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教授将研究同时包含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，包括有机硅聚合物、粘合剂、润滑剂和半导体。一个主要目标是研究一种鲜为人知的化合物类型，其特征是硅原子只与金属中心键合。这类化合物有望展示出尚未彻底探索的特性，但有望帮助改进工业工艺。此外，该计划通过提供促进批判性思维和解决问题技能发展的研究环境，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部分，其中包括与转学学生合作，使他们更容易进入伯克利项目。学生将参加外展计划，包括招待高中生，并与当地小学接触，通过互动课程教授基本科学原理。长期以来，对研究生的培训有很好的记录；这种培训包括让学生准备好使用具有挑战性的化学品和试剂。形式上在金属和硅之间具有多个键的络合物，如硅烯络合物(LNM=SIRR‘)，多年来引起了人们的极大兴趣，因为它们在硅烯转移或硅氢化等催化过程中承担或确立了作用。该项目的重点将集中在更好地了解与多键相关的化学性质，主要目的有三个，旨在(1)扩大正式具有M=Si双键的金属硅烯络合物的知识库，(2)探索一类新的化合物-具有M=Si=M核的分子硅化物络合物，以及(3)发展与较重的14族元素锗、锡和铅的金属-元素多键的信息、周期关系。一个中心目标将是建立管理分子硅化物的形成和转化的原则，分子硅化物包含金属连接的硅原子。相比之下，固态金属硅化物作为与硅建立和断开键的催化剂具有巨大的技术重要性，就像从元素硅合成有机硅烷的直接过程一样。尽管过渡金属硅化物在技术上很重要，但人们对其反应机理知之甚少，这种知识差距使设计利用硅化物作为合成中间体的工艺变得困难。分子硅化物应服从硅化合物均质转化的机械研究和开发。该奖项反映了NSF的法定使命，并已通过使用基金会的智力优势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.