Crystal Structure, NQR and DSC Studies of Tetrabromocadmates(II): [4-H2NC5H4NH]2CdBr4 · H2O and [2,3,5,6-(CH3)4C4N2H2]CdBr4

Abstract

Abstract 4-Aminopyridinium tetrabromocadmate(II) monohydrate (1) crystallizes in the orthorhombic space group Pbcm with a = 6.876(2), b = 14.089(2), and c = 18.845(2) Å , Z = 4, T = 296 K. In the crystal structure, a [CdBr4]2− anion, a 4-aminopyridinium cation, and a water molecule are alternately connected into chains by hydrogen bonds N-H···Br and O-H···Br. 2,3,5,6- Tetramethylpyrazinium tetrabromocadmate(II) (2) crystallizes in the orthorhombic space group P212121 with a = 14.640(12), b = 15.615(7), c = 6.686(5) Å , Z = 4, T = 296 K. In the crystal structure, a [CdBr4]2− anion and a 2,3,5,6-tetramethylpyrazinium cation are interconnected by bifurcated hydrogen bonds N-H· · ·2Br and form infinite chains. 81Br NQR spectra with three lines with an intensity ratio of 1 : 1 : 2 (77 K ≤ T ≤ ca. 325 K) and four lines with an intensity ratio of 1 : 1 : 1 : 1 (77 K ≤ T ≤ ca. 330 K) were observed for crystalline 1 and 2, respectively, which are consistent with the crystal structure data. DSC measurements showed the existence of thermal anomalies at high temperatures in both 1 and 2.