Structural Conversion and Magnetic Studies of Low-Dimensional LnIII/MoV/IV(CN)8 (Ln = Gd–Lu) Systems: From Helical Chain to Trinuclear Cluster

The slow diffusion reaction of octacyanometallate [MoV(CN)8]3–, lanthanide ions (Gd–Lu), and 1,10-phenanthroline (phen) in CH3CN/H2O has yielded eight isostructural one-dimensional chains, [LnIII(phen)2(H2O)MoV(CN)8]2[(n-C4H9)4N](NO3)·2CH3CN·4H2O (Ln = Gd(1), Tb(2), Dy(3), Ho(4), Er(5), Tm(6), Yb(7), Lu(8)), in which [LnIII(phen)2(H2O)]3+ and [MoV(CN)8]3– units are linked alternatively through cyanide groups, generating left- and right-handed helices. Interestingly, 1–8 undergo a resolvation–recrystallization process upon prolonging the diffusion-reaction time, together with the valence change from V to IV of Mo center and structural dimensionalities switching from helical chains to trinuclear clusters, (Hphen)2.5[LnIII0.5(phen)(H2O)][MoIV(CN)8]·1.5CH3CN (Ln = Gd(9), Tb(10), Dy(11), Ho(12), Er(13), Tm(14), Yb(15), Lu(16)). Magnetic studies of 1–16 revealed the typical effects induced by single-ion magnetic anisotropy and/or the population of low-lying excited states, and 11 and 13 showed extraordinary fie...