A linear {Fe2Ni} cluster and a structurally closely related quasi one-dimensional {Fe2Ni} chain

The solvothermal reaction between FeCl3·6H2O, NiCl2·6H2O, 2-hydroxynaphthaldehyde, and glycine in MeOH results in the formation of the trinuclear heterometallic cluster [FeΙΙΙ2NiΙΙ(L1)4(MeOH)4] (1) in good yield, while the same reaction upon replacing glycine with dimethyl-glycine, results in the formation of the closely related quasi one-dimensional coordination polymer {[FeΙΙΙ2NiΙΙ(L2)4(MeOH)2]n} (2) (L1, L2: the dianionic form of the Schiff-base ligand derived from the condensation of 2-hydroxynaphthaldehyde and glycine (L1 for 1), or dimethyl-glycine (L2 for 2)). The structure of 1 describes a linear trimetallic {FeIII2Ni} unit, whereas complex 2 consists of repeating linear {FeIII2Ni} units with each one connected to two neighbouring units via four coordination bonds, forming a quasi one-dimensional chain. The structural similarity between complex 1 and the repeating unit of complex 2 is remarkable. However, their magnetic properties differ significantly, with complex 1 displaying dominant ferromagnetic interactions, and complex 2 showing antiferromagnetic interactions.