Preparation, Characterization And Catalytic Properties Of Cyclopalladated Bi-arylimine Langmuir-Blodgett(LB) Films

In this thesis, cyclopalladated bi-arylimine were synthesized(Figurel,2and3) and characterized by IR,1H NMR, MS. Heck and Suzuki-Miyaura coupling reaction catalyzed by these pallacycles in homogeneous system were investigated. The behavior of these pallacycles at air/water interface and their LB films used for catalyzing Suzuki-Miyaura were also investigated. The detail research is as follow:1.Synthesis of pallacycles used for catalyzing Suzuki coupling reaction in homogeneous1) Synthesis of cyclopalladated arylimine(A1,B)2) Synthesis and characterization of cyclopalladated bi-arylimine(C)3) Synthesis of bi-arylimine (E)4) Heck and Suzuki coupling reaction catalyzed by pallacycles (A1,B,C)The catalyst (A1,B,C) were applied to catalyze Heck and Suzuki coupling reaction in a homogeneous system; The results showed that the catalyst (A1,B,C) has good catalytic activity. In the optimized experimental conditions, aryl bromides with electron-withdrawing group gave high yield; whereas aryl bromides with electron donating groups gave low yields. The yields of the para-position substitute were higher than that of the ortho-position and the meta-position due to the electron and steric effect.2. Studies on the preparation of cyclopalladated bi-arylimine(A1,B) and bi-arylimine (E) Langmuir-Blodgett (LB) films and their applications in Suzuki-Miyaura coupling reaction1) Fabrication of pallacycles (A1,B) LB films and its catalytic properties for Suzuki coupling reactionThe behavior of pallacycles(A1,B) at air/water interface were investigated. The π-Aisotherms of Aland B showed a rise in the surface pressure with a collapse pressure about20mN/m, suggesting the formation of a stable condensed monolayer (Figure4). Pallacycles(A1,B)monomers could be transferred onto the solid substrate and characterized by AFM and contact angle meter and their LB films were fabricated on the hydrophilic glass substrates under the optimum conditions. LB films of pallacycles(A1,B) were used in the Suzuki reaction, in which higher yield of coupling products could be obtained.2) Bi-arylimine (E) monolayer and its pallacycle self-assembly film The behavior of bi-arylimine (E) at air/water interface were investigated. The π-A isotherm of E showed a rise in the surface pressure with a collapse pressure about20mN/m, suggesting the formation of a stable condensed monolayer (Figure5). Pallacycle E monomer could be transferred onto the solid substrate and characterized by AFM and contact angle meter(Figure6b). Pallacycle self-assembly film of E was completed by dipping E LB films into the lithium palladium chloride aqueous was for48h (Figure6c) and was used for catalyzing Suzuki coupling reaction in which moderate yield could be achieved.