Metal−Organic Framework H-Bonded Like a Polycatenane:  Coexistence of Acyclic Water Trimer and Nonamer

Pyridine-2,6-dicarboxylic acid and 1,2-di-4-pyridylethylene react hydrothermally with nickel(II) nitrate, forming a metal−organic framework that forms a polycatenane-like structure through H-bonding interactions between water molecules and carboxylate O atoms with void spaces. Discrete acyclic trimeric and nonameric water clusters occupy the voids in the structures. X-ray powder diffraction and X-ray structure analysis have been used to characterize this compound. Crystal data for <b>1 </b>{(3dpeH₂)[Ni(pdc)₂]₃·15H₂O}:  monoclinic space group <i>P</i>2₁/<i>c</i>,<i> a</i> = 24.730(5) Å, <i>b</i> = 19.895(2) Å, <i>c</i> = 17.257(4) Å, β = 104.832(5)°, <i>V </i>= 8208(4) ų, <i>Z</i> = 4, R1 = 0.0429, wR2 = 0.1072, and <i>S</i> = 1.051.