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Abstract：
Two trinuclear oxo-centred iron(III) coordination compounds of monensic and salinomycinic acids (HL) were synthesized and their spectral properties were studied using physicochemical/thermal methods (FT-IR, TG-DTA, TG-MS, EPR, Mössbauer spectroscopy, powder XRD) and elemental analysis. The data suggested the formation of [Fe3(µ3-O)L3(OH)4] and the probable complex structures were modelled using the DFT method. The computed spectral parameters of the optimized constructs were compared to the experimentally measured ones. In each complex, three metal centres were joined together at the axial position by a μ3-O unit to form a {Fe3O}7+ core. The antibiotics monoanions served as bidentate ligands through the carboxylate and hydroxyl groups located at the termini. The carboxylate moieties played a dual role bridging each two metal centres. Hydroxide anions secured the overall neutral character of the coordination species. Mössbauer spectra displayed asymmetric quadrupole doublets that were consistent with the existence of two types of high-spin iron(III) sites with different environments-two Fe[O5] and one Fe[O6] centres. The solid-state EPR studies confirmed the +3 oxidation state of iron with a total spin St = 5/2 per trinuclear cluster. The studied complexes are the first iron(III) coordination compounds of monensin and salinomycin reported so far.
摘要：
合成了两个三核氧氧为中心的单烯酸和盐霉素（HL）的铁（III）配位化合物，并使用物理化学/热方法研究了其光谱性质（FT-IR，TG-DTA,TG-MS,EPR,穆斯堡尔谱学,粉末XRD)和元素分析。数据表明[Fe3（µ3-O）L3（OH）4]的形成，并且使用DFT方法对可能的复杂结构进行了建模。将优化的构建体的计算光谱参数与实验测量的光谱参数进行比较。在每个复合体中，三个金属中心在轴向位置通过μ3-O单元连接在一起以形成{Fe3O}7+芯。抗生素单阴离子通过位于末端的羧酸根和羟基充当二齿配体。羧酸盐部分起到桥接每两个金属中心的双重作用。氢氧阴离子确保了配位物种的整体中性特性。Mössbauer光谱显示出不对称的四极双峰，这与具有不同环境的两种类型的高自旋铁（III）位点的存在一致-两个Fe[O5]和一个Fe[O6]中心。固态EPR研究证实了铁的3氧化态，每个三核簇的总自旋St=5/2。所研究的络合物是迄今为止报道的莫能菌素和盐霉素的第一个铁（III）配位化合物。
