Second-shell thermochemistry for hydration of strontium dications as determined by threshold collision-induced dissociation and computations

This work reports a continuation of the guided ion beam tandem mass spectrometer (GIBMS) study of the threshold collision-induced dissociation of Sr2+(H2O)(x). The present study measures OK hydration energies for Sr2+(H2O),, where x = 7-9, which can be added to those previously measured for x = 1-6. The full range of these complexes is also examined theoretically employing B3LYP/SDD/def2-TZVP and B3LYP/DHF/def2-TZVPP geometry optimizations with additional B3LYP, B3P86, M06, and MP2(full) single point energy calculations performed with the larger SDD/def2-TZVPP and DHF/def2-TZVPP basis sets, respectively. The transition between first and second hydration shells is explored from both experimental and theoretical findings. Neither experimental nor theoretical results are completely consistent with a single coordination number for the first hydration shell at 298 K, but rather suggest mixed coordination numbers ranging from 6 to 8 water molecules. (C) 2017 Elsevier B.V. All rights reserved.