Potential energy surfaces of the Cu2+(NH3)n

The solvation effects is important in understanding the process to form a solution. Although several processes take place in solution, these effects on the structures of molecular clusters have received less attention. In this work, we have investigated for the first time, the effects of solvent (ammonia) on the structures, energetics, dative bond and hydrogen bond networks of the Cu2+(NH3)n=1−10 clusters. We have explored thoroughly the potential energy surfaces (PESs) at the M06-2X/6-31++G(d,p) level of theory in the solvent phase (represented by a dielectric continuum medium) and compare them with the structures of the computed Cu2+(NH3)n=1−10 clusters in the gas phase. For the description of the dielectric continuum medium, we used the integral equation formalism of the polarized continuum model (IEF-PCM). Besides, we have reported the binding and clustering energies per ammonia molecule. It emerges from this study that the hexa- and penta-coordinated structures are located on the global minimum of the energies of PESs of the Cu2+(NH3)n=1−10 clusters. The stability rules of the Cu2+ ion are better respected in the solvent phase than in the gas phase. Both the distances of the dative bonds are shorter and hydrogen bonds are longer in the solvent phase than those in the gas phase. All the mentioned differences between the results in the solvent phase and those in the gas phase must thank to the polarization of the medium. For the prediction of binding and clustering electronic energy, a function is fitted and used to predict these energies at saturation in the solvent phase and those in the gas phase. In the solvent phase the value of binding energy is -2465kJmol−1 and -17 931kJmol−1 in the gas phase. Similarly, the values of clustering energies are -25kJmol−1 and -379kJmol−1 in solvent phase and in gas phase respectively. This large difference in the predicted energies in the solvent phase with respect to those in the gas phase is due to the fact the metal-ligand interaction is the influence by the implicit solvent in the solvent phase. In fact, the solvent phase may be better predicted considering the clusters in the dielectric continuum medium than those in the gas phase because of the polarization of the medium. NBO analysis confirms energetics analysis. We therefore recommend this fitted function for the study of such clusters.