HIGH OXIDATION STATE TRANSITION METAL CHEMISTRY

这项研究的长期目标是确定分子 氮可以在环境条件下催化还原成氨 采用明确定义的过渡金属络合物、质子和 电子。短期目标是研究 （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 与还原二氮有关的化学，包括 含N2 Hx（x = 0.4）或NHy（Y = 0-3）的络合物化学 配体。我们希望确定哪些原则是根本的， 这对将二氮还原为氨具有普遍意义。在 我们也希望对“修复”的可能性保持开放态度。 以氮的形式存在的二氮。含有有机分子， 首先是化学计量的，最后是催化的。我们特别 首先想制备和研究含有Mo或W的配合物， 三酰胺基胺配体，[（RNCH 2CH 2）3 N]3-（R =三烷基甲硅烷基，C6 F5）。 我们 然后想要准备潜在的更稳定的变化，其中R是 （例如）CH（CF 3）2或C（C6 H5）（CF 3）2。类似的配体系统， 还将制备代替N的P或As供体并将其附接至Mo， W，以解决顶端供体配体结合的问题。其他 还将探索各种变体，包括三齿三阴离子配体 例如（[RNC（SiMe 3）2] 3CR ′）3-和三苯并咪唑基胺配体。 最后，我们想合成相关的配合物，其中双氮可以 被束缚和缩小在“笼子”或“空腔”内，这种情况 将消除中间体的双分子分解的问题 在溶液中通过无机络合物还原二氮的过程中。

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.