TY - JOUR
T1 - Enhancing Magnetic Hysteresis in Single-Molecule Magnets by Ligand Functionalization
AU - Yu, Ke-xin
AU - Kragskow, Jon G.c.
AU - Ding, You-song
AU - Zhai, Yuan-qi
AU - Reta, Daniel
AU - Chilton, Nicholas F.
AU - Zheng, Yan-zhen
N1 - We acknowledge the Natural Science Foundation of China (21620102002 and
21773130), Xi’an Municipal Bureau of Science and Technology (201805056ZD7CG40), Cyrus Chung Ying Tang Foundation, State Key Laboratory for Mechanical Behavior of Materials, the Fundamental Research Funds for the Central Universities (P.R.C.), EPSRC (U.K., EP/P002560/1), and the University of Manchester for funding and support. We also thank the Instrument Analysis Centre of Xi’an Jiaotong University for the measurement on dilution ratio and the Computational Shared Facility at The University of Manchester. K.-X.Y. thanks the China Scholarship Council for a research scholarship and N.F.C. thanks the University of Manchester for a Presidential Fellowship and the Royal Society for a University Research Fellowship. We thank Prof. Richard Winpenny and Dr David
Mills for useful discussions
PY - 2020/5/28
Y1 - 2020/5/28
N2 - Design criteria for dysprosium(III) single-molecule magnets (SMMs) with large thermal energy barriers to magnetic reversal have been established and proven, and the challenge to enhance performance is in understanding and controlling electron-vibration coupling that is the origin of magnetic reversal. We have prepared an SMM, [Dy(L)2(py)5][BPh4] 1 (HL = (S)-(-)-1-phenylethanol), based on the archetype [Dy(OtBu)2(py)5][BPh4] 2. Compounds 1 and 2 have similarly large energy barriers of Ueff = 1,130(20) cm−1 and Ueff = 1,250(10) cm−1, and yet 1 shows magnetic hysteresis at a far higher temperature of 22 K cf. TH = 4 K for 2. Ab initio calculation of the electron-vibration coupling and spin dynamics shows that substitution of the alkoxide ligand in fact enhances relaxation over the energy barrier for 1 compared with 2, in agreement with experiment, and that the higher temperature of magnetic hysteresis likely owes to reduced quantum tunneling at low temperatures.
AB - Design criteria for dysprosium(III) single-molecule magnets (SMMs) with large thermal energy barriers to magnetic reversal have been established and proven, and the challenge to enhance performance is in understanding and controlling electron-vibration coupling that is the origin of magnetic reversal. We have prepared an SMM, [Dy(L)2(py)5][BPh4] 1 (HL = (S)-(-)-1-phenylethanol), based on the archetype [Dy(OtBu)2(py)5][BPh4] 2. Compounds 1 and 2 have similarly large energy barriers of Ueff = 1,130(20) cm−1 and Ueff = 1,250(10) cm−1, and yet 1 shows magnetic hysteresis at a far higher temperature of 22 K cf. TH = 4 K for 2. Ab initio calculation of the electron-vibration coupling and spin dynamics shows that substitution of the alkoxide ligand in fact enhances relaxation over the energy barrier for 1 compared with 2, in agreement with experiment, and that the higher temperature of magnetic hysteresis likely owes to reduced quantum tunneling at low temperatures.
U2 - 10.1016/j.chempr.2020.04.024
DO - 10.1016/j.chempr.2020.04.024
M3 - Article
SN - 2451-9294
VL - 6
SP - 1777
EP - 1793
JO - Chem
JF - Chem
IS - 7
ER -