DOI: 10.1080/00268976.2021.1933637  OpenAccess

Microsolvation of the Be-F bond in complexes of BeF₂, BeF₃^–1, and BeF₄^–2 with nH₂O, for n = 1–6

Ab initio MP2/aug’-cc-pVTZ calculations have been carried out to determine the structures and binding energies of complexes of BeF2, BeF3–1, and BeF4–2 with n H2O molecules, with n = 1–6. For each series of complexes with BeF2, BeF3–1, and BeF4–2, the binding energies increase as the number of water molecules increases, but the binding energies per intermolecular bond for complexes formed between BeF2 and BeF4–2 and nH2O decrease as the number of water molecules increases. The binding energies per bond of the BeF3–1 complexes show little dependence on the number of H2O molecules present. Intermolecular O-H … F hydrogen bonds (HB) stabilise all complexes of H2O with the beryllium bases except for BeF2:1H2O and BeF2:2H2O. Complexes of BeF2 are also stabilised by O … Be beryllium bonds (BeB) and O-H … O hydrogen bonds. EOM-CCSD calculations have also been performed to determine the spin–spin coupling constants. The one-bond coupling constants 1J(Be-F) increase as the Be-F distance decreases, and exhibit an excellent second-order correlation with that distance. 2hJ(O-F) coupling constants across O-H … F hydrogen bonds also exhibit a second-order dependence on distance. Coupling constants 1beJ(O-Be) and 2hJ(O-O) are found in complexes with BeF2 and exhibit a linear dependence on the Be-O and O-O distances, respectively.