Synthesis, structure and magnetic properties of one chiral heptanuclear Fe cluster: {Fe[(FeL)2(μ2-OH)]3(μ2-OH)6} · 13H2O

One chiral heptanuclear FeIII cluster, {Fe[(FeL)2(μ2-OH)]3(μ2-OH)6} · 13H2O (1) (H2L=N-(2-hydroxybenzyl)-l-histidine), has been synthesized and characterized structurally and magnetically. Complex 1 crystallizes in the chiral space group C2. The heptanuclear FeIII cluster of 1 has a propeller-like [Fe7(μ2-OH)9]12+ core, with the peripheral ligation provided by six tetradentate L2− ligands. The configurations of the C- and the N-centers of L2− is (S, R) and the central atom Fe4 is chiral Λ configuration. All FeIII centers are hexacoordinated, displaying a distorted octahedral coordination sphere. Variable temperature magnetic studies showed complex 1 is antiferromagnetic with C = 14.27 cm3 K mol−1 and θ = −27.56 K. Magnetisation and susceptibility measurements show that cluster 1 exhibits a ground spin state of S = 3.