HIGH OXIDATION STATE TRANSITION METAL CHEMISTRY

这项研究的长期目标是确定分子如何 在环境条件下，氮可以被催化还原为氨。 采用定义明确的过渡金属络合物、质子和 电子。短期目标是研究 相对较高的氧化态(主要是)钼或钨的络合物 含有三阴离子三胺基团/给体和相关配体，特别是 与减少氮素有关的化学，包括 含N2Hx(x=0.4)或Nhy(Y=0-3)的络合物的化学 配基。我们希望确定哪些原则是基本的和 对氮气还原为氨的普遍意义。在 过程中，我们也希望保持开放的可能性，以“修复” 以某种氮的形式存在的氮素。含有有机分子。 首先是化学计量，最终是催化作用。具体来说，我们 首先想要制备和研究含有钼或钨的络合物，并已知 三胺胺配体，[(RNCH2CH2)3N]3-(R=三烷基硅基，C6F5)。我们 然后想要准备可能更稳定的变异，其中R (例如)CH(CF3)2或C(C6H5)(CF3)2.含有 也将制备P或作为取代N的供体，并将其连接到Mo和 W为了解决根尖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 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络合物，在这些络合物中，氮可以 被束缚在“笼子”或“洞穴”内，在这种情况下 将消除中间体的双分子分解问题 在脱氮过程中用无机络合物在溶液中还原。

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.