Sublimable Single Ion Magnets Based on Lanthanoid Quinolinate Complexes: The Role of Intermolecular Interactions on Their Thermal Stability

Abstract

We report the design, preparation and characterization of two families of thermally robust coordination complexes based on lanthanoid quinolinate compounds: [Ln(5,7-Br 2 q) 4 ]and [Ln(5,7-ClIq) 4 ] -, where q = 8-hydroxyquinoline and Ln = Dy III , Tb III , Er III and Ho III . Samples of [Dy(5,7-Br 2 q) 4 ]decompose upon sublimation, whereas the sodium salt of [Dy(5,7-ClIq) 4 ] -, which displays subtly different crystalline interactions, is sublimable under gentle conditions. The resulting film presents low roughness with high coverage and the molecular integrity of the coordination complex is verified through AFM, MALDI-TOF, FT-IR and microanalysis. Crucially, the single-molecule magnet behavior exhibited by [Dy(5,7-ClIq) 4 ]in bulk remains detectable by ac magnetometry in the sublimated film.

Pentanuclear Spirocyclic Ni4Ln Derivatives: Field Induced Slow Magnetic Relaxation in the Dysprosium and Erbium Analogues

“…On decreasing the temperatures, the susceptibility stays constant until 180 K, then the value decreases to 3.84 emu K mol –1 at 2 K. For 4 , the susceptibility value at room temperature is close to the expected for four Ni II centres and one Dy III ( S = 5/2, L = 5, 6 H 15/2 , g = 4/3, χT = 14.17 emu K mol –1 ) of 18.17 emu K mol –1 , being the experimental value of χT = 17.93 emu K mol –1 and for 5 , the same tendency is observed with an experimental χT value of 15.35 emu K mol –1 , in which, the expected value is 15.48 emu K mol –1 since Er III ( S = 3/2, L = 6, 4 I 15/2 , g = 36/5, χT = 11.48 emu K mol –1 ). At low temperatures the χT values for 4 and 5 steadily decrease due to the thermal depopulation of the Stark sublevels and/or to the presence of intermolecular interactions that can exist in the molecule . The experimental values of all the compounds are close to the expected values of non‐interacting paramagnetic centres (Ni 4 Ln) as has been reported for other similar systems…”

“…At low temperatures the T values for 4 and 5 steadily decrease due to the thermal depopulation of the Stark sublevels and/or to the presence of intermolecular interactions that can exist in the molecule. [74] The experimental values of all the compounds are close to the expected values of noninteracting paramagnetic centres (Ni 4 Ln) as has been reported for other similar systems. [75] Figure 5.…”

Mononuclear Dysprosium Alkoxide and Aryloxide Single‐Molecule Magnets

“…Tb SMMsw ith higher CNs with mainly multi-dentate chelating aryloxide ligandsh ave been investigated. [85,95,[131][132][133] However, they do not show ar emarkable improvement over their Dy and Pc counterparts. [130,133] Ho III SMMsr emainr elatively unexplored despite having the highest possible magnetic spin ground state ( 5 I 8 : m J = AE 8) amongst all the Ln III ions.…”

“…There has been no Tb alkoxide or aryloxide SMM with CN <6 in the literature to date. Tb SMMs with higher CNs with mainly multi‐dentate chelating aryloxide ligands have been investigated [85, 95, 131–133] . However, they do not show a remarkable improvement over their Dy and Pc counterparts [130, 133] …”

Hybrid organic–inorganic mononuclear lanthanoid single ion magnets

“…3 After this seminal contribution, different types of Ln molecular complexes with SIM behaviour have been obtained through a rational approach using coordination chemistry. 4,5 Most of these compounds are based on organic ligands, [6][7][8] allowing a finetuning of the dynamic response through chemical modification of the organic moieties, 9 and can find applications as spin valves and qubits. 8,10 The inorganic analogues, i.e., mononuclear SIMs in which the organic ligands have been replaced by inorganic ones, have also been described using different types of lacunary polyoxometalates (LPOMs), [11][12][13][14][15] resulting in more robust systems with applications in quantum computation; 16,17 this is a consequence of the magnetic insulation from the other neighbouring magnetic molecules of the crystal lattice caused by the inorganic moieties.…”