Synthesis, crystal structures, and magnetic properties of cyano-bridged honeycomblike layers M^V-Cu^II (M = Mo, W) chelated by a macrocyclic ligand

Two cyano-bridged Cu^II-M^V [M = Mo (2), W (3)] complexes formed by self-assembly of octacyanometalates [M(CN)₈] ^3- (M = Mo, W) with a new molecular precursor [Cu(L2)]²⁺ (1) (L2 = a macrocyclic ligand) in a 2:3 ratio have been investigated in terms of structures and magnetic behaviors. The M₂Cu₃ repeating unit of both bimetallic compounds is extended to a two-dimensional honeycomblike layered structure. The pendant ethyl groups on L2 noticeably influence the structural parameters around the Cu center. Compared with the system composed of a macrocycle without a side group, Cu-N_ax (ax = axial) distances become shorter and the Cu-N_ax-C_ax angles are more bent for 2 and 3. The magnetic data denote that the Cu(II) and M(V) spins undergo explicit ferromagnetic interactions via CN bridges. From a structural and magnetic point of view, given that the Cu-N_ax bond length in the tetragonally distorted octahedral Cu(II) environment is long enough, the overall ferromagnetic character remains despite the variation of Cu-N _ax-C_ax angle in this system.