Acta Cryst. (2007). E63, o2084-o2086  [ doi:10.1107/S1600536807013700 ]

(E)-(1-Oxoindan-2-ylidene)acetic acid: catemeric hydrogen bonding in an unsaturated -keto acid

M. D. Dufort, R. A. Lalancette and H. W. Thompson

Abstract: The title compound, C₁₁H₈O₃, displays catemeric aggregation, involving hydrogen bonds progressing from the carboxyl of one molecule to the ketone of a glide-related neighbor [OO = 2.6952 (12) Å and O-HO = 177.7 (16)°]. The molecule is highly planar and inherently achiral, but a slight conformational enantiomerism generated by the packing creates alternating conformational chirality in the chain units. Hydrogen-bonding chains, all aligned in the a-axis direction, occur in parallel counter-directional pairs related by centrosymmetry. Significant overlap of the aromatic rings occurs in the molecular stacking, at an average distance of 3.354 Å. Two C-HO=C close contacts exist.

Online 4 April 2007

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