Synthesis, Crystal Structures, Magnetic Properties, and Fluorescence of Two Heptanuclear Co^III₄Ln^III₃ Compounds (Ln = Gd^III, Dy^III): Multiple Relaxation Dynamics in the Dy^III Analogue

Abstract

This report describes the synthesis, crystal structures, 3 ·3CH 3 OH·1.5H 2 O (2), where H 2 L is [1+1] condensation product of 3-methoxysalicylaldehyde and 2-amino-2-methyl-1-propanol. The heptametallic cores in 1 and 2 may be taken as consisted of two symmetry related trinuclear Co III Ln III Co III moieties and a central lanthanide center in such a way that each of the three metal ions of each of the two trinuclear moieties are bridged with the central lanthanide through bridging oxo/alkoxo/acetate ligands. DC [a]

Two-Dimensional Metal Azides Constructed by a Ln@Co6Cluster and Disordered Co3(N3)11Units

“…Usually, the EO azide conducts ferromagnetic interactions between Co II ions while the EE azide conducts antiferromagnetic coupling; thus, between the Co1 and the Co2 or the Co2 and the Co2/Co2′ the ferromagnetic interactions are dominant. The χ m T products of 2 are different from that of 1 , which decreases slowly on cooling with a minimum at about 44 K and then increases rapidly to a maximum at about 3.6 K. The magnetic data of 2 in the specific range are fitted according to the Curie–Weiss law (Figure c), which gives C = 42.07 cm 3 K mol –1 and θ = −0.10 K. The Curie constant is consistent with the value of one Dy III ion ( 6 H 15/2 and g = 4/3 14.17 cm 3 K mol –1 ) and nine Co II ions (25.2–30.6 cm 3 K mol –1 ) with spin–orbit coupling . On cooling, the χ m T plots of 2 have a minimum like a ferrimagnetic behavior.…”

“…The χ m T products of 2 are different from that of 1, which decreases slowly on cooling with a minimum at about 44 K and then increases rapidly to a maximum at about 3.6 K. The magnetic data of 2 in the specific range are fitted according to the Curie−Weiss law (Figure 4c), which gives C = 42.07 cm 3 K mol −1 and θ = −0.10 K. The Curie constant is consistent with the value of one Dy III ion ( 6 H 15/2 and g = 4/3 14.17 cm 3 K mol −1 ) and nine Co II ions (25.2−30.6 cm 3 K mol −1 ) with spin−orbit coupling. 49 On cooling, the χ m T plots of 2 have a minimum like a ferrimagnetic behavior. However, by comparing the magnetic data and the behavior of 1 and 2, it is found that the initial decrease of the χ m T products on cooling of 2 is due to the depopulation of the Stark levels of the Dy III ion.…”

Modulating the structural topologies from star-shape to cross-shape for Co–Dy heterometallic complexes with slow magnetic relaxation behavior

“…To eliminate the magnetic coupling between Co II and Dy III , researchers recently have seemed to transfer their attention to Co III -Dy SMMs. To date, about forty Co III -Dy complexes with different topologies have been reported, including {Co III -Dy III }, 21 {Co III DyDy III 3 }, 22 {Co III 2 Dy III }, 23 butterfly or linear {Co III 2 Dy III 2 }, [24][25][26][27][28][29][30] {Co III 2 Dy III 4 }, 31 {Co III 4 Dy III 2 }, 32 {Co III 4 Dy III 3 }, 33 and {Co III 4 Dy III 4 }. 34 In these SMM complexes, the butterfly {Co III 2 Dy III 2 } complexes have been intensively investigated by many research groups, with U eff values of 14-170 K. [24][25][26][27][28] These imply that, except for regulating the coordination environment of Dy III and the magnetic coupling between paramagnetic ions based on some well-known topologies like Co III 2 Dy III 2 , [24][25][26][27][28] modulation of the structural topologies of Co II -Dy and Co III -Dy has always received considerable attention.…”

Field induced slow magnetic relaxation in a zig-zag chain-like Dy(iii) complex with the ligando-phenylenedioxydiacetato

“…By way of example, we can mention a dinuclear complex [Dy 2 Lz 2 (C 6 H 5 CO 2 ) 6 ]•2CH 3 CN (Lz = 6-pyridin-2-yl-[1,3,5]triazine-2,4-diamine), 27 ] condensation product of 3methoxysalicylaldehyde and 2-amino-2-methyl-1-propanol). 29 We note that in both analogous Dy(III) complexes containing PDOA ligands, [Dy 2 ] n and ([Dy 2 ], only two relaxation processes were observed. 6g The fitted data was used in constructing the Argand diagram (Fig.…”