{[Cd(bpo)(SCN)₂]·CH₃CN}<i>_n</i>:  A Novel Three-Dimensional (3D) Noninterpenetrated Channel-Like Open Framework with Porous Properties

Abstract

Reaction of CdCl 2 ·0.5H 2 O with 2,5-bis(4-pyridyl)-1,3,4-oxodiazole (bpo) and NH 4 SCN in a 1:1:2 molar ratio under CH 3 CN−H 2 O medium afforded a novel neutral three-dimensional (3D) coordination polymer {[Cd(bpo)(SCN) 2 ]·CH 3 CN} n ( 1 ) [monoclinic, space group P 2 1 / c, a = 7.680(2) Å, b = 10.029(3) Å, c = 25.786(7) Å, β = 93.779(5)°, Z = 4]. The crystal structure reveals that 1 has a 3D noninterpenetrating open framework with guest CH 3 CN molecules in the cavities, in which the Cd II centers (with CdN 4 S 2 octahedral geometry) are bridged by the bpo molecules and SCN - groups. It is interesting that the two-dimensional sheet in this 3D network consists of 16-membered [Cd 4 ( μ -SCN- N, S ) 4 ] rings, and the bpo molecules extend these layers to a 3D structure, which is further stabilized by C−H···N hydrogen-bonding and strong π − π -stacking interactions. Thermogravimetric analysis and X-ray powder diffraction technique measurements illustrate that the framework of 1 is retained upon removal of the uncoordinated guest acetonitrile molecules, indicating that 1 might be used to generate microporous material.