Secondary bonding interactions in some di- and trihaloanilinium halides

摘要

Six solvent-free structures of di- and trihaloanilinium halides are presented. All involve clearly defined hydrophilic regions built up from classical hydrogen bonding systems. The 2,4-dibromo-, 2,6-dichloro-, 2,4,6-trichloro- and 2,4,6-tribromoanilinium derivatives form ribbon structures involving annelated R-4(2)(8) rings with NH2 donors (two hydrogens from the positively charged NH3 groups) and halide acceptors. The 2,5-dibromo- and 2,4,5-trichloro derivatives form layers with two types of ring, R-4(2)(8) and R-8(4)(16). All structures also involve other secondary interactions (C-H... X hydrogen bonds and/or X...X contacts, X = halogen), some of which link the ribbons or layers into a second or third dimension. The shortest X...X contacts generally involve the anions. In the 2,4-dibromo, 2,4,6-trichloro and tribromo derivatives, somewhat more extensive halogen aggregates (triangles, angled X-3 or X-4 chains) are formed between neutral halogens. In two appendices, the packing patterns of (I) the disordered structure 3,4,5-trichloroanilinium chloride and (II) the known structures of unsubstituted anilinium halides are briefly presented. [References: 9]