Structure and magnetic properties of two cyanide - bridged one - dimensional M – CuII ( M FeIII or FeII ) bimetallic assemblies from ferricyanide and CuN

Two bimetallic assemblies K[Cu(cyclam)][Fe(CN)6] 4H2O 1 and [Cu(L)][Cu(L )][Fe(CN)6] 6.5H2O 2 (cyclam = 1,4,8,11-tetraazacyclotetradecane; L = N,N -bis(2-pyridylmethylene)-1,3-propanediamine and L = N-2-pyridylmethylene-1,3-propanediamine) have been prepared from the reaction of [Fe(CN)6] 3 and the precursors [Cu(cyclam)] and [Cu(L)] , respectively, and their structure and magnetic properties studied. The structure of 1 consists of polymeric zigzag chains of alternating [Fe(CN)6] 3 and [Cu(cyclam)] units, K cations and crystal water molecules. In the crystals the chains are linked by CN–K–NC interactions, to form a two-dimensional layer structure. Magnetic measurements show a weak ferromagnetic intrachain interaction based on the strict orthogonality of the magnetic orbitals of the Fe and Cu. In the structure of 2 each [Cu(L)] unit is bonded to centrosymmetric [Fe(CN)6] 4 and [Cu(L)Fe(CN)6Cu(L)] units through two cis bridging cyanide ligands. Owing to the symmetry, a unique one-dimensional zigzag chain structure is formed through trans bridging cyanide ligands of the two crystallographically non-equivalent [Fe(CN)6] 4 groups. In the course of the reaction the [Fe(CN)6] 3 ion undergoes a reduction to [Fe(CN)6] 4 whereas the [Cu(L)] ion partly hydrolyses to [Cu(L)] . Compound 2 is essentially paramagnetic within the chain.