Structural, thermal, and nmr studies of hexafluorides with organic cations

Abstract

Three new hexafluoro complexes are studied: (EDA)TiF6, (A)2- SiF6, and (Py)2TiF6 (EDA is the ethylenediamine ion, A is the aniline ion, and Py is thepyridine ion). These compounds are representatives of a wide family of crystals, which are prospective for practical and fundamental research but have been studied insufficiently. The structure of (EDA)TiF6 was solved by the single crystal X- ray diffraction method (at room temperature): space group A2/a, a =10.655, b =8.7081, c =7.9704 a, Β =95.032‡. For all compounds studied, thermal, dielectric, and NMR measurements have been performed. Thermal measurements indicate that (EDA)TiF6, (Py)2TiF6, and (A)2SiF6 have phase transitions at 130, 195,and 248 K;173, 230, and 288 K, respectively. The presence of a phase transition in (EDA)TiF6 was confirmed by dielectric measurements.1H and19F NMR spectra were recorded, and spin- lattice relaxation times T1 were measured in a wide range of temperatures. The NMR data are analyzed from the viewpoint of the nature of internal mobility in the crystals under analysis.