title: Hydrogen bonding in 1,2-diazine-chloranilic acid (2 : 1) studied by a 14N nuclear quadrupole coupling tensor and multi-temperature X-ray diffraction.
abstract: Protons involved in the H-bond system in 1,2-diazine-chloranilic acid (2 : 1) are assumed to be in jumping motion in the double-minimum potential corresponding to the two extreme electronic states of O-H...N and O-...H-N+. 14N nuclear quadrupole coupling constants were determined by 1H-14N nuclear quadrupole double resonance. Assuming that the observed coupling constants are result of a fast exchange of the two extreme electronic states, the coupling constants for each state were estimated by use of the equilibrium populations of the two extreme states determined from multi-temperature X-ray single-crystal diffraction. It was suggested that not only the population but also the electron distribution of the extreme electronic states itself changes with temperature.
authors.affiliation: Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia.
authors.forename: Janez
authors.initials: J
authors.lastname: Seliger
authors.forename: Veselko
authors.initials: V
authors.lastname: Zagar
authors.forename: Kazuma
authors.initials: K
authors.lastname: Gotoh
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ishida
authors.forename: Akiko
authors.initials: A
authors.lastname: Konnai
authors.forename: Daiki
authors.initials: D
authors.lastname: Amino
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Asaji