Synthesis and full characterisation of the first discrete binuclear complex featuring a two-electron (sigma) mu(2)-kappa C :kappa C bridging cyanide

Small ring macrocycles incorporating nitrile-functionalised arms can suppor t binuclear Ag-I complexes bearing bridging CN- ligands. The X-ray crystal structure, IR and CP MAS C-13 NMR spectra are reported for [Ag-2(L-1)(2)(mu -CN)][BF4]. MeCN (1), which represents the first complex incorporating a di screte mu(2)-kappa C:kappa C symmetrically bridged two-electron-donating CN - ligand. The complexes [Ag-2(L-2)(2)(mu-CN)][BF4] (3), and [Ag-2(L-3)(2)(m u-CN)][BF4] (4), have also been synthesised, and have been characterised bo th structurally and spectroscopically. In contrast to 1, 3 and 4 feature li near bridging mu(2)-kappa C:kappa N, four-electron-donating CN- ligands. Th erefore, the length of the aliphatic chain in the functionalised macrocycle s plays a crucial role in determining the observed co-ordination mode of th e bridging CN- ligand.