CONFORMATIONAL MOBILITY OF CHOLESTERYLE n-ALKOXYBENZOATES AT THE PHASE TRANSITIONS

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 Title: CONFORMATIONAL MOBILITY OF CHOLESTERYLE n-ALKOXYBENZOATES AT THE PHASE TRANSITIONS Creators: Vinijchuk, A. V.; Golovina, N. A.; Polishchuk, A. P.; Puchkovskaya, G. Issue Date: 1995 Publisher: Ohio State University Abstract: In this report IR spectra of cholesteryle n-aloxybenzoates homologes (n=1, 3-6, 110, 16) in 100-570 K temperature range have been studied and X-ray structural analysis of the crystals has been performed. On the base of interpreted spectra the IR-band, which are the most sensitive to phase transitions, were found. These are the esteric group vibrations $(1100-1120 cm^{-1}, 1240-1290 cm^{-1}, 1700-1740 cm^{-1})$ and the benezene ring stretching vibrations Q (C = C) $(1515 cm^{-1}, 1580 cm^{-1}, 1610 cm^{-1})$, It was found that in contrast to n-alkaonates of cholesterine, the methylene chains of all investigated homologues are melted in crystalline phase even at 100K. It is explained by the antiparallel packing of the AOBCh molecules in layers, when alkyl tail'' has a free space between the rigid volume steroid nucleus. By means of IR and X-ray techniques it was found that there are nonequivalent molecules, even in solid state, which differ from each other by angle between the planes of steroid nucleus and ester group. Description: Author Institution: Ukrainian Academy of Sciences, Prospect Nauki, 46, 252650 Kiev, Ukraine. URI: http://hdl.handle.net/1811/29953 Other Identifiers: 1995-FE-08