Conformational diversity of symmetric dimer mesogens, α,ω-bis(4,4′-cyanobiphenyl)octane, -nonane, α,ω-bis(4-cyanobiphenyl-4′-yloxycarbonyl)propane, and -hexane in crystal structures

Autor:	Akiko Nakao, Kayako Hori, Hirokazu Toriumi, Mizue Iimuro
Rok vydání:	2004
Předmět:	Biphenyl Dimer Organic Chemistry Crystal structure Analytical Chemistry Inorganic Chemistry chemistry.chemical_compound Crystallography chemistry Propane Molecule Nonane Conformational isomerism Spectroscopy Octane
Zdroj:	Journal of Molecular Structure. 699:23-29
ISSN:	0022-2860
DOI:	10.1016/j.molstruc.2004.05.003
Popis:	The crystal structures of the title compounds show a variety of molecular conformations: a twisted chain conformation to one side and biphenyl moieties with highly different twisted angles (8.0(3) and 31.0(2)°) in the octane (I-8), two largely different conformers in the nonane (I-9) with and without twofold rotation symmetry in the space group of P3121 in the trigonal system, a twisted conformation in the propane (II-3), and the all-trans conformation with the inversion center in the hexane (II-6). Bent molecules of odd members and straight molecules of even ones form wavy and straight stackings, respectively, in imbricated structures. The twisted conformers of I-8, I-9, and II-3 are compared with the hypothetical all-trans conformers using semi-empirical MO calculation. In I-8, another crystalline phase appears below 10 °C, the structure of which is energetically very similar to the structure determined at room temperature in this study.
Databáze:	OpenAIRE
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