TY - JOUR

T1 - Tunable valence tautomerism in lanthanide–organic alloys

AU - Dunstan, Maja A.

AU - Manvell, Anna S.

AU - Yutronkie, Nathan J.

AU - Aribot, Frédéric

AU - Bendix, Jesper

AU - Rogalev, Andrei

AU - Pedersen, Kasper S.

N1 - Funding Information: K.S.P. thanks the VILLUM Foundation for a VILLUM Young Investigator (42094) grant, the Independent Research Fund Denmark for a DFF-Sapere Aude Starting grant (no. 0165-00073B) and the Carlsberg Foundation for a research infrastructure grant (no. CF17-0637). The X-ray spectroscopy experiments were performed at the ID12 beamline at the European Synchrotron Radiation Facility (Grenoble, France). We thank the Danish Agency for Science, Technology, and Innovation for funding the instrument centre Danscatt. + Publisher Copyright: © The Author(s), under exclusive licence to Springer Nature Limited 2024.

PY - 2024

Y1 - 2024

N2 - The inimitable electronic structures of the lanthanide (Ln) ions are key to advanced materials and technologies involving these elements. The trivalent ions are ubiquitous and are used much more widely than the divalent and tetravalent analogues, which possess vastly different optical and magnetic properties. Hence, alteration of the valence electron count by external stimuli can lead to dramatic changes in materials properties. Compounds exhibiting a temperature-induced complete Ln(III) ⇄ Ln(II) switch, referred to as a valence tautomeric (VT) transition, are rare. Here we present an abrupt and hysteretic VT transition in a lanthanide-based coordination polymer, SmI2(pyrazine)3, driven by the interconversion of Sm(II)–pyrazine(0) and Sm(III)–pyrazine(·−) redox pairs. Alloying SmI2(pyrazine)3 with Yb(II) yields isomorphous Sm1–xYbxI2(pyrazine)3 solid solutions with VT transition critical temperatures ranging widely from 200 K to ∼50 K at ambient pressure. These findings demonstrate a simple strategy to realize thermally switchable magnetic materials with chemically tunable transition temperatures. (Figure presented.)

AB - The inimitable electronic structures of the lanthanide (Ln) ions are key to advanced materials and technologies involving these elements. The trivalent ions are ubiquitous and are used much more widely than the divalent and tetravalent analogues, which possess vastly different optical and magnetic properties. Hence, alteration of the valence electron count by external stimuli can lead to dramatic changes in materials properties. Compounds exhibiting a temperature-induced complete Ln(III) ⇄ Ln(II) switch, referred to as a valence tautomeric (VT) transition, are rare. Here we present an abrupt and hysteretic VT transition in a lanthanide-based coordination polymer, SmI2(pyrazine)3, driven by the interconversion of Sm(II)–pyrazine(0) and Sm(III)–pyrazine(·−) redox pairs. Alloying SmI2(pyrazine)3 with Yb(II) yields isomorphous Sm1–xYbxI2(pyrazine)3 solid solutions with VT transition critical temperatures ranging widely from 200 K to ∼50 K at ambient pressure. These findings demonstrate a simple strategy to realize thermally switchable magnetic materials with chemically tunable transition temperatures. (Figure presented.)

U2 - 10.1038/s41557-023-01422-8

DO - 10.1038/s41557-023-01422-8

M3 - Journal article

C2 - 38374454

AN - SCOPUS:85185327042

JO - Nature Chemistry

JF - Nature Chemistry

SN - 1755-4330

ER -