Syntheses, Structures, and Magnetic Properties of Five Novel Octacyanometallate-Based Lanthanide Complexes with Helical Chains

The reactions of octacyanometallates [M(CN)8]3‑ (M = Mo, W) and lanthanide ions Ln3+ (Ln = Pr, Sm, Eu) through the solution diffusion method in the presence of chelated aromatic ligands 1,10-phenanthroline (phen) or 3,4,7,8-tetramethyl-1,10-phenanthroline (tmphen) have yielded five new [M(CN)8]3–-based bimetallic complexes with helical structures: [Ln(phen)2(H2O)Mo(CN)8]2[(n-C4H9)4N](NO3)·2CH3CN·4H2O [Ln = Sm(1), Eu(2)], [Sm(tmphen)2(DMF)2][W(CN)8]·2H2O (3), and [Pr(tmphen)(DMF)5][M(CN)8]·DMF·2H2O [M = Mo(4), W(5)]. The Ln3+ centers are linked alternately by [M(CN)8]3– units through two trans V-shaped cyano groups to form the left- and right-handed helical chains running along the screw axis. Magnetic measurements revealed the presence of an antiferromagnetic interaction between metal centers in 4 and 5.