HIGH OXIDATION STATE TUNGSTEN AND MOLYBDENUM DINITROGEN

高氧化态钨和二氮钼

• 批准号: 3280447
• 负责人: RICHARD R SCHROCK
• 金额: $ 14.77万
• 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 1991-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3280447
• 关键词: Raman spectrometry; X ray crystallography; ammonia; chemical structure; chemical substitution; hydrazines; ligands; metal complex; molybdenum; nitrogen; oxidation; thiols; tungsten

The specific aims of this project are (1) to discover what types of ditungsten and dimolybdenum Mu-hydrazido(4-) complexes can be prepared in which the metal is in its highest possible oxidation state; (2) to replace chloride or alkyl ligands in such complexes with thiolate ligands in an effort to come as close as possible to a sulfur coordination sphere related to that around molybdenum in nitrogenase; (3) to discover what factors determine whether hydrazine or ammonia is formed by a combination of protonation/reduction steps; (4) to design and study systems that will coordinate dinitrogen between two of the same or two different metals to give Mu-hydrazido(4-) complexes analogous to those previously prepared. We have recently shown that it is possible to make Mu-dinitrogen complexes by reducing a monopentamethylcyclopentadienyl complex of tungsten(V) under dinitrogen. This cyclopentadienyl system seems to be the most likely area to look for other dinitrogen complexes containing more relevant alkoxide or thiolate ligands bound to the metal. It also should be extendable to molybdenum. Both molybdenum and tungsten complexes of the type MX4 (X = alkoxide or thiolate) is another area ripe for exploration. A third area concerns the use of ligands that link two metals together at a distance that is appropriate (about 4.8A) for nitrogen to coordinate between the two metals. Ligands such as linked cyclopentadienyl ligands, dimethyl resorcinol, or dimethyl dithiaresorcinol are high on the list. The recent discovery of the especially high reactivity of phenoxide-substituted tungsten alkylidyne complexes toward the carbonyl group suggests that we will be able to prepare vinyltrialkoxytungsten dinitrogen complexes from alkylidyne complexes and azines. The synthetic studies will be complemented by electrochemical, x-ray structural, and Raman studies of the most relevant complexes.

该项目的具体目标是 (1) 发现什么类型 二钨和二钼 Mu-酰肼(4-)络合物可以通过以下方式制备 金属处于其可能的最高氧化态； (2) 更换 此类络合物中的氯化物或烷基配体与硫醇盐配体 努力尽可能接近相关的硫配位范围 固氮酶中钼周围的区域； (3) 找出哪些因素 确定肼或氨是否由以下物质的组合形成 质子化/还原步骤； (4) 设计和研究系统 在两种相同或两种不同金属之间配位二氮 得到类似于先前制备的Mu-酰肼(4-)络合物。 我们最近证明可以制造 Mu-二氮络合物 通过在以下条件下还原钨(V)的单五甲基环戊二烯基络合物 二氮。 该环戊二烯基系统似乎是最有可能的区域 寻找含有更多相关醇盐的其他二氮络合物或 硫醇盐配体与金属结合。 它也应该可以扩展到 钼。 MX4 型钼和钨络合物（X = 醇盐或 硫醇盐）是另一个值得探索的领域。 第三个领域涉及使用配体将两种金属以一定的速度连接在一起。 适合氮配位的距离（约4.8A） 两种金属之间。 配体例如连接的环戊二烯基配体， 二甲基间苯二酚或二甲基二硫代间苯二酚名列前茅。 最近发现特别高的反应活性 羰基苯氧基取代亚烷基钨配合物 小组建议我们将能够制备乙烯基三烷氧基钨 来自亚烷基络合物和吖嗪的二氮络合物。 合成研究将得到电化学、X 射线的补充 最相关配合物的结构和拉曼研究。