Different hydrogen-bonding modes in two closely related oximes

Dutkiewicz, Grzegorz and Yathirajan, H. S. and Ramachandran, R. and Kabilan, S. and Kubicki, Maciej (2010) Different hydrogen-bonding modes in two closely related oximes. Acta Crystallographica Section C, 66 (6). O274-O278. ISSN 1600-5759

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Abstract

Two closely related oximes, namely 1-chloro\-acetyl-3-ethyl-2,6-diphenyl\-piperidin-4-one oxime, C\sb 21H\sb 23ClN\sb 2O\sb 2, (I), and 1-chloro\-acetyl-2,6-diphenyl-3-(propan-2-yl)piperidin-4-one oxime, C\sb 22H\sb 25ClN\sb 2O\sb 2, (II), despite their identical sets of hydrogen-bond donors and acceptors, display basically different hydrogen-bonding patterns in their crystal structures. While the mol\-ecules of (I) are organized into typical centrosymmetric dimers, created by oxime—oxime O—-H⋅sN hydrogen bonds, in the structure of (II) there are infinite chains of mol\-ecules connected by O—-H⋅sO hydrogen bonds, in which the carbonyl O atom from the chloro\-acetyl group acts as the hydrogen-bond acceptor. Despite the differences in the hydrogen-bond schemes, the —OH groups are always in typical \it anti positions (C—-N—-O—-H torsion angles of \it ca 180\circ). The oxime group in (I) is disordered, with the hydroxy groups occupying two distinct positions and C—-C—-N—-O torsion angles of approximately 0 and 180\circ for the two alternatives. This disorder, even though the site-occupancy factor of the less occupied position is as low as \it ca 0.06, is also observed at lower temperatures, which seems to favour the statistical and not the dynamic nature of this phenomenon.

Item Type:	Article
Subjects:	C Chemical Science > Chemistry
Divisions:	Department of > Chemistry
Depositing User:	LA manjunath user
Date Deposited:	09 Jul 2019 11:26
Last Modified:	09 Jul 2019 11:26
URI:	http://eprints.uni-mysore.ac.in/id/eprint/5021

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