Synthesis, Characterization and Reactivity Studies of Cerium Metal-Ligand Multiple Bonds

在这个由化学系化学合成计划资助的项目中，宾夕法尼亚大学的Eric Schelter教授和他的研究小组正在制备元素Ce3+的化合物。Ce是稀土元素中的一员，具有独特的性质。稀土化合物形成双键和三键，具有极强的活性。这个项目的目标是开发合成的Ce3+化学，它将用于理解Ce-配体多键的独特反应活性。这些物种的反应性预计将使人们能够在没有其他金属的情况下发现独特的化学物质，有助于发现新的、具有潜在附加值的化学品，包括染料、药物和聚合物。含Ce(4)-配体多键的新配合物的发现拓展了稀土元素的基础化学。社会效益是从反应性研究中确定的新有机化合物中积累的。结果通过面向包括少数族裔学生在内的年级和高中生的外展计划进行传达。代表不足的群体，包括妇女和代表不足的少数族裔本科生和研究生受益于对该项目的支持。本项目致力于稀土金属-配体多键配合物的合成和反应性研究，即Ce(IV)的配合物。Ce达到四价态的能力有望使反应性氧-、亚胺-、膦和其他络合物能够分离，并能够研究它们的反应性。还合成了相关的5f同系物铀和钍的类似化合物，通过比较了解其反应性和成键方式。结合光谱学和密度泛函理论对相关电子结构进行了研究。通过小分子活化研究识别的反应模式建立了独特的亲核/亲电特征。

In this project funded by the Chemical Synthesis program of the Chemistry Division Professor Eric Schelter and his research group at the University of Pennsylvania is preparing compounds of the element cerium. Cerium is a member of the rare earth elements, which possess distinctive properties. Compounds of rare earths form double and triple bonds that are extremely reactive. The goal of this project is to develop synthetic cerium chemistry that will be used to understand the unique reactivity of cerium-ligand multiple bonds. The reactivity of such species is expected to enable unique chemistry found with no other metals, contributing to the discovery of new, potentially value-added chemicals including dyes, pharmaceuticals and polymers. The discovery of new complexes bearing cerium(+4)-ligand multiple bonds expands fundamental chemistry of the rare earth elements. Societal benefits are accrued from new organic compounds identified in reactivity studies. Results are communicated through outreach programs for grade- and high school students including minority students. Underrepresented groups including women and underrepresented minority undergraduates and graduate students benefit from support of the project. This project focuses on synthesis and reactivity studies of complexes bearing rare earth metal-ligand multiple bonds, namely those of Ce(IV). The ability to attain the tetravalent state for cerium is expected to enable isolation of reactive oxo-, imido-, phosphinidine and other complexes and enable studies of their reactivity. Analogous compounds of the related 5f congeners uranium and thorium are also synthesized to understand the reactivity and bonding patterns through comparison. Studies of the associated electronic structures are performed using spectroscopy together with density functional theory. Reactivity patterns, discerned through small molecule activation studies, are established the unique nucleophilic/electrophilic characteristics.