Topochemistry. Part XXX. Crystal and molecular structures of chalcone

Abstract

The crystal structure of benzylideneacetophenone (chalcone) has been solved from photographically recorded partial three-dimensional data by means of the SEARCH computer programme and refined to discrepancy indices R′= 0·017 and R= 0·055. The C–C and C–O bond lengths have been determined with estimated standard deviations of 0·009 A. The two essentially planar phenyl units are linked by a non-planar cisoid 1,3-enone bridge twisted about the C–C bond by 16·9°.The molecules are arranged in alternating layers related by the two-fold screw axis along [001]; no short (<4·3 A)CC contact exists.