Unexpected Supremacy of Non‐Dysprosium Single‐Ion Magnets within a Series of Isomorphic Lanthanide Cyanocobaltate(III) Complexes

Abstract

Slow relaxation of magnetization has been studied for a series of stable isomorphic 3D‐polynuclear Ln‐Co complexes comprising hexadentate [Co(CN)6]3– linkers, namely {[Ln(H2O)2][Co(CN)6]·2H2O}n where Ln = Tb (1), Dy (2), Er (3) and Yb (4). While 1 and 4 behave as field‐induced single‐ion magnets (SIMs), compounds 2 and 3 undergo rapid demagnetization even under magnetic fields up to 5000 Oe. The effective anisotropic energy barrier of 4 was estimated as 63 K (5000 Oe) which, to the best of our knowledge, is the highest value among Yb‐based SIMs. The obtained data are discussed in scope of the configuration of the Ln environment, i.e. accounting its composition and geometry as well as mutual arrangement of chemically unequal donating centers. Thus, the studied series of complexes represents very rare case when SIM performance of non‐dysprosium complexes far surpasses that of isomorphic Dy derivative.

Slow magnetic relaxation of mononuclear complexes based on uncommon Kramers lanthanide ions CeIII, SmIII and YbIII

“…Yb III -SIMs are studied more widely. 20,22,23 As the shape of the electron density of the m J = ±7/2 state is prolate, equatorial LFs are appropriate for Yb III . For example, in the complex Na [YbL 4 (H 2 O)] (L = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic, U eff = 24.3 cm −1 ), negative charges of the ligands are on the equatorial plane and lead to an easy anisotropy axis along the axial direction.…”

“…12,14,15 SMM behaviours have been observed in complexes based on all tripositive Kramers lanthanide ions, including widely used Dy III and Er III , 4,9,[13][14][15] as well as the uncommon ions Ce III , [16][17][18] Nd III , Sm III (ref. 19) and Yb III , [20][21][22][23][24] and even Gd III (with an isotropic ground state in the isolated ion). 25,26 The ions Ce III , Sm III and Yb III are rarely used for the construction of SIMs due to their significantly lower J.…”

Alkoxy-Bridged Dicopper(II) Cores Meet Tetracyanonickelate Linkers: Structural, Magnetic, and Theoretical Investigation of Cu/Ni Coordination Polymers

“…Systemic research has been conducted on the coordination polymers driven by the [M­(CN) x ] (M = Fe, Co, Ni, Cu, or Pd; x = 4 or 6) linkers . In this context, cyanometalate anions including [Fe­(CN) 6 ] 3– , − [Co­(CN) 6 ] 3– , ,− [Ni­(CN) 4 ] 2– , − or [Pd­(CN) 4 ] 2– ,, are particularly interesting given their ability to connect to other metal centers through a different number of cyanide groups, producing magnetically attractive heterometallic systems. However, the use of square-planar building blocks such as tetracyano­nickellate­(II) anions in the design of heterometallic systems containing multidentate aminoalcohols as stabilizing ligands has been underexplored.…”

Emissive lanthanide dicyanoaurate coordination polymers with 2,2′-bipyridine dioxide antenna groups and their hydration states

“…The incorporation of lanthanides into coordination polymers is a strategy that has been used to design functional materials including luminescence thermometers, chemical sensors, upconversion materials, single-molecule magnets, and catalysts. [1][2][3][4][5][6][7][8][9][10] The similar size and chemistry of the 4f metals often allows for the synthesis of solid solutions; the properties of the material can thus be fine-tuned by controlling the lanthanide composition. 8 To that end, the lanthanides are often utilized for colour tuning due to their fixed emission colours.…”