Structures and magnetic properties of imidazolate-bridged tetranuclear and polymeric copper(II) complexes

Structural and Magnetic Diversity Based on Different Imidazolate Linkers in Cu(II)-Azido Coordination Compounds

“…The values of the fitted parameters agree well with the structural topology of 2 . The coupling through μ 1,1 -N 3 bridging is ferromagnetic as expected, whereas the 2-methylimidazole bridging ligand creates a strong antiferromagnetic coupling ( J AF = −88(2) cm –1 ), which agrees well with the literature reports. ,, …”

“…The best-fit results are the following parameters: J 1 (imidazolate bridge) = −28.4(2) cm –1 ; J 2 [(μ 1,1 -N 3 ) 2 bridge] = 16.2(1) cm –1 ; g = 2.11(1), z ′ J ′ = 1.65(2) cm –1 , TIP = 366 × 10 –6 cm –1 mol –1 (TIP, temperature independent paramagnetism), and R = 2.38 × 10 –5 (Figure ). The J values agree with those reported in the literature for similar bridging ligands. ,, It should be noted that the best fitting gives a small positive z ′ J ′ parameter and thus indicates a ferromagnetic intermolecular interaction. This feature is likely due to the fact that these intermolecular interactions are made between magnetic orbitals with the unpaired electron in the z 2 and x 2 – y 2 atomic orbitals, respectively (orthogonal to each other).…”

“…The value of the J 1 (antiferromagnetic) must be attributed to the imidazole bridges, which is well reported in the literature. ,, The ferromagnetic interaction ( J 2 ) originates from two azido ligands in end-on (EO) conformation. According to the reported experimental and theoretical data, this kind of geometry with the corresponding Cu–N EO –Cu angles would give ferromagnetic coupling, as it occurs in compound 3 .…”

Unprecedented Ferromagnetic Exchange Coupling of a Square-Planar Cu4O unit in a scu-Type Porous Metal–Organic Framework and Its Reticular Chemistry

“…Since the Cu···Cu distance bridged by dmtrz in imidazole mode is over 6.0 Å, which mediates a poor superexchange interaction, the ferromagnetic behavior of MAC-15 should be increased from the unique Cu 4 O SBU. In this sense, the magnetic susceptibility could be tentatively analyzed on the basis of the square model by applying the Kambe vector-coupling method and Van Vleck equation, meanwhile considering the presence of two isolated Cu­(II) ions . The best fit by MagProp in DAVE 2.5 software gives the parameters J = 6.74 cm –1 and g = 2.16 with R 2 = 0.99974 (Figure S10), confirming the dominant ferromagnetism of MAC-15.…”

“…In this sense, the magnetic susceptibility could be tentatively analyzed on the basis of the square model by applying the Kambe vector-coupling method and Van Vleck equation, meanwhile considering the presence of two isolated Cu(II) ions. 28 The best fit by MagProp in DAVE 2.5 software 29 gives the parameters J = 6.74 cm −1 and g = 2.16 with R 2 = 0.99974 (Figure S10), confirming the dominant ferromagnetism of MAC-15.…”