Exploring structural, magnetic, and catalytic diversity in tetranuclear {CuO} cubane cores and a dinuclear complex derived from closely related ligand systems.

The coordination compounds featuring a {CuO} core, typically bridged by hydroxo or alkoxo groups, are particularly intriguing due to their notable magnetic properties and catalytic activity. In this study, we explored the synthesis and characterization of four new Schiff base ligands and their subsequent complexation with Cu salts, which resulted in the formation of three tetranuclear complexes: [Cu(L)]·2HO (1), [Cu(L)(HL)](Cl)(NO)·5HO (2), and [Cu(L)] (3), as well as one dinuclear complex: [Cu(L)] (4). These tetranuclear complexes all feature a {CuO} core, but with differing coordination environments around the Cu centers.

A Nanosized {Ni } Cluster with a 'Flying Saucer' Topology Exhibiting Slow Relaxation of Magnetisation Phenomena at Both 15 K and 1.3 K.

A high-nuclearity {Ni} complex (1) with a unique 'flying saucer' motif has been prepared from the organic chelate, α-methyl-2-pyridine-methanol (mpmH), in conjunction with bridging azido (N ) and peroxido (O ) ligands. Magnetic susceptibility measurements revealed the presence of both ferro- and antiferromagnetic exchange interactions between the metal centres in 1, and the stabilization of spin states with appreciable S values at two different temperature regimes. The end-on bridging azido and alkoxido groups are in all likelihood the ferromagnetic mediators, while the η:η:μ-bridging peroxides most likely promote the antiparallel alignment of the metals' spin vectors, yielding an overall non-zero spin ground state for the centrosymmetric compound 1.

Family of Quasi-Isotropic Mn and Mn Complexes Exhibiting Slow Relaxation of the Magnetization.

Slow relaxation of magnetization has been studied for a family of mononuclear Mn complexes and one ferromagnetic dinuclear system, all of them presenting very weak anisotropy. Complexes with formula [{NiL1Mn(HO)(MeOH)}{NiL1}](ClO) (), [Mn{NiL1}](ClO) (), [Mn{NiL2}](ClO) (RR-L2, RR, SS-L2, SS), [Mn{NiL3}](ClO) (RR-L3, RR, SS-L3, SS) and (μ-N)[NiMn(L1)(N)] () are derived from compartmental Schiff bases, in which the Ni environment is square planar and thus diamagnetic. All of the systems have been structurally and magnetically characterized.

Slow Magnetic Relaxation in Silver(II) Macrocyclic Systems.

The spin-lattice relaxation time has been studied trough alternating-current susceptometry and ultralow-frequency Raman spectroscopy in a family of silver(II)-derived molecular systems with spin / and formulas [Ag(-CTH)(NO)] () and [Ag(-CTH)(ClO)] (), where CTH = -5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane. The combination of both techniques demonstrates the occurrence of slow spin magnetic relaxation induced by spin-phonon interaction. The magnetic behavior of these silver(II)-derived systems opens the door to a new cation in the scarce family of = / systems with slow relaxation of magnetization.

Interesting chemical and physical features of the products of the reactions between trivalent lanthanoids and a tetradentate Schiff base derived from cyclohexane-1,2-diamine.

The initial use of a tetradentate Schiff base (LH) derived from the 2 : 1 condensation between 2-hydroxyacetophenone and cyclohexane-1,2-diamine in 4f-metal chemistry is described. The 1 : 2 reaction of Ln(NO)·HO (Ln = lanthanoid or yttrium) and LH in MeOH/CHCl has provided access to isostructural complexes [Ln(NO)(L'H)(MeOH)] in moderate to good yields. Surprisingly, the products contain the corresponding Schiff base ligand L'H possessing six aliphatic -CH- groups instead of the -CH-(CH)-CH- unit of the cyclohexane ring, an unusual ring-opening of the latter has occurred.