Water Molecular Motion and Hydrogen Bond in Paramagnetic [Cu(H2O)6][PtCl6] as Studied by Single Crystal 2H NMR

Abstract

The temperature and angular dependences of the 2H NMR spectrum were measured for single crystal [Cu(H2O)6][PtCl6]. (e2Qq/h, η) = (132 kHz, 0.72) were obtained for the D nucleus averaged by the fast 180° flip of the water molecule at 297 K. D1(236 kHz, 0.10) and D2(246 kHz, 0.09) were obtained for two unequal D nuclei of the water molecule at 133 K. Below Tc , at least three nonequivalent waters were found to exist. The jumping rate for the 180° flip of the water molecule (k) was obtained from the simulation of 2H NMR spectra at H0||[111] direction. The activation energy Ea and the jumping rate at infinite temperature were estimated from the temperature dependence of k to be 24kJmol-1 and 1 x 1013s-1