ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Structure and Gas-Phase Stability of Zn(II)--Molecule Complexes

M. Smieško and M. Remko

Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Comenius University, SK-832 32 Bratislava

E-mail: remko@fpharm.uniba.sk

Received: 27 October 2004

Abstract: Density Functional Theory method at the B3LYP level with large “triple zeta” 6-311+G(d,p) basis set was used to study structural and thermodynamic parameters of complexes of bivalent zinc cation with selected ligands acting as Lewis bases: H₂CS, HNO₂, H₂NCHS, CH₃XH, CH₃X, HCXXH, HCXX⁻, imidazole, 1,3-oxazole, 1,3-thiazole, Y—PH(==O)O⁻, Y—SHO₂ where X = O, S and Y = H, OH, NH₂. Ligands binding to zinc bivalent cation via sulfur atom, due to its “soft” (polarizable) character, generally showed higher interaction enthalpies in comparison with corresponding oxygen analogues with “hard” (less polarizable) character. This rule applies for both monodentate and bidentate ligands. Derivatives of phosphonic acid exhibit higher interaction enthalpies and lower entropies than structurally related derivatives of sulfonic acid. In the series of 5-membered heterocyclic ligands the interaction enthalpies and Gibbs energies decrease in the order imidazole, 1,3-thiazole, 1,3-oxazole.

Full paper in Portable Document Format: 595a310.pdf

Chemical Papers 59 (5) 310–315 (2005)