X-ray structure and investigation of molecular motions by dielectric, vibrational and 1H NMR methods for two organic-inorganic hybrid piperazinium compounds: (C4H12N2)2[Sb2Cl10]·2H2O and (C4H12N2)2[Sb2Br10]·2H2O

Abstract

Bis(piperazine-1,4-diium) decabromodiantimonate(III) dihydrate, (C4H12N2)2[Sb2Br10]·2H2O, (abbreviated as PSB) has been synthesized and characterized by single-crystal X-ray diffraction studies. The obtained results indicate that PSB is isostructural with a recently described chloride analogue, (C4H12N2)2[Sb2Cl10]⋅2H2O (PSC), crystallizing with R2MX5·nH2O stoichiometry and characterized by the discrete zero-dimensional anionic species. The crystal structure of PSB is described by monoclinic symmetry in a P21/n space group. Dielectric measurements (down to 25 K) and IR spectral analyses (measured over a broad temperature range) suggested a much more complicated phase situation below 80 K than for that of PSC. To verify and compare the molecular motions of the organic cations in both analogues, a proton magnetic resonance (1H NMR) technique was also applied.