Assembly of discrete linear (H2O)5 water cluster within an entangled two-dimensional coordination network

The coordination polymer {[Zn2(1,3-pda)2(bpp)2]·5H2O}n (1) (1,3-H2pda = 1,3-phenylene-diacrylic acid, bpp = 1,3-bis(4-pyridyl)-propane) was obtained from the hydrothermal reaction of Zn(NO3)2·6H2O, 1,3-H2pda, bpp in a 1:1:1 molar ratio in the presence of NaOH. Single-crystal X-ray diffraction analysis reveals that 1 is a two-fold interpenetrating two-dimensional network containing small cavities. Within each cavity of the entangled network, five water molecules are aggregated to form an unique discrete linear (H2O)5 water cluster. Thermal and luminescent properties of 1 were also investigated.

► A two-fold interpenetrating 2D 44-sql coordination network has been synthesized.
► The 2D coordination polymer encapsulates discrete linear (H2O)5 water clusters.
► The water clusters were stabilized by hydrogen bonds.
► The water clusters linked the entangled 2D nets into a 3D supramolecular framework.