CAS: Can the Ionic Character of 1st Row and the Covalency of 2nd and 3rd Row Transition Metals Converge?

摘要：美国国家科学基金会化学部的化学合成项目支持彼得·T·卡耐基教授的研究。康奈尔大学的沃尔赞斯基。该项目旨在培养金属中心化学领域的候选人。大多数商品（散装）和精细（药理学）化学品是利用催化剂合成的。这些催化剂通常是加速反应速率的过渡金属化合物。这些催化剂中的许多使用低丰度、有毒且昂贵的金属。该计划正在研究合成更便宜的催化剂，但它们必须通过有机材料（称为配体）进行修饰，以提供必要的化学反应性来取代当前工业中使用的催化剂。一个正在探索的一般解决方案是研究配位体，这些配位体有望使更便宜的金属更具通用性或适应性。另一种通用方法是合成金属系统，以支持真正的变革过程：制备能够进行多步化学反应的化合物。一个具体的应用目标是使用螺旋桨形分子合成复合物，这些分子破裂产生所谓的亚烷基配体。 亚烷基金属化合物的合成将对美国化学工业的先进制造业产生广泛的影响。康奈尔大学集团还支持5年级和高中学生的STEM教育。 STEM工作包括讲座材料和实践培训模块。 技术摘要：美国国家科学基金会化学部的化学合成项目支持Peter T.康奈尔大学的沃尔赞斯基。该项目旨在培养无机和有机金属化学领域的博士候选人。该研究确定了几种在商品（散装）和精细（药理学）化学品生产方面具有潜在变革性的反应。用于催化的典型过渡金属丰度低且价格昂贵，该工作提出用廉价的第一和第二排物质取代这些物质。显示氧化还原非无辜的各种配体平台，包括可逆的C-C键形成，被用来扩大几个第一行金属的氧化还原容量。其他3-配位螯合物也参与H-转移化学，以进一步扩大反应性的范围。 探索离子键与共价键是这项工作的基础。类似于转移氢化的转移HX和H2添加以及类似于加氢裂化的过程是早期金属系统的目标。特定的系统显示出串联CH活化与烯烃复分解结合的潜力，导致H2与CH 2的净交换，并且一个三齿配体具有与齐格勒-纳塔交替的聚合机制的潜力。独特的应变试剂被用作许多过渡金属的亚烷基发生剂，因为替代昂贵的Ru基烯烃复分解催化剂是重要的目标。能够适应具有挑战性和波动性的学术或工业市场的独立，多功能博士的生产是一个主要目标，并通过报告（CDVR）作为正式氧化态的教学替代品的电荷分布的进一步发展将继续进行测试。康奈尔大学的研究小组也正在准备一个基于经验的五年级推广计划，并正在为高中生制定一个相关的推广计划。这个奖项反映了NSF的法定使命，并被认为是值得支持的，通过使用基金会的智力价值和更广泛的影响审查标准进行评估。

General Public Abstract:The Chemical Synthesis Program of the Chemistry Division of the National Science Foundation supports the research of Professor Peter T. Wolczanski of Cornell University. The project seeks to train candidates in the fields of metal-centered chemistry. Most commodity (bulk) and fine (pharmacological) chemicals are synthesized utilizing catalysts. These catalysts are typically transition metal compounds that accelerate the rates of reaction. Many of these catalysts use metals that are in low abundance, toxic, and expensive. This program is studying the synthesis of cheaper catalysts, but they must be modified by organic materials -- termed ligands -- in order to provide the chemical reactivity necessary to replace the current generation of catalysts used in industry. One general solution being explored is the investigation of ligands that promise to render the cheaper metals more versatile or adaptable. Another general approach is to synthesize metal systems that will underpin truly transformative processes: the preparation of compounds that are capable of multistep chemical reactions. A specific application targets the synthesis of complexes using propellar-shaped molecules that rupture to give what are called alkylidene ligands. Synthesis of alkylidene-metal compounds would have broad implications for the advanced manufacturing within the U.S. chemical industry. The Cornell group is also supports STEM education of 5th grade and high school students. The STEM efforts include lecture materials and hands-on training modules. These activities are helping to strengthen the workforce available to support the US chemical industry.Technical Abstract:The Chemical Synthesis Program of the Chemistry Division of the National Science Foundation supports the research program of Professor Peter T. Wolczanski of Cornell University. The project seeks to train PhD candidates in the fields of inorganic and organometallic chemistry. The research identifies several reactions that are potentially transformative in regards to commodity (bulk) and fine (pharmacological) chemicals production. Typical transition metals used in catalysis are in low abundance and costly, and the work proposes to supplant these species with inexpensive 1st and 2nd row species. Various ligand platforms that display redox non-innocence, including a reversible C-C bond formation, are employed to expand the redox capacity of several first-row metals. Other 3- coordinate chelates are also involved in H-transfer chemistry to further expand the scope of reactivity. Exploration of ionic vs. covalent bonding is fundamental to the work. Transfer HX and H2 additions, akin to transfer hydrogenations, and processes like hydroformylation, are targeted with early metal systems. Specific systems show potential for tandem CH activation in conjunction with olefin metathesis, leading to a net exchange of H2 for CH2, and one tridentate ligand has the potential for an alternate polymerization mechanism to Ziegler-Natta. Unique strained reagents are employed as alkylidene generators for numerous transition metals, as replacing expensive Ru-based olefin metathesis catalysts is an important target. The production of independent, versatile PhDs capable of adapting to a challenging and fluctuating academic or industrial market is a major objective, and the further development of Charge Distribution Via Reporters (CDVR) as a pedagogical alternative to formal oxidation states will continue to be tested. The Cornell group is also preparing a general 5th grade outreach program for publication based on experience, and is developing a related outreach program for high school students.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.