MODIFICATION OF CRYSTAL PACKING AND MOLECULAR CONFORMATION VIA SYSTEMATIC SUBSTITUTION

Article abstract of DOI:10.1016/S0040-4020(01)90250-9

Variations in molecular conformation and crystal packing are investigated by systematically altering the substituents on a molecule which has two degrees of conformational freedom.The crystal structures of the heterodisubstituted benzylideneanilines (BA's),p-chloro-N-(p-chlorobenzylidene) aniline (BrCl) and p-bromo-N-(p-chlorobenzylidene) aniline (ClBr) have been determined.The conformations of the two molecules are different from each other but are similar to those found in the crystal structures of the homodisubstituted derivatives with which they are isomorphous: p-bromo-N-(p-bromo-benzylidene) aniline (BrBr) and the orthorombic form of p-chloro-N-(p-chloro-benzylidene)aniline (ClCl) respectively.Because of this isomorphous relationship it is concluded that the substituent on the benzylidene ring plays a crucial role in determining the packing mode of the structure.