The Pearson’s HSAB principle in the quantum-chemical model of formation of the MN2O2 or MN2S2 coordination node in the bischelates of Be(II) and Hg(II) with ambidentate ligands based on azomethines and their cyclic analogs

The density functional theory method (DFT) has been applied to investigate the competitive coordination upon formation of the bivariant (with respect to the coordination node composition; MN2O2 or MN2S2) isomers of Be(II) and Hg(II) bischelates based on thioxoindanone derivatives of azomethines, azines, and azoles. The simulation-revealed effects of the properties of the central metal atom and the composition of the ligating donor atoms on the relative stability of the complexes isomers (the MN2O2 or MN2S2 node) has been in agreement with the prediction based on the empirical Pearson’s hard and soft acids and bases (HSAB) principle.