Computational study of exchange coupling in homo- and heterometallic oxo- and carboxylato bridged trinuclear complexes with triangular {FeIII2M(μ3-O)} (M = FeIII, NiII, CoII) core

• Exchange interactions in carboxylates with FeIII2M(μ3-O) (M = FeIII, CoII, NiII) core are modeled.
• |JFeFe| and |JFeM| decrease with R in RCO2− in the row C(CH3)3 > CH3 > CCl3 ≈ CF3.
• Main exchange pathway in the complexes is μ3-oxo-bridge.

Using broken symmetry approach (DFT-BS, 6-311G(d)/B3LYP level of theory) the structure and magnetic exchange interactions in homo- and heterometallic oxo-centered trinuclear carboxylate complexes [Fe2M(μ3-O)(RCO2)6(H2O)3]n+ (M = FeIII, n = 1; NiII, CoII, n = 0; R = C(CH3)3, CH3, CCl3, CF3) were evaluated. The influence of metal ion and the nature of the carboxylate bridging ligand on the structure and magnetic properties of trinuclear complex is discussed. It was shown, that antiferromagnetic exchange interactions in both FeIII–FeIII and FeIII–MII (M = Ni, Co) pairs weakens in the row trimethylacetate > acetate > trichloroacetate ≈ trifluoroacetate.

Using broken symmetry approach (6-311G(d)/B3LYP level of theory) the structure and magnetic exchange interactions in homo- and heterometallic oxo-centered trinuclear carboxylate complexes [Fe2M(μ3-O)(RCO2)6(H2O)3]n+ (M = FeIII, n = 1; NiII, CoII, n = 0; R = C(CH3)3, CH3, CCl3, CF3) were evaluated.Figure optionsDownload as PowerPoint slide