C–H ⋯ O hydrogen bonding. Part II. The crystal and molecular structure of o-chlorobenzoylacetylene

Abstract

The crystal structure of o-chlorobenzoylacetylene has been determined by Patterson, minimum function, and Fourier methods, and extensively refined by least-squares methods using three-dimensional data. The crystals are monoclinic, space group P2₁/c, with four molecules in a cell of dimensions a= 3·97, b= 12·35, c= 15·87 Å, β= 98·4°. The final discrepancy factor, R, is 0·092 and the atomic parameters reveal intermolecular C–H ⋯ O hydrogen bonds (3·212 ± 0·009 Å) linking ethynyl C–H groups to neighbouring carbonyl oxygen atoms. The molecule is significantly non-planar. The plane of the exocyclic ethynylcarbonyl group makes an angle of 7·1° with that of the benzene ring.