A new polymorph of 1,4-bis(imidazol-1-ylmethyl)benzene dihydrate and its hyrogen-bonded fivefold interpenetrated CdSO4 network

Single crystals of a new polymorph of 1,4-bis(imidazol-1-ylmethyl)benzene dihydrate (bix center dot 2H(2)O), C14H14N4 center dot 2H(2)O, have been obtained by the hydrothermal method. The asymmetric unit is composed of two independent half-bix molecules, one on an inversion center and one on a twofold axial site, and two water molecules. The disordered water molecules link into discrete tetrameric water units via two O-H center dot center dot center dot O hydrogen bonds, forming planar R-4(4)(8) rings. These tetrameric water units and bix molecules are further linked by two O-H center dot center dot center dot N hydrogen bonds into a three-dimensional network in which an R-20(20)(106) hydrogen-bonded ring is observed. These large rings lead to the formation of a fivefold interpenetrated network. If both the tetrameric water units and the bix molecules can be regarded as connected nodes, one single three-dimensional net can then be rationalized as a CdSO4 network. This study indicates that topological methodology can be applied in some cases in order to understand the inherent characteristics of some hydrogen-bonded supramolecular assemblies.