Early Transition Metal Complexes with Polydentate Polyanionic Ligands as Olefin Polymerization Catalysts

该项目由无机、生物无机和有机金属化学项目支持，将支持佛罗里达大学J. Boncella教授继续研究过渡金属聚合催化剂。研究多齿、聚阴离子配体的过渡金属配合物，目的如下：1)继续发展烯烃复分解聚合和解聚催化剂，重点是最近开发的一种基于钨的N，N'-双（三甲基硅基）-邻苯二胺催化剂的作用机理；2)用这种钨化合物观察到的C-H键活化反应的可能应用；3)在同一金属中心进行复分解聚合和Zeigler-Natta型聚合的催化剂的发展。4)在吡啶配体的基础上合成了一类新的聚阴离子配体，包括一些比连接原子携带更多电荷的配体。这类新的配体有望合成高氧化态的早期过渡金属配合物，这些配合物具有异常低的配位数，并且可能具有增强的反应活性。过渡金属催化剂的性质主要取决于附着在活性金属中心的基团（配体）的类型和数量。本项目涉及几种新型催化剂的合成和研究。本研究的目标之一是：1)开发新型的聚合催化剂，这些催化剂具有热稳定性，可以聚合目前由于催化剂不稳定而无法聚合的单体；2)开发双功能催化剂，可以用于通过不同机理进行聚合的两种单体的共聚合。

This project supported by the Inorganic, Bioinorganic, and Organometallic Chemistry Program will support the continuation of studies of transition metal polymerization catalysts by Professor J. Boncella of the University of Florida. Studies of transition metal complexes of polydentate, polyanionic ligands will be undertaken with the following objectives: 1) continued development of catalysts for olefin metathesis polymerization and depolymerization with emphasis on the mechanism of action of a recently developed tungsten-based catalyst of N,N'-bis(trimethylsilyl)-o-phenylenediamide, 2) possible applications for C-H bond activation reactions that are observed with this tungsten compound, 3) development of catalysts that will perform both metathesis polymerization and Zeigler-Natta type polymerizations at the same metal center, and 4) the synthesis of a new class of polyanionic ligands based upon the pyrrolide ligand, including some that carry more charge than ligating atoms. This new class of ligands is expected to lead to the synthesis of high oxidation state early transition metal complexes that have unusually low coordination numbers and which may have enhanced reactivity. The properties of transition metal catalysts are critically dependent upon the type and number of groups (ligands) that are attached to the active metal center. This project involves the synthesis and study of several new catalysts. Among objectives of this research are 1) the development of new types of polymerization catalysts that are thermally robust and allow for the polymerization of monomers that cannot currently be polymerized because of catalyst instability, and 2) the development of dual function catalysts that can be used to co-polymerize two monomers that undergo polymerization by different mechanisms.