Three unprecedented open frameworks based on a pyridyl-carboxylate: synthesis, structures and properties

Three open frameworks, [Ni(pnta)(2)]center dot 1.3DMF (1), [Zn-2(pnta)(3)(OH)]center dot 2DMF (2), and [Cd(pnta)(2)]center dot 3.8DMF (3), were obtained by solvothermal reactions between 6-(pyridin-4-yl)nicotinic acid (Hpnta) and nickel(II), zinc(II) and cadmium(II) nitrate, respectively. Compound 1 is a chiral framework with a fourfold interpenetrated diamondoid network structure and two types of chiral channels. Compound 2 also possesses the fourfold interpenetrated adamantanoid architecture with helical rhombic nanotube-like channels, each of which has two sides of double-layer walls and two other sides of single-layer walls. Compound 3 is a rarely reported double-walled framework with bcu topology. The luminescent properties of compounds 2 and 3 have been studied in the solid state at room temperature.