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A series of three isostructural tetranuclear complexes with the general molecular formula [Ln(μ-OH)(L)(μ-piv)(MeOH)] (Ln = Gd 1, Dy 2 and Ho 3; LH = [1,3-bis(o-methoxyphenyl)-propane-1,3-dione]) were isolated and unambiguously characterized by single crystal XRD. Under similar reaction conditions, simply changing the co-ligand from pivalate to 2,6-bis(hydroxymethyl)-p-cresol (LH') led to the isolation of dinuclear Ln(iii) complexes with the general molecular formula [Ln(L)(μ-LH')]·4DMF (Ln = Gd 4, Dy 5 and Ho 6). Direct current magnetic susceptibility data studies on the polycrystalline sample of 1-6 and the results reveal the existence of weak antiferromagnetic exchange interactions between the lanthanide ions in 1 which is evident from the spin Hamiltonian (SH) parameters (J = -0.055 cm and g = 2.01) extracted by fitting χT(T). On the other hand, though complex 4 exhibits weak antiferromagnetic coupling (J = -0.048 cm and g = 1.99) between the Gd(iii) ions, the χT(T) data of complexes 5 and 6 unambiguously disclose the presence of ferromagnetic interactions between Dy(iii) and Tb(iii) ions at lower temperature. Magnetization relaxation dynamics studies performed on 2 show frequency dependent out-of-phase susceptibility signals in the presence of an optimum external magnetic field of 0.5 kOe. In contrast, complex 5 shows slow magnetization relaxation with an effective energy barrier (U) of 38.17 cm with a pre-exponential factor (τ) of 1.85 × 10 s. The magnetocaloric effect (MCE) of complexes 1 and 4 was extracted from the detailed magnetization measurement and the change in the magnetic entropy (-ΔS) of 1 and 4 was found to be 25.57 J kg K and 12.93 J kg K, respectively, at 3.0 K for ΔH = 70 kOe.

A robust and an unusual three coordinate Co(II) complex [Li(DME)3] [Co(L)3] (1, where L = Lithium (2,6-diisopropylphenyl) amide and DME = Dimethoxyethane) shows an easy plane magnetic anisotropy (D) which...

A series of rare six-coordinate dinuclear Ln(III) complexes [Ln2(µ-Cl)2Cl4Li2(L)2(THF)6] were structurally characterized using a bulky amide ligand (L; Ln = Gd(1); Dy(2) and Y(3)). Detailed magnetic studies disclose that a...

Ferrocenyl betadiketones were reacted with hydrated lanthanide trihalides in presence of a base to yield red color solids, whose structures were characterized by single crystal X-ray diffraction technique. Structural analysis revealed the formation of nona-and tetranuclear lanthanide oxo-hydroxo clusters [Dy9(l4-O)2(l3-OH)8(l-Fca)8(Fca)8] ) [HN(C2H5)3] + (1), [Ln4(l-OH)2(l-OCH3)4(CH3OH)2(Fctfa)6] Ln = Yb (2), Lu (3), and [Ln4(l-OH)2(l-OCH3)4( CH3OH)2(Fcpfa)6] Ln = Yb (4), Lu (5). Magnetism studies revealed that 1 shows slow relaxation of magnetisation. Cyclic voltammetry studies of 1 reveal electrochemically stable quasi reversible oxidation systems whereas 2-5 showed irreversible nature..