Cadmium(II) and cobalt(II) complexes generated from benzimidazole-5-carboxylate: Self-assembly by hydrogen bonding and π-π interactions

Self-assembly of L− (HL=benzimidazole-5-carboxylic acid) from Cd(II) and Co(II) respectively by the layer-separating diffusion method at ambient temperature give rise to two new supramolecular architectures [(CdL2·H2O)·2CH3OH]n (1) and {[CoL2(H2O)2]·2H2O}n(2), both of which are stabilized by hydrogen bonding and the intermolecular π-π interactions. The former complex displays a remarkable 3-D structure with unusual channels born from the interlayer voids. The latter exhibits the 3-D structure consisting of 1-D zigzag chains. The thermal and fluorescence properties associated with their crystal structures have been measured, and complex 1 displays intense blue emission in the solid state.