Synthesis and Reactivity of Metallaradicals

在无机化学、生物无机化学和有机金属化学项目的资助下，西奥波德教授将继续他对烷基铬络合物化学的研究。在这一授权期内，重点将放在Cp*Cr(III)、Cp*Cr(II)和Cp*Cr-氧代烷基化合物上，以及一些新的Cp*Cr-oxo-M簇合物(Cp*是五甲基环戊二烯基团)。已经发现了处于正式IV、V和VI氧化态的Cp*Cr-氧代烷基络合物的例子。虽然这项研究的目标之一是合成和表征上述化合物的新实例，但工作的主要目的是确定这些化合物的反应模式。特别令人感兴趣的是它们作为新型聚合催化剂的活性，以及作为已知的非均相氧化铬/烷基铝基工业烯烃聚合催化剂的模型。由于大多数要考虑的化合物都是顺磁性的，它们的表征必须依赖于元素分析、反应产物分析和适当结晶材料的X射线结构测定。这个项目将探索含有未配对电子的有机金属化合物的基本化学。因此，它们与绝大多数已知的有机金属化合物具有非常不同的性质。因为它们很难从结构上进行表征，所以这些新化合物的化学成分还不是很清楚。据认为，这可能与目前用于生产聚烯烃的工业催化剂有关，聚烯烃用于许多家用消费品。这项研究可能会带来更好的催化剂来生产这些材料。

With funding from the Inorganic, Bioinorganic and Organo- metallic Chemistry Program, Professor Theopold will continue his studies of chromium alkyl complex chemistry. In this grant period the focus will be on Cp*Cr(III), Cp*Cr(II) and Cp*Cr-oxo alkyl complexes, and on some novel Cp*Cr-oxo-M cluster compounds (Cp* is the pentamethylcyclopentadienyl group). Examples of Cp*Cr-oxo alkyl complexes in the formal IV, V and VI oxidation states have already been discovered. Although one objective of the research is the synthesis and structural characterization of new examples of the above compounds, the primary thrust of the work is to define the reactivity patterns of these classes of compounds. Of special interest is their activity as new polymerization catalysts and as models for the known heterogeneous chromium oxide/aluminum alkyl based industrial olefin polymerization catalysts. Because most of the compounds to be considered are paramagnetic, their characterization must rely on elemental analysis, reaction product analysis and x-ray structure determinations on suitably crystalline materials. %%% This project will explore the fundamental chemistry of organometallic compounds that contain unpaired electrons. As such, they have very different properties from the vast majority of known organometallic compounds. Because they are much harder to characterize with respect to structure, the chemistry of these novel compounds is not well known. It is believed that they may be related to current industrial catalysts that are used for production of polyolefins which are used in many household consumer products. This research may lead to even better catalysts for the production of these materials.