Conformational studies. Part II. Crystal and molecular structures of 3-bromo-, 3-chloro-, and 4-bromo-2′-nitrochalcone
Abstract
The crystal structures of 3-bromo-, 3-chloro-, and 4-bromo-2′-nitrochalcone have been solved from 0kl, partial three-dimensional, and zonal data respectively. Unlike other chalcones so far analysed and 4-bromo-2′-nitro-chalcone the first two compounds crystallise in the transoid conformation of the enone system. 3-Chloro- and 4-bromo-2′-nitrochalcone exhibit short oxygen⋯carbon contacts (2·58 and 2·64 Å) between the nitro- and carbonyl groups.