Browsing by Author "Ishida T"

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    Anion Effects on the Structural and Magnetic Properties of a Series of Trinuclear CuII –LnIII –CuII Complexes
    (American Chemical Society, 2025-11-04) Matheson BE; Dais TN; Donaldson ME; Takeshi S-I; Lyu L; Takano R; Ishida T; Rowlands GJ; Plieger PG
    Two series of heterometallic CuII2LnIII complexes, ([Cu2Ln(H4L)2(MeOH)2Br](MeOH)4(Et2O)(Br2), where Ln = Y (1), Gd (2), Er (3), Tb (4)), and ([Cu2Ln(H4L)2(MeOH)2Cl2](MeOH)4(Et2O)Cl, where Ln = Y (5), Gd (6), Er (7), Tb (8), and H6L = (N,N′-bis(2,3,4-trihydroxybenzylidene)-1,2-phenylenediamine), were designed, synthesized, and characterized through X-ray and magnetic analyses. X-ray analysis revealed that the bromide containing complexes 1–4 possessed identical supramolecular arrangements, crystallizing in layers of 2D sheets, while chloride containing complexes 5–8 formed a 3D supramolecular lattice possessing an additional π–π stacking interaction per complex. DC magnetic susceptibility measurements showed that complexes 3 and 7 exhibited antiferromagnetic coupling between copper and erbium centers while the gadolinium (2 and 6) and terbium (4 and 8) containing complexes displayed ferromagnetic Cu─Ln coupling upon cooling. AC magnetic susceptibility measurements revealed that complexes 4 and 8 also displayed zero-field SMM behavior with Ueff = 17.8 and 16.0 K, respectively. The larger bromide anion in complex 4 aids in the isolation of the magnetic centers, resulting in a Ueff value higher than that of the chloride analogue.
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    Lanthanide induced variability in localised CoII geometries of four triangular L3Co3 IILnIII complexes
    (The Royal Society of Chemistry, 2022-02-03) Dais TN; Takano R; Ishida T; Plieger PG
    Four tetranuclear heterobimetallic triangle complexes [L3Co3Dy(NO3)2(H2O)(MeOH)5](NO3) (C1), [L3Co3Gd(NO3)3(MeOH)4] (C2), [L3Co3La(NO3)2(H2O)6](NO3)(H2O) (C3), and [L3Co3TbCl(NO3)2(H2O)0.5(MeOH)3.5] (C4), where H2L = 1,4-bisformylnaphthalene-2,3-diol, have been synthesised and structurally characterised. Each complex crystallises with a complete molecule in the asymmetric unit (Z' = 1) and displays near perfect octahedrality in two out of three CoII centres. The third CoII ion assumes a different coordination geometry in each complex: six-coordinate octahedral in C1, six-coordinate with a distortion towards trigonal prismatic in C2, five-coordinate trigonal bipyramidal in C3, and five-coordinate square pyramidal in C4; which has been attributed to increasing lanthanide cation size, coupled with a non-macrocyclic coordination environment. Continuous Shape Measurement (CShM) calculations and octahedral distortion parameter calculations were performed, using the SHAPE and OctaDist software packages, respectively, in order to aid in the assessment of each metal centre's local coordination geometry. The preliminary magnetic investigation of C3 found χ m T = 9.4 cm3 K mol-1 at 300 K and M = 7.1 μ B at 1.8 K, which are approximately two thirds the maximum theoretical values for three CoII ions and indicates the presence of a relatively large zero-field splitting parameter (D/k B = 65 K) operative in each CoII ion rather than exchange coupling between the CoII centres.