Structural Changes in Macrocycles of Tetrathio-Substituted 1,8-Dioxa-, 1,8-Dithia-3,6,10,13-Tetraazacyclotetradecane and 1,3,5,8,10,12-Hexaazacyclotetradecane upon the Complexation with 3d M(II) Ions according to Density Functional Theory Calculations

Abstract

Quantum-chemical DFT OPBE/TZVP method with the Gaussian09 program package have been used to calculate bond angles in the macrocycles of 1,8-dioxa-3,6,10,13-tetraazacyclotetradecanetetrathione-4,5,11,12, 1,8-dithia-3,6,10,13-tetraazacyclotetradecanetetrathione-4,5,11,12, and 1,3,5,8,10,12-hexaazacyclotetradecanetetrathione-6,7,13,14 and their complexes with Cr(II), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II) ions with (NNNN) coordination of the donor sites of the ligand forming upon the complexation in the ternary M(II)–ethanedithioamide—formaldehyde and M(II)–ethandithioamide–2-thiapropanediol-1,3 systems and in the quaternary M(II)–ethanedithioamide—formaldehyde—ammonia system in gelatin-immobilized matrix implants. It has been noticed that the macrocycle is considerably distorted in both the macrocyclic compounds (this distortion can be quantitatively characterized by the degree of deviation of the macrocycle from coplanarity) and in their complexes (more than 60°). Depending on the nature of both the M(II) ion and the macrocyclic ligand, this distortion can become weaker or stronger.