ic5b00649_si_007.cif (1.49 MB)

Copper Lanthanide Phosphonate Cages: Highly Symmetric {Cu3Ln9P6} and {Cu6Ln6P6} Clusters with C3v and D3h Symmetry

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posted on 06.07.2015, 00:00 by Eufemio Moreno Pineda, Christian Heesing, Floriana Tuna, Yan-Zhen Zheng, Eric J. L. McInnes, Jürgen Schnack, Richard E. P. Winpenny
Two families of copper lanthanide phosphonate clusters have been obtained through reaction of [Cu2(O2CtBu)4(HO2CtBu)2] and either Ln­(NO3)3·nH2O or [Ln2(O2CtBu)6(HO2CtBu)6] and tert-butylphosphonic acid or an amino-functionalized phosphonic acid. The clusters, with general formula [Cu­(MeCN)4]­[Cu3Ln93-OH)7(O3PtBu)6(O2CtBu)15] and [Cu6Ln63-OH)6(O3PC­(NH2)­Me2)6(O2CtBu)12], were structurally characterized through single crystal X-ray diffraction and possess highly symmetric metal cores with approximately C3v and D3h point symmetry, respectively. We have investigated the possible application of the isotropic analogues in magnetic cooling, where we were able to observe that up to around 70% of the theoretical magnetic entropy change is obtained. Simulation of the magnetic data shows antiferromagnetic coupling between the spin centers, which explains the magnetic entropy value observed.