Cocrystals of 2,6-dichloroaniline and 2,6-dichlorophenol plus three new pseudopolymorphs of their coformers.

The structures of cocrystals of 2,6-dichlorophenol with 2,4-diamino-6-methyl-1,3,5-triazine, C6H4Cl2O·C4H7N5, (III), and 2,6-dichloroaniline with 2,6-diaminopyrimidin-4(3H)-one and N,N-dimethylacetamide, C6H5Cl2N·C4H6N4O·C4H9NO, (V), plus three new pseudopolymorphs of their coformers, namely 2,4-diamino-6-methyl-1,3,5-triazine-N,N-dimethylacetamide (1/1), C4H7N5·C4H9NO, (I), 2,4-diamino-6-methyl-1,3,5-triazine-N-methylpyrrolidin-2-one (1/1), C4H7N5·C5H9NO, (II), and 6-aminoisocytosine-N-methylpyrrolidin-2-one (1/1), C4H6N4O·C5H9NO, (IV), are reported. Both 2,6-dichlorophenol and 2,6-dichloroaniline are capable of forming definite synthon motifs, which usually lead to either two- or three-dimensional crystal-packing arrangements. Thus, the two isomorphous pseudopolymorphs of 2,4-diamino-6-methyl-1,3,5-triazine, i.e. (I) and (II), form a three-dimensional network, while the N-methylpyrrolidin-2-one solvate of 6-aminoisocytosine, i.e. (IV), displays two-dimensional layers. On the basis of these results, attempts to cocrystallize 2,6-dichlorophenol with 2,4-diamino-6-methyl-1,3,5-triazine, (III), and 2,6-dichloroaniline with 6-aminoisocytosine, (V), yielded two-dimensional networks, whereby in cocrystal (III) the overall structure is a consequence of the interaction between the two compounds. By comparison, cocrystal-solvate (V) is mainly built by 6-aminoisocytosine forming layers, with 2,6-dichloroaniline and the solvent molecules arranged between the layers.