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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.

金属转化是构成同源偶联、交叉偶联、烯烃聚合等合成有机反应的重要基本反应之一。本研究旨在阐明有机过渡金属配合物的金属转化机理。具有叔磷配体的芳基钯炔基配合物在室温下与芳基钯碘配合物反应，引起分子间炔基配体转移，生成新的有机钯配合物。炔基钯键比芳基钯键在热力学上更稳定，但反应性更强，因为炔基配体与桥接炔基配体的中间双核配合物的高稳定性有利于炔基配体的转金属。类似的炔基配体从Pd转移到Pt配合物需要更高的温度或添加CuI催化剂。二炔基钯和铂配合物与这些金属的二碘配合物通过炔基配体的转金属反应生成配合物。产物的分布受配合物的热力学稳定性和催化剂的存在与否的影响。Arylpalladium碘复合物与螯合二元胺不会导致分子间芳基配体转移,而阳离子物种准备从添加AgBFィイD24ィエD2的复合物进行歧化给diarylpalladium复合物。产物通过还原消除得到联芳基，这与10族金属配合物催化的均偶联反应机理有关。芳香基的种类对转化速率的影响很大；含氟芳基配体的配合物对金属转化反应性较低。综上所述，本研究揭示了有机过渡金属配合物跨金属化的各个方面，并阐明了跨金属化作为关键步骤的几种合成有机反应的机理。