The irreversible crystal transformation of a novel Cadmium(II) supramolecular complex containing planar tetrameric water cluster

A new cadmium complex [CdL2(CH3COO)2] · 3H2O (1) has been synthesized by the reaction of 2-aminobenzimidazole (L) with cadmium acetate in an aqueous solution, and structurally characterized by single crystal X-ray diffraction and FT-IR spectra. Cyclic planar tetrameric water clusters with C2h symmetry are observed to be encapsulated in the 3D open supramolecular architecture of 1 by hydrogen bonds interactions. Interestingly, 1 can convert irreversibly into single crystal 1a formulated [CdL2(CH3COO)2] by losing its lattice water molecules at room temperature. Strong intermolecular N–H ⋯ O hydrogen bonds and aromatic rings π–π stacking interactions assemble 1a into another 3D interdigitated supramolecular network.