Structure, Spectroscopy, and Bonding within the Znq+−Imidazolen (q2= 0, 1, 2; n = 1−4) Clusters and Implications for Zeolitic Imidazolate3 Frameworks and Zn−Enzymes

International audienceUsing density functional theory (DFT) with dispersion correction and ab initio post Hartree-Fockmethods, we treat the bonding, the structure, the stability and the spectroscopy of the complexes betweenZnq+ and imidazole (Im), Znq+Imn (where q = 0, 1, and 2; n = 1-4). These entities are subunits of zeoliticimidazolate frameworks (ZIFs) and Zn-enzymes, which possess relevant roles in industrial and biologicaldomains, respectively. We also investigate the Imn (n = 2-4) clusters for comparison. For each species, wedetermine several new structures that were not found previously. Our calculations show a competitionbetween atomic metal solvation, either by s-type interactions or p-stacking type interaction, andhydrogen bonding (H-bonding). This results in several geometrical environments around the metal. Theseare connected with structural properties and the functional role of Zn cation within ZIFs and Zn-enzymes.Moreover, we show that the Zn2+Imn subunits do not absorb in the Vis domain, which may be related tothe photostability of ZIFs. Our findings are important for the development of new applications of ZIFsand metalloenzymes