Cleavage and Formation of Carbon-Carbon Bonds by Transition Metal Complexes

过渡金属配合物对碳-碳键的断裂和形成

• 批准号: 8907397
• 负责人: Russell Hughes
• 金额: $ 23.26万
• 依托单位: Dartmouth College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-06-01 至 1992-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8907397&HistoricalAwards=false
• 关键词: Cleavage; Formation; Carbon; Bonds; Transition

The long term objective of this project in the Inorganic, Bioinorganic and Organometallic Chemistry Program is to achieve greater understanding of how transition metal compounds can effect the cleavage and formation of carbon-carbon bonds. Such reactions are among the most important in chemistry and are involved in industrial processes such as reforming gasoline to upgrade the octane number. The overall strategy of the project is to isolate and model the individual steps of organic transformations involving C-C bond forming or cleavage as effected both stoichiometrically and catalytically by transition metal reagents. Emphasis will be placed on compounds with cyclopropenyl, cyclopropene and vinylcylclopropene ligands. Reactions of perfluorocyclopropene with transition metal centers will serve as a model for the C-C bond cleavage reaction, with oxidative addition of the C-C bond providing a route to metallacyclobutene complexes. The mechanism of transformation of 3-vinyl-1-cyclopropenes into 1,3-cyclopentadienes, or into eta-5-cyclopentadienyl(hydrido) metal complexes, are of particular interest since sequential C-C bond cleavage and C-C bond formation steps are involved. For some Rh- and Ir-promoted reactions intermediates can be isolated, and the structures of these intermediates demonstrate that the mechanism for opening the cyclopropene ring is more complicated than for simpler cyclopropenes, and cannot involve a "simple" oxidative insertion of the metal into the C-C bond. Reactions of selectively isotopically labelled precursors will be used to map the course of the novel skeletal rearrangements, corresponding to previously unknown organometallic transformations, which occur during the ring opening reactions. Isotopically labeled precursors will be used also to further elucidate the mechanism of the C-C bond forming reaction whereby 1,2,3,5-eta-pentadienediyl and 1,5-eta-pentadienediyl- (1-metallacyclohexa-2,4-diene) complexes of Rh(III) and Ir(III) undergo conversion to eta-5-cyclopentadienyl(hydrido) metal compounds.

这个项目在无机物方面的长期目标是， 生物无机和有机化学计划是为了实现 更好地理解过渡金属化合物如何 影响碳-碳键的断裂和形成。等 反应是化学中最重要的反应之一， 涉及工业过程，如重整汽油， 提高辛烷值。 该项目的总体策略是隔离和建模 涉及C-C键的有机转化的各个步骤 形成或裂解的化学计量和 通过过渡金属试剂催化。重点将 置于具有环丙烯基、环丙烯和 乙烯基环丙烯配体。全氟环丙烯的反应 具有过渡金属中心将作为C-C模型 键断裂反应，伴随C-C键的氧化加成 提供了金属环丁烯络合物的途径。的 3-乙烯基-1-环丙烯转化为 1，3-环戊二烯，或转化为eta-5-环戊二烯（β-环戊二烯） 金属络合物是特别令人感兴趣的，因为顺序 涉及C-C键断裂和C-C键形成步骤。 对于一些Rh和Ir促进的反应，中间体可以是 分离，这些中间体的结构证明 打开环丙烯环的机制 比简单的环丙烯复杂，并且不能涉及 金属“简单”氧化插入C-C键。 选择性同位素标记的前体的反应将 用于绘制新的骨骼重排的过程， 对应于以前未知的有机金属 在开环反应期间发生的转化。 同位素标记的前体也将用于进一步 阐明了C-C键形成反应的机理 其中1，2，3，5-η-环己烯二基和1，5-η-环己烯二基- Rh（III）和Ir（III）的（1-金属环己-2，4-二烯）配合物 转化为η-5-Al 2 O3（Al 2 O3）金属 化合物.