Confinement of unprecedented tetrahedral water tetramers inside 1D hydrophobic channels of metal–organic framework hosts

Two NbO frameworks are constructed by the reaction of Co(OAc)2·4(H2O)/Zn(OAc)2·2(H2O) with 1-(4-(1H-benzimidazol-1-yl)phenyl)butane-1,3-dione in the ratio of 1:2, in which they are isostructural and the NbO net exhibits a two-fold interpenetration featuring hexameric 1D channels. Theses channels are occupied by unprecedented tetrahedral tetramer water clusters.