Poly[diaqua(μ-4,4′-bipyridine-κ²N:N′)bis(μ-cyanido-κ²C:N)bis(cyanido-κC)nickel(II)copper(II)]: a metal–organic cyanide-bridged framework

Abstract

The structure of the title compound, [NiCu(CN)4(C10H8N2)(H2O)2]n or [{Cu(H2O)2}(mu-C10H8N2)(mu-CN)2{Ni(CN)2}]n, was shown to be a metal-organic cyanide-bridged framework, composed essentially of -Cu-4,4'-bpy-Cu-4,4'-bpy-Cu- chains (4,4'-bpy is 4,4'-bipyridine) linked by [Ni(CN)4](2-) anions. Both metal atoms sit on special positions; the Cu(II) atom occupies an inversion center, while the Ni(II) atom of the cyanometallate sits on a twofold axis. The 4,4'-bpy ligand is also situated about a center of symmetry, located at the center of the bridging C-C bond. The scientific impact of this structure lies in the unique manner in which the framework is built up. The arrangement of the -Cu-4,4'-bpy-Cu-4,4'-bpy-Cu- chains, which are mutually perpendicular and non-intersecting, creates large channels running parallel to the c axis. Within these channels, the [Ni(CN)4](2-) anions coordinate to successive Cu(II) atoms, forming zigzag -Cu-N[triple-bond]C-Ni-C[triple-bond]N-Cu- chains. In this manner, a three-dimensional framework structure is constructed. To the authors' knowledge, this arrangement has not been observed in any of the many copper(II)-4,4'-bipyridine framework complexes synthesized to date. The coordination environment of the Cu(II) atom is completed by two water molecules. The framework is further strengthened by O-H...N hydrogen bonds involving the water molecules and the symmetry-equivalent nonbridging cyanide N atoms.

Heterometallic cyanide-bridged complexes containing RhIRuIIRhI triad: NMR data on exchange reactions and ligand effect transmission

“…The key concepts concerning cyanide-bridged transition metal complexes and a variety of strategies to synthesize them were thoroughly discussed in the literature (see e.g. [2][3][4][5][6][7][8][9][10][11][12][13][14][15] and numerous refs. therein).…”

A New Family of Bimetallic Framework Materials Showing Reversible Structural Transformations

“…For example, using hexacyanochromate(III) it was possible to prepare bimetallic three-dimensional (3D) and chiral one-dimensional (1D) metal−organic cyano-bridged materials which exhibit ferromagnetism . In another case, we have successfully prepared a bimetallic 3D metal−organic cyano-bridged framework material using 4,4′-bipyridine, tetracyanonickelate and copper sulfate …”

“…42 In another case, we have successfully prepared a bimetallic 3D metal-organic cyano-bridged framework material using 4,4′-bipyridine, tetracyanonickelate and copper sulfate. 43 Our interests are in the construction of materials, porous or not, in which such phase transformations take place. 44 Here we report on three new 3D metal-organic cyano-bridged frameworks, prepared in a very simple manner from the ligand 1,3-diaminopropane (tn), the hexacyanometalates [Co(CN) 6 4 : M ) Cd 2+ , Cu 2+ ).…”