Single-molecule magnets are compounds that exhibit magnetic bistability caused by an energy barrier for the reversal of magnetization (relaxation). Lanthanide compounds are proving promising as single-molecule magnets: recent studies show that terbium phthalocyanine complexes possess large energy barriers, and dysprosium and terbium complexes bridged by an N2(3-) radical ligand exhibit magnetic hysteresis up to 13 K. Magnetic relaxation is typically controlled by single-ion factors rather than magnetic exchange (whether one or more 4f ions are present) and proceeds through thermal relaxation of the lowest excited states. Here we report polylanthanide alkoxide cage complexes, and their doped diamagnetic yttrium analogues, in which competing relaxation pathways are observed and relaxation through the first excited state can be quenched. This leads to energy barriers for relaxation of magnetization that exceed 800 K. We investigated the factors at the lanthanide sites that govern this behaviour.

A family of [MIII2MII3]n+ trigonal bipyramidal cages are characterised in the solution and solid state.

In-situ single-crystal diffraction and spectroscopic techniques have been used to study a previously unreported Cu-framework bis[1-(4-pyridyl)butane-1,3-dione]copper(II) (CuPyr-I). CuPyr-I was found to exhibit high-pressure and low-temperature phase transitions, piezochromism, negative linear...

The reaction of the simple metalloligand [FeL] [HL = 1-(4-pyridyl)butane-1,3-dione] with a variety of different M salts results in the formation of a family of heterometallic cages of formulae [FePdL]Cl (1), [FeCuL(HO)Br]Br (2), [FeCuL(HO)](NO) (3), [FeNiL(SCN)Cl] (4), and [FeCoL(SCN)(HO)]Cl (5). The metallic skeleton of each cage describes a cube in which the Fe ions occupy the eight vertices and the M ions lie at the center of the six faces. Direct-current magnetic susceptibility and magnetization measurements on 3-5 reveal the presence of weak antiferromagnetic exchange between the metal ions in all three cases. Computational techniques known in theoretical nuclear physics as statistical spectroscopy, which exploit the moments of the Hamiltonian to calculate relevant thermodynamic properties, determine J = 0.10 cm for 3 and J = 0.025 cm for 4. Q-band electron paramagnetic resonance spectra of 1 reveal a significantly wider spectral width in comparison to [FeL], indicating that the magnitude of the Fe zero-field splitting is larger in the heterometallic cage than in the monomer.