%0 Journal Article
%A Bator, G.
%A Sawka-Dobrowolska, W.
%A Sobczyk, L.
%A Grech, E.
%A Nowicka-Scheibe, J.
%A Pawlukojc, A.
%A Wuttke, J.
%A Baran, J.
%A Owczarek, M.
%T 4,4'-, 5,5'- and 6,6' -dimethyl-2,2'-bipyridyls: the structures, phase transitions, vibrations and methyl group tunneling of their complexes with chloranilic acid
%J The journal of chemical physics
%V 135
%@ 0021-9606
%C Melville, NY
%I American Institute of Physics
%M PreJuSER-18307
%P 044509
%D 2011
%Z This work was supported by the Polish Ministry of Science and Higher Education (Project Register No. N N204 2497 34) and partially by the International Programme ZIBJ DUBNA 04-4-1069-2009/2010.04.29 (Decision No. 868/W-ZIBJ DUBNA/2010/0). This research project has been supported by the European Commission under the 7th Framework Programme through the Key Action: Strengthening the European Research Area, Research Infrastructures (Contract No. 226507 (NMI3)).
%X The crystal and molecular structures of 4,4(')- and 6,6(')-dimethyl-2,2(')-bipyridyl complexes with 2,5-dichloro-3,6-dihydroxy-p-benzoquinone (chloranilic acid, CLA) have been determined and compared with those of the complex with the 5,5(')-derivative, which is known to possess interesting antiferroelectric properties. In the crystalline state, all three compounds form hydrogen bonded chains with N(+)-H···O(-) and O-H···N bridges on both sides of the bipyridyl constituent. The comparison of three derivatives indicates that the N(+)-H···O(-) hydrogen bonds are shortest for the 5,5(')-dimethyl complex. The 4,4(')- and 6,6(')-derivatives do not show any ferroelectric feature. The 6,6(')-one is, however, characterized by a continuous phase transition, revealed in the differential scanning calorimetry, dilatometric, and dielectric characteristics. The tunneling splitting measured by neutron backscattering in the energy range ±30 μeV for the neat dimethyl bipyridyls and their complexes with CLA indicates that the different splittings are primarily due to the crystal packing effect and that charge transfer between interacting compounds plays only a minor role.
%K J (WoSType)
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:21806140
%U <Go to ISI:>//WOS:000293477300058
%R 10.1063/1.3613640
%U https://juser.fz-juelich.de/record/18307