Synthesis, structure and magnetic properties of a 2D cyano-bridged mixed-valence CuIICu2I assembly containing ladder-like chain

A cyano-bridged mixed-valence CuIICu2I assembly, {CuII(NH3)3CuI(CN)[CuI(CN)3]}n (1), was directly synthesized in diluted ammonia aqueous solution by Cu(NO3)2·3H2O reacting with KCN. The X-ray crystallography displays that complex 1 is crystallized in Monoclinic, P2(1)/n space group with a=9.4680(19), b=12.626(3), c=9.4960(19) Å and β=99.83(3)°. The single crystal structure of complex 1 exhibits 2D network formed by cyanide bridges connecting the ladder chains containing CuII–NC–CuI–NC–CuI–CN–CuII linkage. The magnetic investigation reveals the weak antiferromagnetic interactions between CuII ions in the ladder chain with g=2.138, J∥=−3.39 cm−1 (along the chain) and J⊥=−2.92 cm−1 (perpendicular to the chain) although eight diamagnetic atoms bridging between magnetic center ions. It is suggested due to the largest ionic radius of CuI ion in the first row transition metal ions leading to the diffusion of 3d orbitals of CuI ion, furthermore, the ability of [CuI(CN)3] mediating magnetic interaction is strengthened.