New Dioximes as Bridging Ligands in 3d/4f-Metal Cluster Chemistry: One-Dimensional Chains of Ferromagnetically Coupled {Cu₆Ln₂} Clusters Bearing Acenaphthenequinone Dioxime and Exhibiting Magnetocaloric Properties

Abstract

The employment of the tetradentate ligand acenaphthenequinone dioxime (acndH2) for a first time in heterometallic CuII/LnIII (Ln = Gd and Dy) chemistry has afforded the one-dimensional coordination polymers [Cu6Gd2(acnd)6­(acndH)6­(MeOH)6] n (1) and [Cu6Dy2(acnd)6­(acndH)6­(MeOH)2] n (2), which consist of repeating {Cu6Ln2} clusters that are intermolecularly linked to each other through the oximate groups of two η2:η1:η1:μ3 acnd2– ligands. The [Cu6Ln2­(μ3-NO)6­(μ-NO)8]4+ core is unprecedented in heterometallic cluster chemistry and comprises two symmetry-related {Cu3Ln} subunits, each with a distorted trigonal pyramidal topology. Magnetic susceptibility studies revealed the presence of predominant ferromagnetic exchange interactions within the {Cu3Ln} subunits and weak antiferromagnetic interactions between them. As a result, the magnetic and magnetocaloric properties of the {Cu6Gd2} n compound could be rationalized in terms of two weakly coupled S = 5 spins that yield a magnetic entropy change of −ΔS m = 11.8 J kg–1 K–1 at T = 1.6 K for μ0ΔH = 7 T.

A Water Stable CdII‐based Metal‐Organic Framework as a Multifunctional Sensor for Selective Detection of Cu2+ and Cr2O72– Ions

“…With all that in mind, to explore new luminescent materials, which are capable of selective recognition of cations and anions, has always been of vital importance both in theory and applications. Metal‐organic frameworks (MOFs), which are formed by metal ions and organic ligand, are currently of great interest to researchers in past decades for their rich compositional and structural diversity and wide utilization in catalysis, electronics, optics, magnetism, gas storage and separation, luminescence‐based sensing and detection . The design and synthesis of MOFs have been a focus in the field to regulate the structures and properties and, at the same time, was influenced by a number of factors, such as the solvent preference, the coordination nature of metal ions, the organic ligand, the reaction temperature, the pH and the ligand‐metal ratios .…”

Oximato-Based Ligands in 3d/4f-Metal Cluster Chemistry: A Family of {Cu3Ln} Complexes with a “Propeller”-like Topology and Single-Molecule Magnetic Behavior

“…Our group has had a longstanding interest in the synthesis and use of new mono- and dioximato chelates as a means of isolating heterometallic complexes with unprecedented topologies and nontrivial physicochemical properties (i.e., magnetic, optical, and catalytical) . To this end, we recently reported a series of new Cu II /Ln III clusters of different nuclearities (i.e., {Cu 6 Ln 12 } and {Cu 6 Ln 2 }) and topologies from the use of 2,6-diacetyl­pyridine dioxime (dapdoH 2 ) and ace­naph­thene­quinone dioxime (acndH 2 ), respectively (Scheme ).…”

Double-Propeller-like Heterometallic 3d–4f Clusters Ln18Co7

“…For compound 2, the M value observed at 7 T reaches 106.8 Nμ B , much lower than the saturation 183 Nμ B obtained for 18 Dy 3+ ions and one Co 2+ ion (Figure b). Moreover, at 2, 3, and 5 K, the M versus H / T plots are not superimposed on a single master curve (Figure S10), suggesting the existence of significant magnetic anisotropy or low-lying excited states . Moreover, to investigate the dynamic magnetization of compound 2 , the alternating current (ac) susceptibilities were recorded at 2–10 K under zero-dc field.…”