Soft magnetic hysteresis in a dysprosium amide-alkene complex up to 100 kelvin.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40562922.
- Also identified by DOI 10.1038/s41586-025-09138-0 and PMC identifier 12221970.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Lanthanides have shown magnetic memory at both the atomic<sup>1,2</sup> and molecular<sup>3,4</sup> level. The magnetic remanence temperatures of lanthanide single-molecule magnets can surpass d-transition metal examples<sup>5,6</sup>, and since 2017, energy barriers to magnetic reversal (U<sub>eff</sub>) from 1,237(28) cm<sup>-1</sup> to 1,631(25) cm<sup>-1</sup> and open magnetic hysteresis loops between 40 K and 80 K have typically been achieved with axial dysprosium(III) bis(cyclopentadienyl) complexes<sup>7-17</sup>. It has been predicted that linear dysprosium(III) compounds could deliver greater m<sub>J</sub> (the projection of the total angular momentum, J, on a quantization axis labelled z) state splitting and therefore higher U<sub>eff</sub> and hysteresis temperatures<sup>18-21</sup>, but as lanthanide bonding is predominantly ionic<sup>22,23</sup>, so far dysprosium bis(amide) complexes have shown highly bent geometries that promote fast magnetic reversal<sup>24,25</sup>. Here we report a dysprosium bis(amide)-alkene complex, [Dy{N(Si<sup>i</sup>Pr<sub>3</sub>)[Si(<sup>i</sup>Pr)<sub>2</sub>C(CH<sub>3</sub>)=CHCH<sub>3</sub>]}{N(Si<sup>i</sup>Pr<sub>3</sub>)(Si<sup>i</sup>Pr<sub>2</sub>Et)}][Al{OC(CF<sub>3</sub>)<sub>3</sub>}<sub>4</sub>] (1-Dy), that shows U<sub>eff</sub> = 1,843(11) cm<sup>-1</sup> and slow closing of soft magnetic hysteresis loops up to 100 K. Calculations show that the U<sub>eff</sub> value for 1-Dy arises from the charge-dense amide ligands, with a pendant alkene taking a structural role to enforce a large N-Dy-N angle while imposing only a weak equatorial interaction. This leads to molecular spin dynamics up to 100 times slower than the current best single-molecule magnets above 90 K.