Structure and magnetism of heptanuclear complex constructed by the encapsulation of octacyanotungstate(IV) with copper(II) cations of tripodal ligands

A new heptanuclear compound [{Cu(TPA)CN}6W(CN)2][ClO4]8·14H2O (1) (TPA = tris(2-pyridylmethyl)amine) was synthesized by the reaction of [Cu(TPA)]2 + unit and K4W(CN)8. The cyanometalate core is encapsulated by mononuclear copper moieties via cyano bridges. 1 crystallizes in monoclinic space group P21/c with a = 22.01(2) Å, b = 26.87(3) Å, c = 31.64(2) Å, β = 128.87(2)°, and Z = 4. Variable temperature magnetic measurements have demonstrated that very weak ferromagnetic interaction between the nearest paramagnetic CuII centers is exhibited. Thus weak ferromagnetic coupling might be transferred by single bondNCsingle bondWsingle bondCNsingle bond bridging units.