Cu²⁺ binding chalcogen-chalcogen bridges : a problematic case for DFT

Yannick Jeanvoine (1) , Riccardo Spezia (1)

1 LAMBE - Laboratoire Analyse et Modélisation pour la Biologie et l'Environnement

In this work, we have investigated the binding of Cu²⁺ with the simplest chalcogen–chalcogen bridge models, i.e. H₂O₂, H₂S₂ and H₂Se₂. Different functionals were used to calculate binding energies and electronic properties: the simple local spin density (SVWN), some GGA (BLYP and PBE), some meta-GGA (TPSS and VSXC), different hybrid-GGA, moduling also the percentage of Hartree–Fock on the exchange contribution (B3LYP, PBE0, B98, MPW1PW91, BHandH, BHandHLYP) and two new hybrid-meta-GGA (M05 and M05-2X) functionals. Results are compared with CCSD(T) calculations and, when available, with experimental data. DFT seems to provide very different results as a function of the chosen functional and the only almost uniform message is that results can be improved by modifying the contribution of Hartree–Fock exchange. In particular, changing progressively the weight of nonlocal Hartree–Fock exchange, we found that using a value of 45% we can minimize differences with respect to CCSD(T) calculations. Finally, we noticed that adding another ligand, and thus saturating the metal coordination sphere, energies for ligand exchange reactions are less dependent to the choice of the functional.

Mots clés: Chalcogen; CCSD(T) calculations; Hartree–Fock exchange on DFT

Domaines: Chimie-Physique [physics.chem-ph]

Yannick Jeanvoine, Riccardo Spezia. Cu²⁺ binding chalcogen-chalcogen bridges : a problematic case for DFT. Journal of Molecular Structure: THEOCHEM, 2010, 954 (1-3), pp.7-15. ⟨10.1016/j.theochem.2010.05.001⟩. ⟨hal-00511025⟩