Hydrogen bonding and pi-stacking interactions in the zipper-like supramolecular structure of the monomeric cadmium(II) complex [Cd(pyterpy)(H2O)(NO3)(2)] (pyterpy=4 '-(4-pyridyl)-2,2 ': 6 ',2 ''-terpyridine)

Abstract

The reaction of pyterpy with an excess of cadmium(II) nitrate yields the novel mononuclear complex [Cd(pyterpy)(H2O)(NO3)(2)]. The crystal structure shows to the Cd(II) centre in a seven-coordinate environment and the molecular units behaving as supramolecular nodes. These neutral nodes are connected through aromatic pi-stacking interactions concerted with O-H...N(4-pyridyl) and O-H...O(nitrate) hydrogen bonds to give couples of parallel linear strips assembled in a zipper-like motif. The infinite strips are oriented in the same direction and each one interact weakly with their neighbors by means of C-H...O hydrogen bonds to form the crystal. The supramolecular product is highly insoluble in the most common organic solvents and water, but soluble in dimethyl sulfoxide where the intermolecular interactions are broken.