We report herein a comparison of DFT, Møller-Plesset, and coupled cluster calculations of the proton dissociation energies of imidazole and N-methylacetamide in the presence of the zinc divalent cation. Despite the MP2 calculation showing that the proton dissociation energy of the zinc-bound imidazole was 4 kcal/mol higher than that of the zinc-bound N-methylacetamide, all the higher-level Møller-Plesset, DFT, and coupled-cluster calculations revealed that the proton dissociation energy of the zinc-bound imidazole was 4-10 kcal/mol lower than that of the zinc-bound N-methylacetamide. The results support the reported hypothesis of imidazolate as a zinc ligand in proteins.
- Coordination chemistry
- Zinc proteins
ASJC Scopus subject areas
- Condensed Matter Physics
- Physical and Theoretical Chemistry