New Family of Lanthanide-Based Complexes with Different Scorpionate-Type Ligands: A Rare Case Where Dysprosium and Ytterbium Analogues Display Single-Ion-Magnet Behavior

Abstract

A new family of lanthanide complexes [Ln(Tpz)2Bpz]·xCH2Cl2 (Ln = Gd, Tb, Dy, Ho, x = 0.5; Ln = Yb, x = 1; Tpz = hydrotris(pyrazolyl)borate; Bpz = dihydrobis(pyrazolyl)borate) has been synthesized. Those complexes have been characterized by single-crystal X-ray diffraction, and the magnetic properties have been investigated. Both dysprosium and ytterbium analogues display single-ion-magnet behavior, despite the difference in their spatial distribution of 4f electronic charges. Theoretical calculations with crystal field parameters have been carried out to gain better insight of the relaxation pathways that may be involved in those two complexes.

Slow Magnetic Relaxation in Unprecedented Mono-Dimensional Coordination Polymer of Ytterbium Involving Tetrathiafulvalene-Dicarboxylate Linker

“…In this way, the best candidates for each category are the oblate Dy III ion when the ligand charge distribution is axial and the prolate Yb III ion when this distribution is planar. Moreover lanthanide emission properties were recently exploited in this respect as a probe of the ligand field splitting in SMM [4][5][6][7][8][9][10][11][12]. The versatility of ligand chemistry allows adding one or more physical properties to the SMM behavior [13,14].…”

A Unique LnIII{[3.3.1]GaIII Metallacryptate} Series That Possesses Properties of Slow Magnetic Relaxation and Visible/Near‐Infrared Luminescence

“…The small 750 Oe applied field selection is described in the supplemental information (Figure S13, Supporting Information). In a 0 Oe applied field, the χ“m increases slightly at temperatures below 10 K, but no peak maxima are present, a prevalent observation of lanthanide SIMs . However, under the 750 Oe applied field, the χ”m signal rises significantly between 7–9 K and peak maxima were observable due to the suppression of QTM.…”

“…Work by Lannes and Luneau show similar phenomena for slow magnetization relaxations in nine‐coordinate tricapped‐trigonal prism dysprosium(III) and ytterbium(III) complexes, [Ln(Tpz) 2 Bpz]⋅ x CH 2 Cl 2 . Based on crystal‐field calculations of the pyrazolyl borates it was determined that the relaxation of the Dy III in [Dy(Tpz) 2 Bpz]⋅ x CH 2 Cl 2 was consistent with a thermally driven Orbach process, while the one of the Yb III ion was better described by a Raman process, rendering any effective barrier to magnetization relaxation an artifact of the applied field . In addition, tris‐oxydiacetate complexes of dysprosium(III) and erbium(III) were characterized by Coronado and co‐workers .…”

“…In a0Oe applied field, the c"m increases slightly at temperatures below 10 K, but no peak maximaa re present, ap revalent observation of lanthanide SIMs. [24,61,[65][66][67] However,u nder the 750 Oe appliedf ield, the c"m signalr ises significantly between 7-9 Ka nd peak maxima were observable due to the suppression of QTM. Fitting the temperature dependent data from 208 to 1399 Hz to aL orenzian function c 00 m ¼ a= 1 þ T À T 0 ðÞ =b ðÞ 2 ðÞ ÀÁ allowed for the generation of an Arrhenius plot (Figure 8), which was fit to the Arrhenius Law (ln(1/t) = ln(1/t 0 )-U eff /k B ·T).…”

“…[66] Based on crystal-field calculations of the pyrazolyl boratesi tw as determined that the relaxation of the Dy III in [Dy(Tpz) 2 Bpz]·xCH 2 Cl 2 was consistent with at hermally driven Orbach process, while the one of the Yb III ion was better described by aR aman process,r enderinga ny effective barriert om agnetization relaxation an artifacto ft he applied field. [66] In addition, tris-oxydiacetate complexeso fd ysprosium(III) and erbium(III) were characterized by Coronado and coworkers. [68] In this case the Dy III and Er III complexes demonstrated frequency dependent c"r esponses both in the presence and absence of an applied 1000 Oe field.…”