Nanoporous three-dimensional networks topologically related to Cooperite from the self-assembly of copper(I) centres and the "square-planar" building block 1,2,4,5-tetracyanobenzene

The deliberate assembly of a Cu-I 3D coordination network with the Cooperite (PtS) topology, namely [Cu(mu(4)-TCNB)][PF6] 1, has been accomplished by using the pseudo-square-planar building block 1,2,4,5-tetracyanobenzene (TCNB). It has been obtained by reacting [Cu(NCMe)(4)][PF6] with TCNB (in molar ratio 1 : 1) in solvent mixtures of CH2Cl2 and of a poorly basic solvent, like ethanol, isopropanol, benzyl alcohol or acetone. The crystals are orthorhombic, space group Cccm, with a = 8.157(1), b = 18.634(2), c = 11.613(1) Angstrom, Z = 4. The framework is based on tetrahedral Cu-I centres and tetradentate mu(4)-TCNB ligands and presents cavities containing guest solvent molecules. On performing the same reaction in CH2Cl2-THF a 3D three-connected polymeric species, [Cu(mu(3)-TCNB)(THF)][PF6] 2, is obtained. Compound 2 gives monoclinic crystals, space group P2(1)/c, with a = 21.617(2), b = 11.127(3), c = 16.294(2) Angstrom, beta = 111.61(2)degrees, Z = 8. In 2 the TCNB ligands are tridentate and the copper centres achieve a tetrahedral coordination on forming a bond with a THF molecule. The network presents an unprecedented topology, (8(2)10)-b, and the crystals undergo, by thermal activation, an unusual crystal-to-crystal transformation, losing the THF molecules to give the same frame as 1.