We thoroughly compared spectroscopic and magnetic properties of mononuclear iron(III) and manganese(III) complexes with symmetric and nonsymmetrical salen ligands, in order to investigate the relation between spectroscopic properties and electronic structures. Magnetic susceptibility and dual-mode electron paramagnetic resonance data show the assignment of [FeIII(salen)(OTf)] and [MnIII(salen)(OTf)] as high-spin S = 5/2 and S = 2 electronic configurations, respectively, irrespective of the electron-donating properties and symmetry of the salen ligand. Further insights into electronic structures of central metal are obtained from 2H NMR spectra of selectively deuterated complexes, in which [FeIII(salen)(OTf)] and [MnIII(salen)(OTf)] exhibit well-resolved paramagnetic NMR signals of quite different shift patterns, due to the presence or absence of the unpaired electron in the dx2 - y2 orbital expected for S = 5/2 iron(III) or S = 2 manganese(III) centers.
我们深入比较了具有对称和非对称
沙林配体的单核
铁(III)和
锰(III)配合物的光谱和磁学性质,以研究光谱性质与电子结构之间的关系。磁感应强度和双模电子顺磁共振数据表明,[FeIII(salen)(OTf)]和[MnIII(salen)(OTf)]分别具有高自旋 S = 5/2 和 S = 2 电子构型,与沙仑
配体的电子供能特性和对称性无关。选择性氚化配合物的 2H NMR 光谱进一步揭示了中心
金属的电子结构,其中[FeIII(salen)(OTf)]和[MnIII(salen)(OTf)]由于 S = 5/2
铁(III)或 S = 2
锰(III)中心预期的 dx2 - y2 轨道中未配对电子的存在或缺失,显示出移位模式迥异的分辨良好的顺磁 NMR 信号。