Development of a Hydride Donor Scale

无机，生物无机和有机化学计划的这一奖项支持科罗拉多大学博尔德分校化学和生物化学系的玛丽·拉科夫斯基·杜波依斯教授和科罗拉多州戈尔登国家可再生能源实验室的丹尼尔·杜波依斯博士对氢化物供体规模规模发展的研究。一系列现有的和新合成的等电子和同构的过渡金属双膦配合物将被用来确定它们的氢化物供体强度作为测量的异裂键离解自由能。酸度和均裂键解离自由能也将作为用于获得该底物和溶剂独立供体强度标度的热力学循环的一部分来确定。在建立该标度后，将使具有一系列供体能力的许多化合物与有机底物反应，以检查这些供体值与氢化物反应性（“供体性”）之间的关系。该热力学标度将被扩展以获得甲基阳离子、阴离子和自由基的转移的相对值，本研究的目标是开发金属氢化物化合物将氢转移到基底的能力的定量标度，并将这些数字与它们的反应性相关联。有机化合物的催化氢化具有重要的工业意义，金属氢化物通常是这些反应中的中间体。这项研究的结果将支持更有效的催化过程的设计，在这项工作中制备的一些金属氧化物本身可能具有作为反应物或催化材料的价值。参与该项目的学生将学习合成和仪器方法的广泛技能，并在将基础化学与工业催化联系起来的努力中获得经验。

This award in the Inorganic, Bioinorganic and Organometallic Chemistry program supports research on the development of a hydride donor scale scale by Professor Mary Rakowski DuBois of the Department of Chemistry and Biochemistry at the University of Colorado-Boulder and Dr. Daniel DuBois at the National Renewable Energy Laboratory, Golden, Colorado. A series of both existing and newly-synthesized isoelectronic and isostructural transition metal hydridse diphosphine complexes will be employed to determine their hydride donor strength as measured by the heterolytic bond dissociation free energies. The acidities and homolytic bond dissociation free energies will also be determined as part of the thermodynamic cycles used to obtain this substrate and solvent-independent donor strength scale. After this scale is established, a number of compounds with a range of donor abilities will be reacted with organic substrates to examine the relationship between these donor values and hydride reactivity ("donicity"). This thermodynamic scale will be extended to obtain relative values for the transfer of the methyl cation, anion and radical.The goal of this research is to develop a quantitative scale for the ability of metal hydride compounds to transfer hydrogen to a substrate, and to relate these numbers to their reactivity. Catalytic hydogenation of organic compounds is of great industrial importance, and metal hydrides are often intermediates in these reactions. The results of this study will support the design of more efficient catalytic processes, and some of the metal hydrides prepared in this work may themselves have value as reactant or catalytic materials. Students involved in the project will learn a breadth of skills in both synthesis and instrumental methods, and gain experience in an effort which links fundamental chemistry with industrial catalysis.