The versatility of lithium cation coordination modes in salts with [W(CN)6(bpy)]2-anions

The synthesis and spectral and structural descriptions of two salts of formulas {[Li][Li(H2O)(mu-CN)(3)]}[W(CN)(3)(bpy)] (1) and {Li}{[Li(mu-CN)(2)][Li(mu-CN)(3)]mu-Cl}[W(CN)(bpy)]center dot 2H(2)O (2) were described. The structural investigation shows the influence of the size and charge of Li(+)on the nature of the CN-/Li(+)interaction and thus on the structure of the compounds. Both salts crystallize in the triclinicP1 & x304; space group with very similar cell parameters (a,bandcdiffer by no more than 0.05 angstrom,alpha,beta and gamma less than 1 degrees, and cell volume less than 4 angstrom(3)) in spite of the different complex formulas. In1, two different lithium cations are observed. Only one compensates the anion charge, while the second one is tetrahedral and forms a complicated 1D networkviathree nitrogen atoms of cyano ligandstransto a bpy molecule. The molecular wires connect neighbouring molecules only by weak intermolecular interactions. In2, the 2D structure, with layers connected only by pi-pi stacking interactions, is observed. Lithium cations are involved in bonds with the nitrogen of cyano ligands.