HIGH OXIDATION STATE TRANSITION METAL CHEMISTRY

高氧化态过渡金属化学

• 批准号: 2176386
• 负责人: RICHARD R SCHROCK
• 金额: $ 17.08万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 1983
• 资助国家: 美国
• 起止时间: 1983-04-01 至 1998-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2176386
• 关键词: ammonia; catalyst; metal complex; molybdenum; nitrogen; nuclear magnetic resonance spectroscopy; reduction; tungsten; vanadium

The long-term objective of this research is to determine how molecular nitrogen can be reduced to ammonia catalytically under ambient conditions employing a well-defined transition metal complex, protons, and electrons. The short-term objective is to investigate the chemistry of relatively high oxidation state complexes of (primarily) Mo or W that contain trianionic triamido/donor and related ligands, especially chemistry that is relevant to the reduction of dinitrogen, including the chemistry of complexes that contain N2Hx (x = 0.4) or NHy (Y = 0-3) ligands. We wish to determine what principles are of fundamental and general significance to the reduction of dinitrogen to ammonia. In the process we also want to remain open to the possibility of "fixing" dinitrogen in the form of some nitrogen..containing organic molecule, at first stoichiometrically, and ultimately catalytically. Specifically, we first want to prepare and study complexes that contain Mo or W and known triamidoamine ligands, [(RNCH2CH2)3N]3- (R = trialkylsilyl, C6F5). We then want to prepare potentially more stable variations in which R is (e.g.) CH(CF3)2 or C(C6H5)(CF3)2. Analogous ligand systems that contain P or As donors in place of N will also be prepared and attached to Mo and W in order to address the issue of apical donor ligand binding. Other variations will also be explored, including tridentate trianionic ligands such as ([RNC(SiMe3)2]3CR')3- and tribenzimidazolatoamine ligands. Finally we want to synthesize related complexes in which dinitrogen could be bound and reduced within a "cage" or "cavity," a circumstance that would eliminate the problem of bimolecular decomposition of intermediates in the dinitrogen reduction process by inorganic complexes in solution.

这项研究的长期目标是确定分子如何 氮可以在环境条件下催化还原为氨 采用明确的过渡金属配合物、质子和 电子。短期目标是研究化学 （主要）Mo 或 W 的相对高氧化态络合物 含有三阴离子三酰氨基/供体和相关配体，特别是 与二氮还原相关的化学，包括 含有 N2Hx (x = 0.4) 或 NHy (Y = 0-3) 的络合物的化学性质 配体。我们希望确定哪些原则是根本性的和 对于将二氮还原成氨具有一般意义。在 我们还希望对“修复”的可能性保持开放态度 二氮以某种含氮有机分子的形式存在，在 首先是化学计量的，最后是催化的。具体来说，我们 首先要制备和研究含有 Mo 或 W 且已知的配合物 三酰氨基胺配体，[(RNCH2CH2)3N]3-（R = 三烷基甲硅烷基，C6F5）。 我们 然后想要准备潜在更稳定的变化，其中 R 是 （例如）CH(CF3)2 或 C(C6H5)(CF3)2。类似的配体系统包含 代替 N 的 P 或 As 供体也将被制备并连接到 Mo 和 W为了解决顶端供体配体结合的问题。其他 还将探索各种变化，包括三齿三阴离子配体 例如([RNC(SiMe3)2]3CR')3-和三苯并咪唑胺配体。 最后我们想要合成相关的复合物，其中二氮可以 被束缚并减少在“笼子”或“空腔”内，这种情况 将消除中间体双分子分解的问题 在溶液中无机络合物的二氮还原过程中。