Supramolecularly assembled decameric water cluster stabilized by dichromate anions in complex of Ni(II)

A new decameric water cluster in compound of [Ni (phen)3Cr2O7 · 5H2O] 1 (where phen = 1,10-phenanthroline) has been synthesized and structurally characterized by single-crystal X-ray diffraction. Thermogravimetry, infrared spectra, elemental analysis have also been used to characterize 1. The decameric water cluster consists of a non-planar eight-membered ring and two water molecules, and plays an important role in stabilizing the dichromate anions in 1. We believe that the unusual water structure demonstrated herein brings to light yet another novel mode of the cooperative association of water molecules, and this discovery is helpful in improving the modeling of some of unexplained properties of water.