H. Ishida - Cochemist

Temperature dependence of one-dimensional hydrogen bonding in morpholinium hydrogen chloranilate studied by 35Cl nuclear quadrupole resonance and multi-temperature X-ray diffraction

Co-reporter:Yasuhiro Tobu, Ryuichi Ikeda, Taka-aki Nihei, Kazuma Gotoh, Hiroyuki Ishida and Tetsuo Asaji

Physical Chemistry Chemical Physics 2012 vol. 14(Issue 35) pp:12347-12354

Publication Date(Web):23 Jul 2012

DOI:10.1039/C2CP41241A

The temperature dependence of 35Cl NQR frequencies and the spin–lattice relaxation times T1 has been measured in the wide temperature range of 4.2–420 K for morpholinium hydrogen chloranilate in which a one-dimensional O–H⋯O hydrogen-bonded molecular chain of hydrogen chloranilate ions is formed. An anomalous temperature dependence of the NQR frequencies was analyzed to deduce a drastic temperature variation of the electronic state of the hydrogen-bonded molecular chain. The hydrogen atom distribution in the O⋯H⋯O hydrogen bond is discussed from the results of NQR as well as multi-temperature X-ray diffraction. Above ca. 330 K, the T1 showed a steep decrease with an activation energy of ca. 70 kJ mol−1 and with an isotope ratio 37Cl T1/35Cl T1 = 0.97 ± 0.2. The orientational change of the z axis of electric field gradient tensor in conjunction with the hydrogen transfer between adjacent hydrogen chloranilate ions is suggested as a possible relaxation mechanism.

Crystal structure of 4'-O-methylalpinumisoflavone at 90K

Co-reporter:R. Kingsford-Adaboh;E. Ahiano;B. Dittrich;H. Okamoto;M. Kimura

Crystal Research and Technology 2006 Volume 41(Issue 7) pp:728-733

Publication Date(Web):1 JUN 2006

DOI:10.1002/crat.200510656

4′-O-Methylalpinumisoflavone crystals which hitherto had been difficult to crystallize for X-ray diffraction analyses have been obtained from a demethylated product of O, O-dimethylalpinumisoflavone. The structural and conformational features of the crystal measured at 90 K are reported and compared with previously reported work of O,O-dimethylalpinumisoflavone and 5-O-methyl-4′-O-(3-methyl-but-2-en-1-yl) alpinumisoflavone. Each of these compounds is characterized by a six membered ring that is further fused to a benzopyrone isoflavone moiety resulting in a tricyclic ring system. This six membered ring shows a half-chair conformation in all the molecules studied, with the ring in the title compound showing the least Cremer-Pople puckering amplitude Q and shorter inter and intramolecular contacts. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Structure and phase transition in bis(pyrrolidinium) hexachlorometallates, (C4H8NH2)2MCl6 (M=Sn, Te and Pt), studied by X-ray diffraction, 35Cl NQR and DSC

Co-reporter:H. Ishida, Y. Furukawa, S. Sato, S. Kashino

Journal of Molecular Structure 2000 Volume 524(1–3) pp:95-103

Publication Date(Web):13 June 2000

DOI:10.1016/S0022-2860(99)00456-1

Single crystal X-ray diffraction, 35Cl nuclear quadrupole resonance (NQR) and differential scanning calorimetry (DSC) measurements were taken for bis(pyrrolidinium) hexachlorometallates, (C4H8NH2)2MCl6 (M=Sn, Te and Pt). A solid–solid phase transition was observed at 150(1), 159(1) and 134(1) K for stannate, tellurate and platinate, respectively. 35Cl NQR signals were observed in stannate and platinate, both of which showed a two-line spectrum in the high-temperature phase and a three-line spectrum in the low-temperature phase. The high-temperature phases of the three complexes were found to be isostructural with each other belonging to the space group C2/m (#12). The C4H8NH2+ and MCl62− ions are connected by N–H⋯Cl hydrogen bonds forming parallel sheets in the crystals. Disorder of the cation ring appears in these high-temperature phases. Semi-empirical MO calculations were performed to estimate the stable structure of the pyrrolidinium ion.

Temperature dependence of one-dimensional hydrogen bonding in morpholinium hydrogen chloranilate studied by 35Cl nuclear quadrupole resonance and multi-temperature X-ray diffraction

Co-reporter:Yasuhiro Tobu, Ryuichi Ikeda, Taka-aki Nihei, Kazuma Gotoh, Hiroyuki Ishida and Tetsuo Asaji

Physical Chemistry Chemical Physics 2012 - vol. 14(Issue 35) pp:NaN12354-12354

Publication Date(Web):2012/07/23

DOI:10.1039/C2CP41241A

The temperature dependence of 35Cl NQR frequencies and the spin–lattice relaxation times T1 has been measured in the wide temperature range of 4.2–420 K for morpholinium hydrogen chloranilate in which a one-dimensional O–H⋯O hydrogen-bonded molecular chain of hydrogen chloranilate ions is formed. An anomalous temperature dependence of the NQR frequencies was analyzed to deduce a drastic temperature variation of the electronic state of the hydrogen-bonded molecular chain. The hydrogen atom distribution in the O⋯H⋯O hydrogen bond is discussed from the results of NQR as well as multi-temperature X-ray diffraction. Above ca. 330 K, the T1 showed a steep decrease with an activation energy of ca. 70 kJ mol−1 and with an isotope ratio 37Cl T1/35Cl T1 = 0.97 ± 0.2. The orientational change of the z axis of electric field gradient tensor in conjunction with the hydrogen transfer between adjacent hydrogen chloranilate ions is suggested as a possible relaxation mechanism.