3-Oxocyclobutanecarboxylic acid: hydrogen bonding in a small-ring γ-keto acid

Georgia Efthimiopoulos,Hugh W Thompson,Roger A Lalancette

doi:10.1107/s1600536809003961

Georgia Efthimiopoulos, Hugh W Thompson + Show 1 more

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https://doi.org/10.1107/s1600536809003961

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Abstract

The title ketocarboxylic acid, C5H6O3, is the smallest carboxycyclanone to have its crystal structure determined. It adopts a chiral conformation, by rotation of its carboxyl O atoms away from the plane of skeletal symmetry that passes through the carboxyl carbon and both atoms of the ketone carbonyl. The four-membered ring is non-planar, with a shallow fold of 14.3 (1)° along a line connecting the two α-carbons of the ketone group. In the crystal, the molecules are linked by centrosymmetric hydrogen-bond pairing of ordered carboxylic acid groups [O⋯O = 2.6392 (12) Å and O—H⋯O = 175.74 (15)°], yielding two different sets of dimers, related by by a 21 screw axis in c, in the cell. A C—H⋯O interaction is also present.

Highlights

The title ketocarboxylic acid, C5H6O3, is the smallest carboxycyclanone to have its crystal structure determined. It adopts a chiral conformation, by rotation of its carboxyl O atoms away from the plane of skeletal symmetry that passes through the carboxyl carbon and both atoms of the ketone carbonyl
The molecules are linked by centrosymmetric hydrogen-bond pairing of ordered carboxylic acid groups [OÁ Á ÁO = 2.6392 (12) Aand O—HÁ Á ÁO = 175.74 (15)], yielding two different sets of dimers, related by by a 21 screw axis in c, in the cell
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x, y+1/2, −z+3/2

Summary

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The title ketocarboxylic acid, C5H6O3, is the smallest carboxycyclanone to have its crystal structure determined. It adopts a chiral conformation, by rotation of its carboxyl O atoms away from the plane of skeletal symmetry that passes through the carboxyl carbon and both atoms of the ketone carbonyl. The four-membered ring is non-planar, with a shallow fold of 14.3 (1) along a line connecting the two -carbons of the ketone group. The molecules are linked by centrosymmetric hydrogen-bond pairing of ordered carboxylic acid groups [OÁ Á ÁO = 2.6392 (12) Aand O—HÁ Á ÁO = 175.74 (15)], yielding two different sets of dimers, related by by a 21 screw axis in c, in the cell.

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