The Crystal Structure of a Hofmann-en Type Pyrrole Clathrate, catena-μ-Ethylenediaminecadmium(II) catena-Tetra-μ-cyanonickelate(II)-Pyrrole (1/2)

The crystal structure of the titled pyrrole clathrate Cd(NH2CH2CH2NH2)Ni(CN)4·2C4H5N has been determined from three-dimensional X-ray data collected by counter techniques. The clathrate crystallizes in the orthorhombic space group Pmmm with a=7.618(3), b=7.641(10), c=7.861(4)Å, Z=1, Dm=1.69g cm−3, and Dx=1.70 g cm−3. The structure has been refined by the full-matrix least-squares procedure to a conventional R index (on F) of 0.057 for 462 observed reflections. The metal complex host-framework has a three-dimensional infinite cage structure where the ambident ethylenediamine molecules span Cd atoms at the corners of unit cell along the [001] direction and the ambident cyanide ions make infinite two-dimensional networks parallel to (001) by spanning the Cd atoms with the Ni atom at (1/2, 1/2, 0). The two crystallographically independent pyrrole molecules are enclathrated in the molecular spaces of the cages in the host-framework. The statistical dispositions observed for en and pyrrol molecules can be interpreted in terms of motional behavior of these molecules in the crystal.