of 3,3′,5,5′-tetramethyl-4,4′-dibutyldipyrrolylmethene; M = Cu2+, Zn2+) are coordinatively unsaturated and, therefore, are able to coordinate electrondonor molecular ligands (pyridine and dimethylformamide (DMFA)) with the formation of ML2(Solv)2 solvates stable in solutions and in the solid phase. The thermal decomposition of the crystal solvates prepared by isothermal vaporization of the solvent from solutions of the oligopyrrole chelates in pyridine, DMFA, and benzene was studied. Thermogravimetric measurements made it possible to determine the composition and temperature of onset of the decomposition of the crystal solvates and the enthalpy of vaporization of the solvent from them. Calorimetry of dissolution was used to investigate the transfer of the chelates from benzene into pyridine and DMFA and the extracoordination of electron-donor molecular ligands in solutions. The overall energetic characteristics of the ML-Solv interspecies interactions in the crystal solvates and solutions exhibited a close correlation. A comparison of the properties of ML2 and their structural analogues, MPs (H2P is 2,8,12,18-tetramethyl-3,7,13,17-tetrabutylporphyrine), demonstrated how cyclization affect the coordination properties of oligopyrrole chelates.