Rational design of metal-organic frameworks based on 5-(4-pyridyl)tetrazolate: From 2D grids to 3D porous networks

The hydrothermal reactions of Zn(ClO4)(2).6H(2)O/ Cu(NO3)(2).6H(2)O with 5-(4-pyridyl)tetrazole in an ethanol/ water or ethanol/water/pyridine medium yield one 2D and one 3D metal-organic coordination framework [Zn-2(OH)(4-Ptz)(3)] (1) and [Cu(4.ptz).0.5(py)] (3) [4-ptz = 5-(4-pyridyl)tetrazolate, py = pyridine], respectively. Complex 1 possesses two identical and independent rectangular grid sheets with twofold parallel interpenetration, in which the four-connected nodes of the net are provided by Zn-2(OH) units connected to one another through 4-ptz and (4-PtZ)(2) bridges. These composite sheets are stacked one on top of another by hydrogen-bonding interactions to afford a 3D structure. There are many structural similarities between complex 1 and the recently reported 2D layered network [Zn(OH)(4-ptz)(H2O)] (2), in particular the components of the network, the coordination mode of the 4-ptz ligand and the in situ formation of hydroxy groups. Complex 2 can be synthesized by the hydrothermal reaction of Zn(ClO4)(2).6H(2)O and 5-(4-pyridyl)tetrazole in an ethanol/water/pyridine medium. The structural characterization of complex 3 shows a porous structure that contains the guest pyridine molecules. Additionally, compounds 1 and 2 exhibit strong fluorescence at room temperature in the solid state. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).