Nature of the Magnetic Interaction in the (Cu2+, Ln3+) Pairs: An Empirical Approach Based on the Comparison Between Homologous (Cu2+, Ln3+) and (NiLS2+, Ln3+) Complexes

Abstract

The reaction of {2,2'-[1-methyl-1,2-propanediyl bis(nitrilomethylidyne]-di(6-methoxyphenolato)}copper-(ii) (LCu) or nickel(ii) (LNi) with Ln(NO 3 ) 3 in acetone led to strictly heterodinuclear [LCu(Me 2 CO)Ln-(NO 3 ) 3 ] and [LNi(Me 2 CO)Ln(NO 3 ) 3 ] complexes (with Ln all the lanthanides except prometheum; Ni in the low-spin state). Three complexes [(Cu 2 , Ce 3 ), (Cu 2 , Yb 3 ) and (Ni 2 , Dy 3 )] have been structurally characterized. They crystallize in the same monoclinic spacegroups P2 1 /c (no. 14) and are isomorphous. This relationship in conjunction with the diamagnetism of the Ni 2 ion allow an empirical evaluation of the effect of the crystal field on the magnetic properties as well as an approach towards the nature of the coupling between the copper(ii) and the lanthani-de(iii) ions in the [LCu(Me 2 CO)Ln-(NO 3 ) 3 ] complexes. The Cu ± Ln interaction is antiferromagnetic for Ln Ce, Nd, Sm, Tm, and Yb, and ferromagnetic for Ln Gd, Tb, Dy, Ho, and Er; however, the Cu ± Pr and the Cu ± Eu pairs are devoid of any significant interaction along with the Cu ± La and Cu ± Lu pairs, in accordance with the nonmagnetic nature of the ground state for these lanthanide ions.

Reduction and selective oxo group silylation of the uranyl dication

“…2) that are magnetically independent; the thermal variation of the product of molar magnetic susceptibility and temperature, M T, is dominated by the magnetic contribution from the Fe ions. In contrast, the magnetic behaviour for 5 (2 to 300 K) should only contain contributions from the U centre 27 ; it displays two distinct regions ( Supplementary Fig. 2) associated with the depopulation of excited crystal field states of the U(V) f 1 cation and is similar to that observed for the few known organometallic pentavalent uranium complexes 28,29 .…”

Application of the Hubbard Model to Cp*2Yb(bipy), a Model System for Strong Exchange Coupling in Lanthanide Systems

“…In this way, the information about the ligand field and unquenched orbital angular momentum of 3 needed for eqn 2 is obtained from its diamagnetic substitute, 3 + I -. 19,37 Using χ TIP and the g-values of 3 + I -, eqn 2 yields 2J = -0.11(2) eV or -920(180) cm -1 . This surprisingly large value is consistent with the large value predicted computationally.…”

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

“…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.…”