金属卡宾是许多催化反应中的重要中间体。分离关键金属卡宾中间体对相关催化机理的研究起到至关重要的作用。本项目设想利用含大位阻的氮杂环卡宾（NHC）或大位阻膦配体的金属配合物或者通过在底物引入大位阻基团来稳定催化反应中（如共轭碳双键-碳杂双键-炔或炔基甲脒的季胺化关环反应）的后过渡金属（如Au，Cu，Rh，Pd，Zn等）卡宾中间体，从而分离并表征这些关键金属卡宾中间体。通过 X-ray单晶衍射、13C NMR和UV等谱图数据，研究这些金属卡宾中间体的键合性质，特别是金属-卡宾碳键的性质。得到的金属卡宾中间体可以直接研究它们的反应活性，如环丙烷化反应和杂原子（O，S，N，Si）-H键插入反应及六元环金属卡宾的[4+2]环加成反应。这些研究结果，可以帮助我们更好地理解相关过渡金属催化机理，并发展新型的金属卡宾转化反应。

Metal carbenes are key intermediates in many catalytic reactions. It is very important for the mechanism study to isolate the key metal carbene intermediates. The project is focused on the isolation of the key metal carbene intermediates involved in late transition metal-catalyzed cyclization reaction of either the conjugated ene-yne-carbon-heteroatom unsaturated double bond or alkynyl formamidine. By using the transition metal complexes supported by bulky NHC ligands or bulky phosphine ligands or by introduction of sterically hindered substituent into reaction substrates, the active metal carbenes would be stablized and can be isolated. Based on the X-ray diffraction and the data of . NMR and UV/Vis spectra of the resultant metal carbenes, we can investigate their carbene character, especially the property of the metal-carbon bond. The reactivity of the metal carbenes toward cyclopropanation, insertion of heteroatom-H bond, and 4+2 cycloaddition will be aslo study. We could better understand the catalytic mechanism concerning the metal carbene intermediates, and develop novel metal carbene-involved transformation.