TY  - SER
AU  - Minaeva,Valentina A.
AU  - Baryshnikov,Gleb V.
AU  - Surovtsev,N.V.
AU  - Cherkasova,Olga P.
AU  - Tkachenko,L.I.
AU  - Karaush-Karmazin,Nataliya N.
AU  - Stromylo,E.V.
AU  - Minaev,Boris F.
TI  - Temperature effects in low-frequency Raman spectra of corticosteroid hormones
KW  - кортикостероиды
KW  - температурные эффекты
KW  - низкочастотные спектры
KW  - статьи в журналах
N1  - Библиогр.: 29 назв
N2  - Experimental Raman spectra of the corticosteroid hormones corticosterone and desoxycorticosterone are recorded at different temperatures (in the range of 30–310 K) in the region of low-frequency (15–120 cm−1) vibrations using a solid-state laser at 532.1 nm. The intramolecular vibrations of both hormones are interpreted on the basis of Raman spectra calculated by the B3LYP/6-31G(d) density functional theory method. The intermolecular bonds in tetramers of hormones are studied with the help of the topological theory of Bader using data of X-ray structural analysis for crystalline samples of hormones. The total energy of intermolecular interactions in the tetramer of desoxycorticosterone (−49.1 kJ/mol) is higher than in the tetramer of corticosterone (−36.9 kJ/mol). A strong intramolecular hydrogen bond O21-H⋯O=C20 with an energy of −42.4 kJ/mol was revealed in the corticosterone molecule, which is absent in the desoxycorticosterone molecule. This fact makes the Raman spectra of both hormones somewhat different. It is shown that the low-frequency lines in the Raman spectra are associated with skeletal vibrations of molecules and bending vibrations of the substituent at the C17 atom. The calculated Raman spectrum of the desoxycorticosterone dimer allows one to explain the splitting and shift of some lines and to interpret new strong lines observed in the spectra at low temperatures, which are caused by the intermolecular interaction and mixing of normal vibrations in a crystal cell. On the whole the calculated frequencies are in a good agreement with the experimental results
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ER  -