Systematic Investigations of the Nature of the Coupling between a Ln(III) Ion (Ln = Ce(III) to Dy(III)) and Its Aminoxyl Radical Ligands. Structural and Magnetic Characteristics of a Series of {Ln(organic radical)₂} Compounds and the Related {Ln(Nitrone)₂} Derivatives  [J. Am. Chem. Soc. 2000, 122, 3413−3421].

Abstract

We noted in the experimental section that one of the reported crystal structures, {Pr(Nitrone) 2 (NO 3 ) 3 }, may be better described in the noncentrosymmetric space group P1 than in the centrosymmetric space group P1 h; this choice was based on better classical quality criterions in the former. Nevertheless, following discussions with careful readers we acknowledge and from consideration based on atomic displacement parameters we believe that this crystal structure is more likely to be centrosymmetric. However, nothing discussed in the article is modified by such a correction.

Quantifying Exchange Coupling in f-Ion Pairs Using the Diamagnetic Substitution Method

“…[10][11][12][13] In addition, a large number of studies have examined the coupling between f-ions and adjacent paramagnetic transition metals or organic radicals. 1,[14][15][16][17][18][19][20][21][22][23][24][25][26][27] Two factors make it challenging to quantify f-electron coupling. First, the magnetic moments of f-ions, except for f 7 -systems, are temperature dependent and highly anisotropic due to a combination of strong spin-orbit coupling and weak crystal fields.…”

“…15,16,33 The magnetically isolated analog has a very similar crystal field to the original f-ion pair but lacks the complicating effect of the coupling between the fions. The susceptibility of the magnetically isolated analog may be subtracted from the susceptibility of the coupled system to determine whether the coupling is ferromagnetic or antiferromagnetic.…”

Coupling of the 4f Electrons in Lanthanide Molecules

“…The closest contact in the ion-pair is between C(28) and C(36); it is 3.243 (4) Å. The closest contact distance in the ion-pair is 3.507(7) Å between C(11) and C (24). The N1-C11-C11-N1 torsion angle is 1.3(1)°.…”

Exchange interaction in binuclear complexes with rare-earth and copper ions: A many-body model study

“…Mononuclear complexes of Gd 3+ are already known. Systems with ground state spin higher than 7 2 can be built up with multinuclear complexes involving Gd 3+ and other rare-earth or transition metal ions. Studies of such heteropolymetallic compounds have also been of great interest in modeling metaloenzymes and in understanding their magnetic properties [2].…”

“…The interaction between Cu(II)-Ln(III) is ferromagnetic for Gd(III) and other rare-earth ions with greater than half-filled 4 f shell such as Dy(III) and Er(III). Below half filling, this interaction is antiferromagnetic and leads to low-spin ground state for systems such as Cu(II)-Ce(III) and Cu(II)-Eu(III) [7]. The situation remains the same when the Cu(II) is replaced by organic ligands like nitronyl nitroxide triazole which are essentially spin-1/2 carriers.…”