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Dynamic Magnetic Materials Based on the Cationic Coordination Polymer [Cu(btix)2]n2n+ [btix = 1,4-Bis(triazol-1-ylmethyl)benzene]: Tuning the Structural and Magnetic Properties through Anion Exchange
journal contribution
posted on 2012-12-03, 00:00 authored by Eugenio Coronado, Mónica Giménez-Marqués, Carlos
J. Gómez-García, Guillermo Mínguez EspallargasA three-dimensional coordination polymer, [Cu(btix)2(BF4)2]n [btix
= 1,4-bis(triazol-1-ylmethyl)benzene], with antiferromagnetic interactions
occurring via the organic ligand, has been prepared and characterized.
It has been shown to permit the exchange of anionic species in the
crystalline network with modification of the magnetic properties.
Coordinated BF4– can be reversibly exchanged
by different anions with (NO3– and Cl–) or without (PF6– and
ClO4–) dynamic response of the organic
ligand, which acts as the only linker between the metal centers. Interestingly,
an irreversible exchange occurs with N3– anions to generate a new coordination polymer, [Cu(btix)(N3)2]n, whose structure has
been determined ab initio by powder X-ray diffraction, revealing a
totally different connectivity between the CuII centers.
These structural transformations are accompanied by a change of the
magnetic properties, which have been detected by electron paramagnetic
resonance and magnetic susceptibility measurements.