Intermolecular transfer of organic ligands among transition metal complexes

过渡金属配合物之间有机配体的分子间转移

基本信息

批准号：
09440229
负责人：
OSAKADA Kohtaro
金额：
$ 8.9万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

Transmetalation is one of the important fundamental reactions which constitute of synthetic organic reactions such as homo- and cross-coupling and alkene polymerization. This study aimed elucidation of detailed mechanism of transmetalation of organotransition metal complexes. Arylpalladium alkynyl complexes with tertiary phosphime ligands react with arylpalladium iodo complexes below room temperature to cause intermoelcular alkynyl ligand transfer to give new organopalladium complexes. Alkynyl-palladium bond is thermodynamically more stable than the aryl-palladium bond but much more reactive because the transmetalation of the alkynyl ligand is favored by high stability of intermediate dinuclear complexes with bridging alkynyl ligand. Similar alkynyl ligand transfer from Pd to Pt complexes requires higher termperature or addition of CuI catalyst.Dialkynylpalladium and platinum complexes react with diiodo complexes of these metals to cause the complexes via transmetalation of the alkynyl ligands. Distribution of the product is influenced by thermodynamic stability of the complexes and the presence or absence of CuI catalyst which enhances the reaction significantly.Arylpalladium iodo complexes with chelating diamines do not cause intermolecular aryl ligand transfer, whereas the cationic species prepared from addition of AgBFィイD24ィエD2 to the complexes undergo disproportionation to give diarylpalladium complexes. The product give biaryl via reductive elimination, which is related to the mechanism of homocoupling reaction catalyzed by group 10 metal complexes. Rates of the transmetalation depend highly on kinds of aryl group; the complexes with fluorinated aryl ligand exhibit low reactivity toward the transmetalation.In summary, the present study has revealed various aspects of transmetalation of organotransition metal complexes and elucidated the mechanism of several synthetic organic reactions that involve transmetalation as a crucial step.

金属转移是构成均相偶联、交叉偶联和烯烃聚合等有机合成反应的重要基础反应之一，本研究旨在阐明具有叔磷配体的芳基钯炔基配合物与芳基钯反应的详细机理。低于室温的碘配合物引起分子间炔基配体转移，产生新的有机钯炔基-钯键在热力学上比芳基-钯键更稳定，但更具反应性，因为具有桥连炔基配体的中间双核配合物的高稳定性有利于炔基配体从Pd转移到Pt配合物。需要更高的温度或添加 CuI 催化剂。二炔基钯和铂络合物与这些的二碘络合物反应金属通过炔基配体的金属转移作用形成络合物，产物的分布受络合物的热力学稳定性以及 CuI 催化剂存在或不存在的影响，CuI 催化剂会显着增强反应。具有螯合二胺的芳基钯碘络合物不会引起分子间芳基配体。转移，而通过将 AgBFiiD24 添加到复合物中制备的阳离子物质经历歧化以产生二芳基钯配合物通过还原消除得到联芳基，这与第10族金属配合物催化的自偶联反应机制有关，金属转移的速率很大程度上取决于芳基的种类，具有氟化芳基配体的配合物表现出较低的反应活性。总之，本研究揭示了有机过渡金属配合物的金属转移的各个方面，并阐明了几种机制涉及金属交换作为关键步骤的合成有机反应。