Isotopically enriched polymorphs of dysprosium single molecule magnets.

A triclinic polymorph Dy(t) and a monoclinic polymorph Dy(m) of [Dy(tta)3(L)] with L = 4-[6-(1,3-benzothiazol-2-yl)pyridin-3-yl]-4',5'-bis(methylthio)tetrathiafulvene behave as Single-Molecule Magnets with hysteresis loops opened at zero field. Magnetic properties were enhanced through magnetic dilution and 164Dy isotopic enrichment which definitively support the importance of isotopes for the control of quantum magnets.

Improved slow magnetic relaxation in optically pure helicene-based DyIII single molecule magnets.

Racemic and optically pure [Dy(hfac)3(L)] complexes with L = 3-(2-pyridyl)-4-aza[6]-helicene have been synthesized and characterized. Both the racemic and enantiopure forms behave as single molecule magnets in their crystalline phase, while electronic circular dichroism activity is evidenced. Ab initio calculations on isolated complexes followed by the determination of intermolecular dipolar couplings allowed the rationalization of the different low-temperature magnetic behaviours. The enantiopure SMM differs from the racemic one by the presence of a hysteresis loop in the former system.

A solid state highly emissive Cu(i) metallacycle: promotion of cuprophilic interactions at the excited states.

The straightforward synthesis of a new Cu(i) metal-rich small metallacycle is presented. This compound is luminescent in the solid state with an emission quantum yield of 72% at room temperature and displays a pronounced reversible red-shift of its emission spectra upon cooling. Quantum chemical calculations reveal that these properties are governed by important geometrical relaxations that imply the formation of cuprophilic interactions at the excited states.

Thermal and near-infrared light induced spin crossover in a mononuclear iron(ii) complex with a tetrathiafulvalene-fused dipyridophenazine ligand.

A mononuclear Fe(ii) complex involving a tetrathiafulvalene-based ligand exhibits thermal spin-crossover (around 143 K) with pronounced hysteresis behaviour (48 K). The chromophoric and π-extended ligand allows Near-Infrared (NIR) sensitization for the light-induced excited spin-state trapping (LIESST) with T(LIESST) = 90 K.

Analysis of the electrostatics in Dy(III) single-molecule magnets: the case study of Dy(Murex)3.

A Dy(III)-based single-molecule magnet is reported. Ab initio calculations highlight that molecular symmetry plays a predominant role over site symmetry in determining the shape and orientation of Dy(III) magnetic anisotropy. Moreover the dipolar component of the electrostatic potential created by the surrounding ligands is shown to be the driving force of its magnetic behaviour.