TY - JOUR
T1 - X-ray magnetic circular dichroism (XMCD) study of a methoxide-bridged DyIII-CrIII cluster obtained by fluoride abstraction from cis-[CrIIIF2(phen)2]+
AU - Dreiser, Jan
AU - Pedersen, Kasper Steen
AU - Birk, Torben
AU - Schau-Magnussen, Magnus
AU - Piamonteze, Cinthia
AU - Rusponi, Stefano
AU - Weyhermüller, Thomas
AU - Brune, Harald
AU - Nolting, Frithjof
AU - Bendix, Jesper
PY - 2012/8/2
Y1 - 2012/8/2
N2 - An isostructural series of dinuclear chromium(III)-lanthanide(III) clusters is formed by fluoride abstraction of cis-[CrF2(phen) 2]+ by Ln3+ resulting in LnF3 and methoxide-bridged Cr-Ln clusters (Ln = Nd (1), Tb (2), Dy (3)) of formula [CrIII(phen)2(μ-MeO)2Ln(NO3) 4]•xMeOH (x = 2-2.73). In contrast to fluoride, methoxide bridges in a nonlinear fashion, which facilitates chelation. For 3, X-ray magnetic circular dichroism (XMCD) provides element-specific magnetization curves that are compared to cluster magnetization and susceptibility data acquired by SQUID magnetometry. The combination of XMCD and SQUID is able to resolve very small magnetic coupling values and reveals a weak Cr III-DyIII coupling of j = -0.04(3) cm-1. The DyIII ion has a ground-state Kramers doublet of mJ = ±13/2, and the first excited doublet is found to be mJ = ±11/2 at an energy of δ = 57(21) cm-1. The Cr III ion exhibits a uniaxial anisotropy of DCr = -1.7(1.0) cm-1. Further, we observe that a weak anisotropic coupling of dipolar origin is sufficient to model the data, suggesting that methoxide bridges do not play a significant role in the magnetic coupling for the present systems.
AB - An isostructural series of dinuclear chromium(III)-lanthanide(III) clusters is formed by fluoride abstraction of cis-[CrF2(phen) 2]+ by Ln3+ resulting in LnF3 and methoxide-bridged Cr-Ln clusters (Ln = Nd (1), Tb (2), Dy (3)) of formula [CrIII(phen)2(μ-MeO)2Ln(NO3) 4]•xMeOH (x = 2-2.73). In contrast to fluoride, methoxide bridges in a nonlinear fashion, which facilitates chelation. For 3, X-ray magnetic circular dichroism (XMCD) provides element-specific magnetization curves that are compared to cluster magnetization and susceptibility data acquired by SQUID magnetometry. The combination of XMCD and SQUID is able to resolve very small magnetic coupling values and reveals a weak Cr III-DyIII coupling of j = -0.04(3) cm-1. The DyIII ion has a ground-state Kramers doublet of mJ = ±13/2, and the first excited doublet is found to be mJ = ±11/2 at an energy of δ = 57(21) cm-1. The Cr III ion exhibits a uniaxial anisotropy of DCr = -1.7(1.0) cm-1. Further, we observe that a weak anisotropic coupling of dipolar origin is sufficient to model the data, suggesting that methoxide bridges do not play a significant role in the magnetic coupling for the present systems.
U2 - 10.1021/jp303512a
DO - 10.1021/jp303512a
M3 - Journal article
C2 - 22788870
SN - 1089-5639
VL - 116
SP - 7842
EP - 7847
JO - Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory
JF - Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory
IS - 30
ER -