Nested [Na6(H2O)]6+ encapsulation of nickel(II) coordination framework assembled from pyridyl-2,6-dicarboxylic acid

Hydrothermal reactions of pyridyl-2,6-dicarboxylic acid (H2PDC) and NiCl2 · 6H2O in the presence of NaOH and KOH, respectively afforded the products, {[Ni(PDC)(Cl)](Na)(H2O)/3}n (1) and K2[Ni(PDC)2] · 7H2O (2), of which 1 was characterized consisting of 3-D porous framework and [Na6(H2O)]6+ inclusions, and 2 was a mononuclear complex with potassium hydrate as counterion.