title: Monoligand Zn(II) Complexes:  Ab Initio Benchmark Calculations and Comparison with Density Functional Theory Methodologies.
abstract: A systematic theoretical study on several models of Zn(II) complexes has been carried out employing both ab initio correlated wave function and density functional methods. The performance of five different functionals namely PW91, PBE, B3LYP, MPWLYP1M, and TPSS in the prediction of metal-ligand bond distances, binding energies, and proton affinities has been assessed comparing the results to those obtained with the MP2 and CCSD(T) wave function methodologies. Several basis sets ranging from double-ζ up to quintuple-ζ quality have been used, including the recently developed all-electron correlation consistent basis sets for zinc. It is shown that all the tested functionals overestimate both the metal-ligand bond distances and the binding energies, being that the B3LYP and TPSS functionals are the ones that perform the best. An analysis of the metal-ligand interaction energy shows that induction and charge-transfer effects play a prominent role in the bonding of these systems, even for those complexes with the less polarizable ligands. This finding highlights the importance of a correct description of the polarization of the monomers' charge densities by any theoretical method which aims to be applied to the study of Zn(II) complexes.
authors.affiliation: Departamento de Química Física y Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, 47005 Valladolid, Spain, Center for Biomolecules and Complex Molecular Systems, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 16610 Prague 6, Czech Republic, and Departamento de Química Física y Analítica, Facultad de Química, Universidad de Oviedo, 33007 Oviedo, Spain.
authors.forename: Víctor M
authors.initials: VM
authors.lastname: Rayón
authors.affiliation: Departamento de Química Física y Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, 47005 Valladolid, Spain, Center for Biomolecules and Complex Molecular Systems, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 16610 Prague 6, Czech Republic, and Departamento de Química Física y Analítica, Facultad de Química, Universidad de Oviedo, 33007 Oviedo, Spain.
authors.forename: Haydee
authors.initials: H
authors.lastname: Valdés
authors.affiliation: Departamento de Química Física y Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, 47005 Valladolid, Spain, Center for Biomolecules and Complex Molecular Systems, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 16610 Prague 6, Czech Republic, and Departamento de Química Física y Analítica, Facultad de Química, Universidad de Oviedo, 33007 Oviedo, Spain.
authors.forename: Natalia
authors.initials: N
authors.lastname: Díaz
authors.affiliation: Departamento de Química Física y Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, 47005 Valladolid, Spain, Center for Biomolecules and Complex Molecular Systems, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 16610 Prague 6, Czech Republic, and Departamento de Química Física y Analítica, Facultad de Química, Universidad de Oviedo, 33007 Oviedo, Spain.
authors.forename: Dimas
authors.initials: D
authors.lastname: Suárez