Schneider David, Harmgarth Nicole, Edelmann Frank T, Anwander Reiner
Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.
Institut für Chemie, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106, Magdeburg, Germany.
Chemistry. 2017 Sep 7;23(50):12243-12252. doi: 10.1002/chem.201700743. Epub 2017 May 12.
A series of heteroleptic tris(cyclopentadienyl) Ce complexes has been isolated and crystallographically characterized, revealing the broad accessibility of such organocerium(IV) compounds. The oxidation of complexes Cp Ce(thf) and Cp' Ce(thf) (Cp =C H Me, Cp'=C H SiMe ), bearing monosubstituted electron-poor cyclopentadienyl ligands, with 0.5 equivalents of 1,4-benzoquinone or C Cl gave the cerium(IV) hydroquinolate complexes Cp Ce(OC H O)CeCp and Cp' Ce(OC H O)CeCp' , or the chloride complexes Cp CeCl and Cp' CeCl, respectively; the iodide complex Cp' CeI was obtained from the reaction of Cp' Ce(thf) with elemental iodine. The behavior of Cp' CeCl in salt metathesis protocols employing alkali metal amides or alkyl, alkoxide, and aryloxide reagents was investigated, which gave rise to the robust and isolable cerium(IV) alkoxide Cp' Ce(OtBu). Trivalent [Cp' CeCl] was synthesized by AlMe →Cl exchange utilizing Cp' Ce(AlMe ) and AlMe Cl. The reactivity of [Cp' CeCl] towards the oxidants Ph CCl, C Cl , 1,4-benzoquinone, and I has been assessed, and has provided useful information on Ce /Ce redox deactivation pathways. In addition to X-ray structure analysis, all the complexes were characterized by NMR, DRIFT (diffuse reflectance IR Fourier transform), and UV/Vis spectroscopy as well as elemental analysis. The tetravalent compounds were further analyzed for their magnetic susceptibility by using Evans' method.
一系列杂配三（环戊二烯基）铈配合物已被分离并通过晶体学表征，揭示了此类有机铈（IV）化合物的广泛可及性。带有单取代缺电子环戊二烯基配体的配合物CpCe(thf)和Cp'Ce(thf)（Cp = C5H4Me，Cp' = C5H4SiMe3）与0.5当量的1,4 - 苯醌或CCl4氧化，分别得到铈（IV）对苯二酚盐配合物CpCe(OC6H4O)CeCp和Cp'Ce(OC6H4O)CeCp'，或氯化物配合物CpCeCl和Cp'CeCl；碘化物配合物Cp'CeI是由Cp'Ce(thf)与单质碘反应得到的。研究了Cp'CeCl在使用碱金属酰胺或烷基、醇盐和芳氧基试剂的盐复分解反应中的行为，得到了稳定且可分离的铈（IV）醇盐Cp'Ce(OtBu)。利用Cp'Ce(AlMe3)和AlMe3Cl通过AlMe3→Cl交换合成了三价的[Cp'CeCl]。评估了[Cp'CeCl]对氧化剂Ph3CCl、CCl4、1,4 - 苯醌和I2的反应活性，并提供了关于CeIV/CeIII氧化还原失活途径的有用信息。除了X射线结构分析外，所有配合物还通过NMR、DRIFT（漫反射红外傅里叶变换）、UV/Vis光谱以及元素分析进行了表征。使用埃文斯方法对四价化合物的磁化率进行了进一步分析。
