Synthesis, Structural Features and Physical Properties of a Family of Triply Bridged Dinuclear 3d-4f Complexes

Abstract

New dinuclear MII-LnIII complexes of general formulas [Cu(µ-L)(µ-OAc)Ln(NO3)2]·CH3CN·H2O (LnIII = Gd (1), Tb (2), Dy (3) and Er (4)), [Ni(CH3CN)(µ-L)(µ-OAc)Ln(NO3)2]·CH3CN (LnIII = Nd (5), Gd (6), Tb (7), Dy (8), Er (9) and Y (10)) and [Co(CH3CN)(µ-L)(µ-OAc)Ln(NO3)2]·CH3CN (LnIII = Gd (11), Tb (12), Dy (13), Er (14) and Y (15)) were prepared from the compartmental ligand N,N′-dimethyl-N,N′-bis(2-hydroxy-3-formyl-5-bromo-benzyl)ethylenediamine (H2L). In all these complexes, the transition metal ions occupy the internal N2O2 coordination site of the ligand, whereas the LnIII ions lie in the O4 external site. Both metallic ions are connected by an acetate bridge, giving rise to triple mixed diphenoxido/acetate bridged MIILnIII compounds. Direct current (dc) magnetic measurements allow the study of the magnetic exchange interactions between the 3d and 4f metal ions, which is supported by density functional theory (DFT) theoretical calculations for the GdIII-based counterparts. Due to the weak ferromagnetic exchange coupling constants obtained both experimentally and theoretically, the magneto-thermal properties of the less anisotropic systems (compounds 1 and 6) are also studied. Alternating current (ac)magnetic measurements reveal the occurrence of slight frequency dependency of the out-of-phase signal for complexes 8, 9 and 13, while complex 15 displays well-defined maximums below ~6 K.

3d Ion-Driven Hexanuclear Heterometallic Clusters with Amazing Structures and Magnetic Properties

“…The magnetic data were fitted according to the spin Hamiltonian Ĥ = −2 J 1 ( Ŝ Gd1 Ŝ Co2A + Ŝ Gd1A Ŝ Co2 ) – 2 J 2 ( Ŝ Gd1 Ŝ Co2 + Ŝ Gd1A Ŝ Co2A ) – 2 J 3 Ŝ Co2 Ŝ Co2A – 2 J 4 Ŝ Gd1 Ŝ Gd1A + D Co S z 2 + μ B H ( g Gd ( Ŝ Gd1 + Ŝ Gd1A )+ g Co ( Ŝ Co2 + Ŝ Co2A )) and using the PHI program, yielding g Co = 2.40, g Gd = 1.90, J 1 = 0.24 cm –1 , J 2 = 0.27 cm –1 , J 3 = −0.10 cm –1 , J 4 = −0.012 cm –1 , and D Co = |17.28| cm –1 ( R 2 = 99.99). The J CoGd values are comparable to the values observed for other doubly/triply bridged Co II Gd III complexes. − The closer the hinge angle is to 180°, the bigger the J CoGd value is. As expected, both Co–Co and Gd–Gd interactions are weak antiferromagnetic .…”

INVESTIGATION OF COORDINATION COMPOUNDS OF GADOLINIUM (III) WITH beta-DIKETONES

“…This is due to a wide range of practical applications of oxide and coordination compounds, composite, hybrid and polymeric materials based on lanthanides [1][2][3][4]. They find application in various fields of science and technology: as emission and magnetic materials in molecular spintronics as single-molecule magnets for storing ultrahighdensity information and quantum computing (quantum information processing) [5][6][7][8][9][10] for highly anisotopic systems based on Tb and Dy [11] , as low-temperature molecular magnetic coolers, which are evaluated by the magneto-caloric effect (MCE) [12], in magnetic resonance imaging (MRI) -contrast agents that, when introduced into the body, are localized in the internal organs, increasing the contrast between normal and affected tisue [12][13][14][15][16].…”

Investigation of Coordination Compounds of Gadolinium (III) With b-Diketones

“…This is due to a wide range of practical applications of oxide and coordination compounds, composite, hybrid and polymeric materials based on lanthanides. [1][2][3][4] They find application in various fields of science and technology: as emission and magnetic materials in molecular spintronics as single-molecule magnets for storing ultrahigh-density information and quantum computing (quantum information processing) [5][6][7][8][9][10] for highly anisotopic systems based on Tb and Dy, 11 as low-temperature mo-lecular magnetic coolers, which are evaluated by the magneto-caloric effect (MCE) [12], in magnetic resonance imaging (MRI) -contrast agents that, when introduced into the body, are localized in the internal organs, increasing the contrast between normal and affected tissue. [12][13][14][15][16] First of all, these are complex compounds of gadolinium and dysprosium, which is due to their paramagnetic properties.…”