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From square core to square opening: Structural diversity and magnetic properties of the oxo-bridged [CrIIINbV] complexes

Abstract

Three heterometallic oxo-bridged compounds [Cr2(phen)4(μ-O)4Nb2(C2O4)4]·2H2O (1; phen = 1,10-phenanthroline), [Cr2(terpy)2(H2O)2(μ-O)4Nb2(C2O4)4]·4H2O (2; terpy = 2,2';6',2"-terpyridine) and [Cr(terpy)(C2O4)(H2O)][Cr2(terpy)2(C2O4)2(μ-O)2Nb(C2O4)2]·3H2O (3) have been synthesized using a building block approach and characterized by IR spectroscopy, single-crystal and powder X-ray diffraction, magnetization measurement and DFT calculations. The molecular structures of 1 and 2, crystallizing in P42212 and P21/n space groups respectively, contain square-shaped {CrIII2(μ-O)4NbV} unit, while that of complex salt 3 (P1 @#x0305; space group) consist of a mononuclear cation containing CrIII and trinuclear anion in which two CrIII ions are bridged by –O–NbV–O– fragment. Beside hydrogen-bonding patterns resulting in 1D- or 3D-supramolecular arrangement in 1–3, an unusual intermolecular contact has been noticed between parallel oxalate moieties occurring due to electrostatic attraction of electron-rich carbonyl oxygen and severely electron-depleted carbon atom in the crystal packing of 2. The antiferromagnetic coupling observed in all three compounds, determined from magnetization measurements (J = –13.51, –8.41 and –7.44 cm–1 for 1, 2 and 3, respectively) and confirmed by DFT calculations, originates from two CrIII ions with spin 3/2 interacting through diamagnetic –O–NbV–O– bridge(s).

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Publication details

The article was received on 14 Dec 2017, accepted on 05 Feb 2018 and first published on 06 Feb 2018


Article type: Paper
DOI: 10.1039/C7DT04724J
Citation: Dalton Trans., 2018, Accepted Manuscript
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    From square core to square opening: Structural diversity and magnetic properties of the oxo-bridged [CrIIINbV] complexes

    M. Juric, L. Androš Dubraja, J. Popović, K. Molcanov, F. Torić, D. Pajić and I. Lončarić, Dalton Trans., 2018, Accepted Manuscript , DOI: 10.1039/C7DT04724J

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