Jurić Marijana, Androš Dubraja Lidija, Popović Jasminka, Molčanov Krešimir, Torić Filip, Pajić Damir, Lončarić Ivor
Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia.
Department of Physics, Faculty of Science, University of Zagreb, Bijenička cesta 32, 10000 Zagreb, Croatia.
Dalton Trans. 2018 Mar 28;47(12):4183-4190. doi: 10.1039/c7dt04724j. Epub 2018 Feb 26.
Three heterometallic oxo-bridged compounds, [Cr(phen)(μ-O)Nb(CO)]·2HO (1; phen = 1,10-phenanthroline), [Cr(terpy)(HO)(μ-O)Nb(CO)]·4HO (2; terpy = 2,2';6',2''-terpyridine) and [Cr(terpy)(CO)(HO)][Cr(terpy)(CO)(μ-O)Nb(CO)]·3HO (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 P422 and P2/n space groups, respectively, contain a square-shaped {Cr(μ-O)Nb} unit, while that of complex salt 3 (P1[combining macron] space group) consists of a mononuclear cation containing Cr and trinuclear anions in which two Cr ions are bridged by a -O-Nb-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 for 1, 2 and 3, respectively) and confirmed by DFT calculations, originates from two Cr ions with spin 3/2 interacting through diamagnetic -O-Nb-O- bridge(s).
通过构建模块法合成了三种异金属氧桥化合物，即[Cr(phen)(μ - O)Nb(CO)]·2H₂O (1；phen = 1,10 - 菲咯啉)、[Cr(terpy)(H₂O)(μ - O)Nb(CO)]·4H₂O (2；terpy = 2,2';6',2'' - 三联吡啶)和[Cr(terpy)(CO)(H₂O)][Cr(terpy)(CO)(μ - O)Nb(CO)]·3H₂O (3)，并通过红外光谱、单晶和粉末X射线衍射、磁化率测量以及密度泛函理论计算对其进行了表征。1和2的分子结构分别结晶于P422和P2/n空间群，包含一个方形的{Cr(μ - O)Nb}单元，而复盐3（P1̅空间群）的分子结构由一个含Cr的单核阳离子和三核阴离子组成，其中两个Cr离子由 - O - Nb - O - 片段桥连。除了在1 - 3中形成一维或三维超分子排列的氢键模式外，在2的晶体堆积中，由于富电子的羰基氧与严重缺电子的碳原子之间的静电吸引，在平行的草酸根部分之间发现了一种不寻常的分子间接触。通过磁化率测量（1、2和3的J分别为 - 13.51(2)、 - 8.41(1)和 - 7.44(4) cm⁻¹）确定并经密度泛函理论计算证实，在所有三种化合物中观察到的反铁磁耦合源于两个自旋为3/2的Cr离子通过抗磁性的 - O - Nb - O - 桥相互作用。
