Molecular structures of (575)macrotricyclic 3d-metal chelates in M(II)–N-methylthiocarbohydrazide–hexanedione-2,5 according to density functional theory calculations

Abstract

The geometric parameters of the molecular structures and thermodynamic parameters of macrotricyclic M(II) (M = Mn, Fe, Co, Ni, Cu, Zn) complexes with an MN₂S₂ chelate core formed by the template reactions of the M(II) with N-methylthiocarbohydrazide H₃C–HN–HN–C(=S)–NH–NH₂ and hexanedione- 2,5 H₃C–C(=O)–CH₂–CH₂–C(=O)–CH₃ have been calculated by the DFT method with the Gaussian09 program package. The bond lengths, bond angles, and some nonbonded angles in these complexes have been determined. In all the complexes, the M(II) central ion is pseudotetrahedrally coordinated by the donor atoms of an inner-sphere tetradentate ligand; the (N₂S₂) group of the donor atoms is not planar. The additional seven-membered chelate rings show significant deviations from coplanarity (>60°). The noncoplanatiry of the five-membered rings is less pronounced.