The power of lanthanides: same composition, but different lanthanides leading to different interesting materials properties, from magnetocalorics to molecular magnets and phosphors

TY - JOUR

T1 - The power of lanthanides

T2 - same composition, but different lanthanides leading to different interesting materials properties, from magnetocalorics to molecular magnets and phosphors

AU - Wilk-Kozubek, Magdalena

AU - Mudryk, Yaroslav

AU - Prodius, Denis

AU - Dolotko, Oleksandr

AU - Ahmed, Sheikh J.

AU - Overgaard, Jacob

AU - Smetana, Volodymyr

AU - Mudring, Anja Verena

PY - 2025/12/1

Y1 - 2025/12/1

N2 - Commonly accepted design concepts for ionic liquids (ILs) state that the constituting ions must be large and carry low, well-dispersed charges. A series of ILs based of pentadeca charged ILs with pentanuclear linear {Ln5} units ([Ln5(C2H5-C3H3N2-CH2COO)16(H2O)8](Tf2N)15 (C3H3N2 = imidazolium moiety, Tf2N = bis(trifluoromethanesulfonyl)amide) with Ln = Er, Ho, Tm) demonstrates that these criteria are not absolute. Highly charged ions can also support IL formation, provided they are sufficiently large. Expanding the series of these unconventional, record pentadeca charged with new lanthanide representatives, led to the discovery of additional unprecedented properties for ILs: The Gd compound exhibits a strong magnetocaloric effect (MCE) in the liquid state with a maximum magnetic entropy change of −ΔSM = −11 J⋅kg−1⋅K−1 at 2 K for Δμ0H = 7 T. Albeit the Dy representative shows slow magnetic relaxation, the relaxation times are not favorable for practical application as a molecular magnet. Lastly, for both the Gd and the Y compound, phosphorescence in the seconds time scale is observed, which is, to the best of our knowledge, the longest ever reported for an IL.

AB - Commonly accepted design concepts for ionic liquids (ILs) state that the constituting ions must be large and carry low, well-dispersed charges. A series of ILs based of pentadeca charged ILs with pentanuclear linear {Ln5} units ([Ln5(C2H5-C3H3N2-CH2COO)16(H2O)8](Tf2N)15 (C3H3N2 = imidazolium moiety, Tf2N = bis(trifluoromethanesulfonyl)amide) with Ln = Er, Ho, Tm) demonstrates that these criteria are not absolute. Highly charged ions can also support IL formation, provided they are sufficiently large. Expanding the series of these unconventional, record pentadeca charged with new lanthanide representatives, led to the discovery of additional unprecedented properties for ILs: The Gd compound exhibits a strong magnetocaloric effect (MCE) in the liquid state with a maximum magnetic entropy change of −ΔSM = −11 J⋅kg−1⋅K−1 at 2 K for Δμ0H = 7 T. Albeit the Dy representative shows slow magnetic relaxation, the relaxation times are not favorable for practical application as a molecular magnet. Lastly, for both the Gd and the Y compound, phosphorescence in the seconds time scale is observed, which is, to the best of our knowledge, the longest ever reported for an IL.

KW - Ionic liquids

KW - Lanthanides

KW - Luminescence

KW - Magnetism

KW - Magnetocalorics

KW - Molecular magnets

KW - Phosphorescence

UR - https://www.scopus.com/pages/publications/105017418240

U2 - 10.1016/j.poly.2025.117798

DO - 10.1016/j.poly.2025.117798

M3 - Journal article

AN - SCOPUS:105017418240

SN - 0277-5387

VL - 282

JO - Polyhedron

JF - Polyhedron

M1 - 117798

ER -