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RESEARCH PRODUCT

Structures and Magnetic Properties of Bis(μ‐phenoxido), Bis(μ‐phenoxido)‐μ‐carboxylato and Bis(μ‐phenoxido)bis(μ‐carboxylato) Fe III Ni II Compounds – Magnetostructural Correlations

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This report describes the syntheses, characterization, crystal structures and magnetic properties of five dinuclear FeIIINiII compounds derived from two Robson-type tetraiminodiphenol macrocyclic ligands H2L1 and H2L2, which are the [2+2] condensation products of 4-ethyl-2,6-diformylphenol and 1,3-diaminopropane (for H2L1) or 2,2-dimethyl-1,3-diaminopropane (for H2L2). The compositions of the compounds are [FeIII(N3)2L1NiII(H2O)2](ClO4) (1), [FeIII(benzoato)L1NiII(H2O)(μ1,3-benzoato)](ClO4) (2), [FeIII(benzoato)L2NiII(H2O)(μ1,3-benzoato)](ClO4) (3), [FeIIIL2NiII(μ1,3-acetato)2](ClO4)·H2O (4) and [FeIIIL2NiII(μ1,3-propionato)2](ClO4)·H2O (5). The bridging moieties between the two metal ions and the azido and carboxylato moieties in these compounds are of the following types: (1) In 1, the bridging moiety is a bis(μ-phenoxido) ligand, and two azido ligands are monodentate to the FeIII centre; (2) In 2 and 3, the bridging moiety is a bis(μ-phenoxido)-μ1,3-benzoato ligand, and the second benzoato ligand is monodentate to the FeIII centre; (3) In 4 and 5, the bridging moiety is a bis(μ-phenoxido)bis(μ1,3-acetato/propionato) ligand. Variable-temperature and variable-field magnetic data reveal ferromagnetic interactions in 2–5 and an antiferromagnetic interaction in 1 with J values of –9.22 cm–1 for 1, 0.50 cm–1 for 2, 5.65 cm–1 for 3, 13.00 cm–1 for 4 and 14.57 cm–1 for 5. An excellent magnetostructural correlation and interesting structural aspects regarding the bond lengths to the FeIII or NiII centres in some structures have been obtained.