BCSJ : Vol. 78 (2005) , No. 7 pp.1241-1245

H-Transfer Motions in an H-Bonded (Chloranilic Acid)-(1,3-Diazine) 1:2 Molecular Complex Studied by ³⁵Cl NQR and ¹H NMR

Ryuichi Ikeda¹⁾²⁾, Satoshi Takahashi²⁾, Taka-aki Nihei³⁾, Hideta Ishihara⁴⁾ and Hiroyuki Ishida⁵⁾

1) National Institute for Materials Science
2) Department of Chemistry, University of Tsukuba
3) Department of Chemistry and Biochemistry, Numazu College of Technology
4) Department of Chemistry, Faculty of Culture and Education, Saga University
5) Department of Chemistry, Faculty of Science, Okayama University

(Received January 11, 2005)

³⁵Cl NQR and ¹H NMR relaxation times (T_1Q, T_1H) were measured in a hydrogen-bonded (chloranilic acid)-(1,3-diazine) 1:2 molecular complex in a temperature range of ca. 100–300 K. NQR frequencies observed were explained by the monovalent (1−) ionic structure of chloranilic acid, implying partial H-transfer to diazine molecules. This H-transfer was shown to be dynamic by observing a single T_1H minimum at ca. 120 K. Two new relaxation processes observed by NQR in high-temperature range, but undetected by NMR, were shown to be H-transfer motions between differently charged states of chloranilic acid molecules.