A Ferromagnetically Coupled, Bell-Shaped [Ni₄Gd₅] Cage

Abstract

Reaction between NiCl2•6H2O, 2-hydroxy-4-methyl-6-phenyl-pyridine-3-amidoxime (H2L), benzoic acid and M(NO3)3•6H2O (M = Gd, Y) in MeCN under basic conditions, yields the complexes [Ni II 4Gd III 5(PhCOO)10(HL)4(HLzw)4(OH)2(NO3)2]Cl•13.6MeCN•H2O (1•13.6MeCN 2 •H2O) and [Ni II 4Y III 5(PhCOO)10(HL)4(HLzw)4(OH)2(NO3)1.5(H2O)0.5]0.5Cl(NO3)•3H2O (2•3H2O). Both clusters display similar structures, consisting of a bell-shaped {Ni II 4M III 5} unit, in which a linear 'zig-zag' {Ni4} subunit bisects the central {M III 5} 'ring'. Direct (dc) and alternating current (ac) magnetic susceptibility measurements carried out in the 2-300 K temperature range for complexes 1 and 2 revealed ferromagnetic intermolecular interactions, while heat-capacity measurements for the Gd analogue suggest that complex 1 lowers its temperature from T = 9.6 K down to 2.3 K by adiabatically demagnetizing from Bi = 7 T to Bf = 0.

Selective Coordination of Self-Assembled Hexanuclear [Ni4Ln2] and [Ni2Mn2Ln2] (Ln = DyIII, TbIII, and HoIII) Complexes: Stepwise Synthesis, Structures, and Magnetic Properties

“…50 K. Below this temperature, χ M T ( T ) for [Dy 2 Ni 4 ] increases, reaching a maximum of 65.6 cm 3 K mol –1 at 3.5 K before decreasing to 59.10 cm 3 K mol –1 at 2 K. A similar behavior is observed for [Tb 2 Ni 4 ] and [Ho 2 Ni 4 ] ; i.e., χ M T ( T ) for complex 2 increases to 58.9 cm 3 K mol –1 at 4 K before decreasing to 51.9 cm 3 K mol –1 at 2 K, while for complex 3 , it increases to 59.26 cm 3 K mol –1 at 3 K before decreasing to 55.4 cm 3 K mol –1 at 2 K. Conversely, the χ M T ( T ) data for complexes 4 and 5 gradually decrease from room temperature to approximately 10 K. Below this temperature, χ M T ( T ) increases, reaching a maximum of 36.1 cm 3 K mol –1 at 2 K for complex 4 and 29.84 cm 3 K mol –1 at 3 K before decreasing to 28.96 cm 3 K mol –1 at 2 K for complex 5 . χ M T ( T ) for 6 decreases gradually upon cooling, reaching a value of 23.62 cm 3 K mol –1 at 2 K. The upsurge of χ M T at low temperatures suggests the existence of inter/intraferromagnetic interactions operating in the systems. − It is interesting to note that the upsurge is less pronounced for the [Ni 2 Mn 2 Ln 2 ] sets of molecules than for the [Ni 4 Ln 2 ] molecules.…”

Structural and Magnetic Properties of a {GdCu5}2Metallacrown Dimer with a Disulfonate Linker

“…[15][16][17][18][19][20] Interest in Gd(III)-containing complexes arises mainly from their potential application in magnetic refrigeration. [21][22][23] Recent reports devoted to the studies of quantum qubits built from various lanthanide complexes [24][25][26][27][28] have generated additional interest in studies of Ln(III)-containing assemblies. Weakly coupled discrete supramolecular assemblies from mono- [29] and polynuclear complexes [30] can provide interesting systems for investigating quantum information processing (QIP).…”

Ferromagnetically coupled CoII2LnIII2 complexes (where LnIII = Ho, Er, Yb): experimental and theoretical investigations

“…[25][26][27] In general the 4f and 3d-4f metal clusters consisting of isotropic metal ions such as Gd III (S = 7/2, 8 S 7/2 ), Mn II , Fe III , Co II , Ni II , and Cu II are widely used to investigate MCE behavior. 12,13,[28][29][30][31][32][33][34][35][36][37][38] Although the high spin and small or negligible magnetic anisotropy are the pre-requisite to achieve magnetothermal properties, a recent report on [{Dy(OAc) 3 (H 2 -O) 2 } 2 ]•4H 2 O (ref. 39) shows that anisotropic metal complexes can also be proposed for MCE properties.…”