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

在这个由化学部化学合成项目资助的项目中，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铈的化合物。铈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，反应性极强。该项目的目标是开发合成的铈化学，将用于了解铈配体多键的独特反应性。这类物质的反应性有望实现其他金属所没有的独特化学反应，有助于发现新的、潜在增值的化学物质，包括染料、药品和聚合物。新的铈（+4）配体多键配合物的发现扩展了稀土元素的基础化学。在反应性研究中发现的新的有机化合物产生了社会效益。结果通过面向包括少数民族学生在内的初中生和高中生的拓展项目进行交流。未被充分代表的群体，包括妇女和未被充分代表的少数民族本科生和研究生，将从该项目的支持中受益。本项目主要研究稀土金属-配体多键配合物，即Ce（IV）配合物的合成和反应性研究。获得铈的四价态的能力有望使活性氧、亚胺、膦和其他配合物的分离成为可能，并使它们的反应性研究成为可能。还合成了铀和钍的类似5f同系物，通过比较了解其反应性和键合模式。相关电子结构的研究是利用光谱学和密度泛函理论进行的。反应模式，通过小分子活化研究辨别，建立了独特的亲核/亲电特性。

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.