NQR, NMR, and X-ray crystal structure studies of [4-C2H5-C6H4NH3]2MBr4 (M=Zn, Cd)
Author:
Ishihara Hideta1, Honda Hisashi2, Svoboda Ingrid3, Fuess Hartmut3
Affiliation:
1. Faculty of Culture and Education , Saga University , Saga 840-8502 , Japan 2. Graduate School of Nanobioscience , Yokohama City University , Kanazawa-ku, Yokohama 236-0027 , Japan 3. Materials Science , Technische Universität Darmstadt , 64287 Darmstadt , Germany
Abstract
Abstract
The crystal structure of [4-C2H5-C6H4NH3]2ZnBr4 (1) has been determined at 150(2) K: triclinic, P1̅, a=724.82(2), b=1194.20(4), c=1322.26(4) pm, α=74.151(3), β=80.887(3), γ=80.434(3)°, and Z=2. There are two crystallographically independent cations in the unit cell of 1: one has its benzene ring perpendicular to the crystallographic a axis of the unit cell and the other one has its benzene ring perpendicular to the c axis. These cations are alternatingly located along the c axis and form organic layers, and the ZnBr4 anions form inorganic layers in between. Zn–Br···H–N hydrogen bonds are formed between cations and anions. In accordance with the crystal structure, four nuclear quadrupole resonance (NQR) lines of 81Br were observed. The temperature dependence of the 81Br NQR frequencies between 77 and 320 K shows a peculiar feature which is not due to a structural phase transition. The measurement of 13C nuclear magnetic resonance spectra at around T=340 K indicates a redistribution of cations. The temperature dependence of 81Br NQR frequencies and differential thermal analysis measurements show that [4-C2H5-C6H4NH3]2CdBr4 (2) undergoes a structural phase transition at around 190 K.
Publisher
Walter de Gruyter GmbH
Subject
General Chemistry
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