Retraction: “Comparison of ensemble and single molecule approaches to probing polymer relaxation dynamics near Tg” [J. Chem. Phys. 116, 5850 (2002)]

2006 ◽  
Vol 124 (16) ◽  
pp. 169901
Author(s):  
Laura A. Deschenes ◽  
David A. Vanden Bout
2017 ◽  
Vol 53 (14) ◽  
pp. 2283-2286 ◽  
Author(s):  
Brian S. Dolinar ◽  
Silvia Gómez-Coca ◽  
Dimitris I. Alexandropoulos ◽  
Kim R. Dunbar

Addition of a radical to the bridging tetrazine ligand of a Dy2 complex dramatically alters the magnetic properties. The radical complex undergoes magnetic relaxation via a thermal relaxation pathway, whereas the neutral compound relaxes via quantum tunneling of the magnetization.


2014 ◽  
Vol 597 ◽  
pp. 158
Author(s):  
Christian Braun ◽  
Susanne Pietsch ◽  
Sebastian Proch ◽  
Young Dok Kim ◽  
Gerd Ganteför

2021 ◽  
Author(s):  
Daniel Reta ◽  
Jon G. C. Kragskow ◽  
Nicholas Chilton

<p>Organometallic molecules based on [Dy(Cp<sup>R</sup>)<sub>2</sub>]<sup>+</sup> cations have emerged as clear front-runners in the search for high-temperature single-molecule magnets. However, despite a growing family of structurally-similar molecules, these molecules show significant variations in their magnetic properties, demonstrating the importance of understanding magneto-structural relationships towards developing more efficient design strategies. Here we refine our <i>ab initio</i> spin dynamics methodology and show that it is capable of quantitative prediction of relative relaxation rates in the Orbach region. Applying it to all reported [Dy(Cp<sup>R</sup>)<sub>2</sub>]<sup>+</sup> cations allows us to tease out differences in their relaxation dynamics, highlighting that the main discriminant is the magnitude of the crystal field splitting. We subsequently employ the method to predict relaxation rates for a series of hypothetical organometallic sandwich compounds, revealing an upper limit to the effective barrier to magnetic relaxation of around 2200 K, which has been reached. However, we show that further improvements to single-molecule magnets can be made by moving vibrational modes off-resonance with electronic excitations.</p>


2020 ◽  
Vol 26 (35) ◽  
pp. 7774-7778 ◽  
Author(s):  
Vijay S. Parmar ◽  
Fabrizio Ortu ◽  
Xiaozhou Ma ◽  
Nicholas F. Chilton ◽  
Rodolphe Clérac ◽  
...  

2020 ◽  
Author(s):  
Katie L. M. Harriman ◽  
Jesse Murillo ◽  
Elizaveta A. Suturina ◽  
Skye Fortier ◽  
Muralee Murugesu

<p>Utilizing a terphenyl bisanilide ligand, two Dy(III) complexes [K(DME)<sub>x</sub>][L<sup>Ar</sup>Dy(X)<sub>2</sub>] (L<sup>Ar</sup> = {C<sub>6</sub>H<sub>4</sub>[(2,6-<i><sup>i</sup></i>PrC<sub>6</sub>H<sub>3</sub>)NC<sub>6</sub>H<sub>4</sub>]<sub>2</sub>}<sup>2-</sup>), X = Cl (<b>1</b>) and X = I (<b>2</b>) were synthesized. The ligand imposes an unusual see-saw shaped molecular geometry leading to a coordinatively unsaturated complex with near-linear N-Dy-N (avg. 159.9° for<b>1</b> and avg. 160.3<sup>o</sup> for <b>2</b>) bond angles. These complexes exhibit Single-Molecule Magnet (SMM) behavior with significant uniaxial magnetic anisotropy as a result of the transverse coordination of the bisanlide ligand which yields high energy barriers to magnetic spin reversal of <i>U</i><sub>eff</sub> = 1334 K/ 927cm<sup>-1</sup> (<b>1</b>) and 1299 K/ 903 cm<sup>-1</sup> (<b>2</b>) in zero field. Magneto-structural correlations are discussed with the goal of finding a link between halide ancillary ligands in the structurally analogous complexes and the through barrier relaxation dynamics observed in the ac magnetic susceptibility, despite the similar dc magnetic susceptibility for compounds <b>1</b> and <b>2</b>. <i>Ab initio</i> calculations reveal that the dominant crystal field of the bisanilide ligand controls the orientation of the main magnetic axis which runs nearly parallel to the N-Dy-N bonds, and defines the height of the energy barrier. Thus, further validating the use of transverse ligands to enhance the SMM properties of Dy(III) ions.</p>


2009 ◽  
Vol 131 (34) ◽  
pp. 12201-12210 ◽  
Author(s):  
Els Braeken ◽  
Gert De Cremer ◽  
Philippe Marsal ◽  
Gérard Pèpe ◽  
Klaus Müllen ◽  
...  

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