Diminishing the Amount of Transition Metal ATRP Catalyst Through the Use of Reducing Agents

这项建议的主要目的是充分了解ATRP(原子转移自由基聚合)是如何在使用非常少量的过渡金属催化剂的体系中进行的，并确定如何设计一个最佳的催化/氧化还原体系来减少催化剂的用量，同时保持足够的聚合控制。我们建议探索各种金属、配体和还原剂的结构-反应性效应，以及介质和温度对以ppm的铜催化剂进行的新的ATRP体系的影响。主要的智力挑战是准确地确定所涉及的所有元素反应的动力学和热力学参数，并将关键试剂的结构与它们的反应性联系起来。我们将测量最活跃的ATRP催化剂的平衡常数、稳定常数、氧化还原电位和卤化物亲和力。我们还将研究具有新的多齿配体和带电配体的配合物的行为。我们将测量看似合理的歧化程度，并量化还原剂与催化剂的相互作用。我们还将测定所有相关反应的速率常数。获得的数据将被用来构建一个全面的模型，该模型可以在各种条件下应用，适用于大范围的单体，并用于更好的建筑控制。这也将有助于扩大可聚合单体的范围，减少过渡金属催化剂的浓度。所产生的知识将有助于推进有机原子转移反应，并将为更良性的ATRP过程提供工业指导。我们预计，来自这一提案的研究将通过培养研究生和本科生以及博士后研究员产生广泛的影响。信息将以及时出版物的形式在互联网上传播，并通过在(国际)国家研讨会和卡内基梅隆大学的外联计划上的演讲来传播。我们继续与大约15家公司开展受控自由基聚合联盟，这些公司将受益于NSF支持的活动产生的知识。我们预计，由美国国家科学基金会支持的拟议研究不仅将影响合成聚合物化学，还将影响材料科学，并可能导致一些具有商业价值的材料的开发。

The main objective of this proposal is to fully comprehend how ATRP (Atom Transfer Radical Polymerization) proceeds in systems with very small amounts of transition metal catalyst, and also to determine how to design an optimal catalytic/redox system to diminish the amount of catalyst while retaining sufficient polymerization control. We propose to explore structure-reactivity effects of various metals, ligands, and reducing agents, as well as the effect of medium and temperature on new ATRP systems that proceed with ppm amounts of copper catalyst. The main intellectual challenge is to precisely determine kinetic and thermodynamic parameters for all elementary reactions involved and to correlate the structure of the key reagents with their reactivity. We will measure equilibrium constants, stability constants, redox potentials and halide affinities for the most active ATRP catalysts. We will also study the behavior of complexes with new multidentate ligands and with charged ligands. We will measure the extent of a plausible disproportionation and quantify interactions of reducing agents with catalysts. We will also determine rate constants of all relevant reactions. The obtained data will be used to construct a comprehensive model that can be applied under various conditions, for a large range of monomers, and for better architectural control. This will also help to expand range of polymerizable monomers and diminish concentration of transition metal catalysts. The generated knowledge will help advance organic atom transfer reactions and will also provide leads to industry for more benign ATRP processes.We anticipate that the research from this proposal will have a broad impact by educating graduate and undergraduate students as well as postdoctoral fellows. Information will be disseminated in the form of timely publications, on the internet, and through presentations at (inter)national symposia and the outreach program at Carnegie Mellon University. We continue the Controlled Radical Polymerization Consortium with ~ 15 companies that will benefit from the knowledge generated by the NSF supported activities. We expect that the proposed research to be supported by the NSF will impact not only synthetic polymer chemistry but also materials science and may lead to the development of some commercially valuable materials.