Enforcing Ising-like magnetic anisotropy via trigonal distortion in the design of a W(v)-Co(ii) cyanide single-chain magnet.

A new octacyanotungstate(V) based single chain magnet {[(Tpm) Co(DMF) W(CN)(8)](2)[ Co(DMF)(4)]. 2DMF}(n) (1, Tpm 1/4 1,1, Tpm =1,1,1-trispyrazoylmethane), with an effective barrier of 39.7(3) cm(-1) is reported. The Ising- like magnetic anisotropy of the chain originates from the nearly parallel local orientations of the Co(II) ions with the source of the uniaxial magnetic anisotropy being a trigonal distortion of the octahedral environment with the fac-tridentate capping Tpm ligand.