Reorientational Motion of Hydrogen Bonded Octahedral Complex Anions in Hydrazinium Hexachlorostannate(IV), (N2H5)2SnCl6, as Studied by 35Cl NQR Spin-Lattice Relaxation Measurements

Abstract

AbstractThe temperature dependences of NQR frequencies and spin-lattice relaxation times, T1Q, of 35Cl in (N2H5 ) 2SnCl6 were measured. Four NQR signals distributed in a fairly wide frequency range were observed, the lowest-frequency line exhibiting an anomalous positive temperature coefficient. The highest-frequency line showed a steep temperature dependence. These results could be interpreted by considering the intermolecular interaction between CI and - NH2 in N2H5+ . Below ca. 250 K, T1Q of the upper three signals exhibited a gradual decrease upon heating, explainable by lattice vibrations, while a shallow T1Q minimum, ascribable to the modulation of electric quadrupole interaction, was observed at ca. 110K for the lowest-frequency signal. The reorientation of [SnCl6]2- was elucidated to be highly anisotropic, in that it reorients about one of the CI-Sn-Cl axes much more frequently than about the other two axes. The activation energies were determined to be 62 and 94 kj mol -1 for the respective reorientations.