From a square core to square opening: structural diversity and magnetic properties of the oxo-bridged [CrIIINbV] complexes. Issue 12 (26th February 2018)

• Record Type: Journal Article
• Authors: Jurić, Marijana; Androš Dubraja, Lidija; Popović, Jasminka; Molčanov, Krešimir; Torić, Filip; Pajić, Damir; Lončarić, Ivor
• Is Part Of: Dalton transactions. Volume 47:Issue 12(2018)
• Page Start: 4183
• Page End: 4190
• Publication Date: 2018-02-26
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c7dt04724j
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Three oxo-bridged [Cr III Nb V ] compounds exhibit antiferromagnetic coupling between Cr III ions mediated through the diamagnetic –O–Nb V –O– bridge, as observed by magnetization measurements and DFT calculations. Abstract : Three heterometallic oxo-bridged compounds, [Cr2 (phen)4 (μ-O)4 Nb2 (C2 O4 )4 ]·2H2 O (1 ; phen = 1, 10-phenanthroline), [Cr2 (terpy)2 (H2 O)2 (μ-O)4 Nb2 (C2 O4 )4 ]·4H2 O (2 ; terpy = 2, 2′;6′, 2′′-terpyridine) and [Cr(terpy)(C2 O4 )(H2 O)][Cr2 (terpy)2 (C2 O4 )2 (μ-O)2 Nb(C2 O4 )2 ]·3H2 O (3 ), have been synthesized using a building block approach and characterized by IR spectroscopy, single-crystal and powder X-ray diffraction, magnetization measurements, and DFT calculations. The molecular structures of 1 and 2, crystallizing in P 42 21 2 and P 21 / n space groups, respectively, contain a square-shaped {CrIII2(μ-O)4 NbV2} unit, while that of complex salt 3 ( P 1̄ space group) consists of a mononuclear cation containing Cr III and trinuclear anions in which two Cr III ions are bridged by a –O–Nb V –O– fragment. Besides hydrogen-bonding patterns resulting in a 1D- or 3D-supramolecular arrangement in 1–3, an unusual intermolecular contact has been noticed between parallel oxalate moieties occurring due to the electrostatic attraction of electron-rich carbonyl oxygen and severely electron-depleted carbon atoms in the crystal packing of 2 . The antiferromagnetic coupling observed in all three compounds, determined from magnetization measurements ( J = −13.51(2), −8.41(1) and −7.44(4) cm −1 for 1, 2 and 3, respectively) and confirmed by DFT calculations, originates from two Cr III ions with spin 3/2 interacting through diamagnetic –O–Nb V –O– bridge(s).