Hysteresis Photomodulation via Single-Crystal-to-Single-Crystal Isomerization of a Photochromic Chain of Dysprosium Single-Molecule Magnets

Abstract

A one-dimensional coordination solid is synthesized by reaction of a bispyridyl dithienylethene (DTE) photochromic unit with the highly anisotropic dysprosium-based single-molecule magnet [Dy(Tppy)F(pyridine)2]PF6. Slow magnetic relaxation characteristics are retained in the chain compound, 1c, and photoisomerization of the bridging DTE ligand induces a single-crystal-to-single-crystal transformation that can be monitored using photocrystallography. Notably, the resulting chain compound 1o exhibits faster low-temperature relaxation than 1c, which is apparent in magnetic hysteresis data collected for both compounds as high as 4 K. Ab initio calculations suggest that this photomodulation of the magnetic relaxation behavior is due to crystal packing changes rather than changes to the crystal field splitting upon ligand isomerization.

Coordination-enhanced photochromism in dysprosium dinuclear complexes with photomodulated single-molecule magnet behavior

“…Moreover, as observed in our previous studies, these magnetic measurements confirm that the effect of photoconversion on the SMM behavior of magnetic molecules has to be investigated on comparable sampling, i.e. single crystals when single-crystal to single-crystal photoconversion is observed [40] or evaporated solution when photoconversion occurs at the liquid state [53]. Table S10.…”

“…We specifically target lanthanide-based complexes since their magnetic properties clearly stand out from those of transitionmetal complexes [39]. We previously obtained hysteresis photomodulation in DAE-dysprosium 1D assemblies [40] and decided to further investigate dinuclear complexes bridged by a DAE. Hence, we report here i) a newly synthesized pyrazine-based bis-tridentate DAE ligand and the corresponding dinuclear yttrium and dysprosium complexes that all show T-type photochromism, ii) large changes in the photochromic behaviour induced by metal coordination, with a tuning of the bleaching rate by several orders of magnitude characterized through VT-NMR and supported by theoretical calculations, and iii) the photomodulation of the resulting SMM properties upon photoisomerization, that is further analyzed through ab initio calculations.…”

Thermo- and light-triggered reversible interconversion of dysprosium–anthracene complexes and their responsive optical, magnetic and dielectric properties

“…For example, luminescent lanthanide-based single molecule magnets (Ln-SMMs) are promising bifunctional materials. [17][18][19][20] Although their SMM behavior can be sensitive to light, 21 solvent, [22][23][24] redox, 25,26 and mechanical force, 27,28 it is extremely difficult to modulate the luminescence and magnetism of Ln-SMMs synergistically. In particular, switchable Ln-SMMs with additional dielectric properties remain elusive.…”

Pseudo-Tetrahedral vs Pseudo-Octahedral ErIII Single Molecule Magnets and the 'Disruptive' Role of Coordinated TEMPO Radicals

“…This led already to significant breakthroughs. 11,[14][15][16][17] The second, even more challenging goal, is achieving a certain degree of control over the nanomagnetism of these assemblies via external stimuli lading to the ON/OFF switching [18][19][20][21][22][23] and in the long-run -the multifunctionality, so that they can perform many different functions depending on their environment and thermodynamic conditions. [24][25][26] Usually, the lanthanide of choice for the design of highperformance SMMs is a Kramers ion Dy due to its large magnetic moment and high magnetic anisotropy.…”