Transition Metal - Main Group Multiple Bonding

在化学系化学合成（SYN）项目的支持下，加州大学伯克利分校的T. Don Tilley教授将研究结合过渡金属和硅的化合物的新结构和反应。这一领域的发现有望提供新的化合物和化学转化，加速硅基材料的新兴应用，包括硅聚合物、粘合剂、润滑剂和半导体。主要目标是研究一种鲜为人知的化合物，其特征是硅原子仅与金属中心结合。这些化合物有望展现出尚未被彻底探索的特性，但有望帮助改善工业过程。此外，该计划通过提供一个培养批判性思维和解决问题能力发展的研究环境，为研究生和本科生在科学领域的职业生涯做好准备。有一个重要的教育推广组成部分，包括与转学生一起工作，以方便他们进入伯克利项目。学生们将参加拓展项目，包括接待高中生和与当地小学合作，通过互动课程教授基本的科学原理。长期以来，在培养研究生方面有着良好的记录；该培训包括准备学生与具有挑战性的化学品和试剂的工作。在金属和硅之间形式上具有多重键的配合物，如硅烯配合物（LnM=SiRR'），由于其在诸如硅烯转移或硅氢化等催化过程中假定或确定的作用，多年来引起了相当大的兴趣。该项目的重点将集中于更好地理解与多键相关的化学性质，主要有三个目标：(1)扩大具有M=Si双键的金属硅炔配合物的知识基础；(2)探索一类新的化合物-具有M=Si=M核心的分子硅化物；(3)开发与金属元素多键的信息，周期性关系，涉及较重的14族元素锗，锡，和铅。一个中心目标将是建立控制含有金属连接硅原子的分子硅化物的形成和转化的原理。相比之下，固态金属硅化物在技术上具有巨大的重要性，它是与硅形成或断开键的催化剂，比如在由单质硅直接合成有机硅烷的过程中。尽管过渡金属硅化物在技术上具有重要意义，但人们对其反应机制知之甚少，这一知识差距使得设计利用硅化物作为合成中间体的工艺变得困难。分子硅化物应适于硅化合物均相转化的机理研究和发展。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Chemical Synthesis (SYN) program in the Division of Chemistry, Professor T. Don Tilley of the University of California, Berkeley will study new structures and reactions of chemical compounds that incorporate both a transition metal and silicon. Discoveries in this area are expected to provide new compounds and chemical transformations that accelerate emerging applications of silicon-based materials, which include silicone polymers, adhesives, lubricants, and semiconductors. A primary objective is the study of a little understood type of chemical compound that features silicon atoms bonded only to metal centers. Such compounds are expected to exhibit properties that have yet to be thoroughly explored, but promise to aid the improvement of industrial processes. In addition, this program prepares graduate and undergraduate students for careers in science by providing a research environment that fosters critical thinking and problem-solving skill development. There is an important educational-outreach component that include work with transfer students to ease their entry into the Berkeley program. Students will participate in outreach programs that include hosting high school students and engaging with local elementary schools to teach basic scientific principles through interactive lessons. There is a long standing strong record of training of research students; this training includes preparing students to work with challenging chemicals and reagents.Complexes that formally possess a multiple bond between a metal and silicon, such as silylene complexes (LnM=SiRR'), have attracted considerable interest over the years, for their assumed or established role in catalytic processes such as silylene-transfer or hydrosilylation. The focus of this project will center on development of a better understanding of chemical properties associated with multiple bonding, with three primary aims designed to (1) expand the knowledge base for metal silylene complexes formally possessing M=Si double bonds, (2) explore a new class of compounds – molecular silicide complexes with M=Si=M cores, and (3) develop informative, periodic relationships to metal-element multiple bonds involving the heavier group 14 elements germanium, tin, and lead. A central objective will be establishing principles that govern formation and transformations of the molecular silicides, containing metal-ligated silicon atoms. For comparison, solid-state metal silicides are of immense technological importance as catalysts that make and break bonds to silicon, as in the direct process for the synthesis of organosilanes from elemental silicon. Despite the technological importance of transition-metal silicides, little is known about their reaction mechanisms and this knowledge gap makes it difficult to design processes that utilize silicides as synthetic intermediates. Molecular silicides should be amenable to mechanistic investigation and development of homogeneous transformations of silicon compounds.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.