Isaev, S. D.; Zhalnina, G. G.; Murzinova, Z. N., Journal of Organic Chemistry USSR (English Translation), 1988, vol. 24, # 12, p. 2358 - 2364
作者:Isaev, S. D.、Zhalnina, G. G.、Murzinova, Z. N.、Ivzhenko, T. V.、Yurchenko, A. G.
DOI:——
日期:——
Pseudosymmetry and phase transition in dimethyl 2,3-bis(tricyclo[3.3.1.1<sup>3,7</sup>]dec-2-ylidene)butanedioate
作者:Jan W. Bats、Marc A. Grundl、A. Stephen K. Hashmi
DOI:10.1107/s0108270101003845
日期:2001.5.15
The crystal structure of the title compound, C26H34O4, shows a reversible phase transition at about 178 K. The structure of the high-temperature phase contains two independent molecules related by pseudosymmetry elements. Cooling through the phase-transition temperature results in a doubling of the c axis. The low-temperature structure contains four independent molecules related by pseudosymmetry elements. The phase transition results in a rearrangement of some weak intermolecular C-H . . . O interactions. The number of very weak C-H . . . O interactions, with H . . . O distances between 2.8 and 2.9 Angstrom, is increased in the low-temperature structure.
Dimethyl dispiro[tricyclo[3.3.1.1<sup>3,7</sup>]decane-1,2′-bicyclo[1.1.0]butane-4′,1′′-tricyclo[3.3.1.1<sup>3,7</sup>]decane]-1′,3′-dicarboxylate, a strain-enhanced bicyclo[1.1.0]butane with a very short intramolecular C—H...H—C contact
作者:Jan W. Bats、Michael Bolte、Marc A. Grundl、A. Stephen K. Hashmi
DOI:10.1107/s010827010100004x
日期:2001.4.15
The title molecule, C26H34O4, shows a very short repulsive intramolecular C-H . . .H-C contact, with an H . . .H distance of only 1.71 Angstrom. The flap angle phi of the bicyclo[1.1.0]butane group is widened to 131.23 (8)degrees. Both methylene C atoms show tilt angles of 6.1 degrees. Bond lengths in the fused cyclopropane rings range from 1.501 (1) to 1.542 (1) Angstrom and are influenced by pi interactions with the carboxylate substituents.