The relative stability of macrotricyclic metal complexes in M(II)-thiocarbohydrazide-acetone (M = Mn, Fe, Co, Ni, Cu, Zn) ternary systems according to the data of quantum-chemical calculations

The B3LYP hybrid method of density functional theory with the 6–31G(d) basis set was used to calculate the optimum geometry and standard thermodynamic parameters of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II) macrotricyclic complexes with MN2S2 and MN4 chelate nodes. The calculations were performed using the Gaussian 98 package. Such complexes could in principle appear because of temperature processes between gelatin-immobilized hexacyanoferrates(II) of the corresponding M(II) metal ions, thiocarbohydrazide, and acetone. For all the M(II) metals considered, complexes with MN2S2 chelate nodes were stablest. The standard Gibbs energies ΔfG298° values were positive for all the complexes specified.