Study On The Reactions Involved Carbon-halogen Bond Activation Based On The Catalvzation By Iridium Complexes

Aromatic halides have received great attention in the field of organic synthetic chemistry.C-X bonds have their own unique properties that are otherwise difficult to obtain because oftheir chemical inertness especially C-F bonds, but these properties also caused organofluorinecompounds’ limited utilization in syntheses processes. Therefore, it has become greatchallenges bearing impressive meaning in modern synthetic organic chemistry to improve theactivation methodologies for aromatic C-F bonds.According to the study on the reaction of2-（2,4-difluorophenyl）pyridine cyclometalatedIr（III） μ-chloro-bridged dimmer with sodium methoxide which is a strong organic base underthe nitrogen atmosphere in2-ethoxyethanol, we found the reaction can give a product havinga newly found structure. The structure of the product was confirmed by severalcharacterization methods like IR, NMR, X-Ray single crystal diffraction, elemental analysis,mass spectrum. Based on the study of the product’s structure, we put forward a correspondingmechanism of the reaction and verified it by giving out the proof of the presence of theintermediates and by-products through numerous detection means, such as HPLC-MS,1H-NMR,19F-NMR. Through the study of the mechanism, regularities of the activation ofaromatic C-F bonds were understood.Besides, the syntheses and the structure’s characterization of IrH（PPh₃）₄, IrH（CO）（PPh₃）₃were also described in this paper. The utilization of them as catalyst in the activation of theC-F bonds was also discussed. Using several aromatic flourocompounds asp-nitrofluorobenzene and various organosulfur compounds as bis（m-methoxyphenyl）disulfideworked as reactant, the capability of IrH（PPh₃）₄and IrH（CO）（PPh₃）₃served as catalyst in thetransformation of C-F bond into C-S bond and the influence factor of these reactions werestudied. The confirmation of products’ structure was conducted by means of melting point test,IR and NMR methods. In addition, reactions of C-F bond transformed into C-N bond wereproceeded using several aromatic flourocompounds as p-nitrofluorobenzene and variousorganonitrogen compounds as piperazine and methanesulfonamide worked as reactant andIrH（CO）（PPh₃）₃worked as catalyst. The capability of the catalyst and the influence factor ofthese reactions were studied. Characterizations of the product were given out. The promotionof activation of C-F bonds by iridium complexes as catalyst was demonstrated under thecomparison experiments.