PROPERTIES OF CLOSED-SHELL, OCTAHEDRAL, MULTIPLY-CHARGED HEXAFLUOROMETALLATES MF(6)(3-), M=SC, Y, LA, ZRF62-, AND TAF6-

Properties of multiply-charged hexafluorometallates MF(6)(3-), M = SC, Y, La, ZrF62-, and TaF6-, have been examined at the SCF, MP2, and Bec ke3LYP levels of theory using the SBKJ pseudopotentials and extended o ne-electron basis sets. For MF(6)(3-), M = SC, Y, La, our results sugg est a different assignment of vibrational transitions than those quote d by Nakamoto(1) and recorded by von Becker et al.(2) For the series o f isoelectronic complexes, we document that the discrepancy between th e theoretical gas phase vibrational frequencies and those measured in condensed phase experiments increases as the Becke3LYP HOMO binding en ergies become more positive. The frequencies of stretching modes measu red in condensed phase experiments are systematically higher than thos e calculated for the gas phase anions. We suggest that a partial charg e transfer from the multiply-charged anions to countercations is respo nsible for the stiffening of vibrational modes in condensed phase envi ronments. The vertical electron detachment energies were determined at the outer valence Green's function, MP2, and B3LYP levels. The bindin g energies of hexafluorometallates with respect to the energies of ato mic ions were also calculated and only a small contribution of the ele ctron correlation effects was found.