Studies On The The Unsymmetric NCN-palladium Pincer Complex Synthesis And Catalytic In Sonogashira Coupling Reaction

In this thesis, there are two kinds of 3-(pyridin-2-yloxy)benzaldehyde ligands and the corresponding pincer palladium compounds were synthesized. The new compounds were characterized and applied in the Sonogashira coupling reaction as catalysts. The main results are shown as follows:1. The synthesis of the new Asymmetric NCN pincer palladium complexesThe ligands la-d (Scheme 1) were synthesized by the condensation of m-hydroxy-benzaldehyde with amine in CH2Cl2 at the room temperature, then followed by the addition of palladium chloride to obtain the new asymmetric NCN pincer Pd (Ⅱ) complexes 2a-d. All of them were characterized by IR,1H NMR,13C NMR and MS.The compounds 3a-d were carried out by the reduction of la-d by NaBHU, and PdCl2 was addided into the refluxing toluene under N2 surroundings to produce the corresponding pincer palladium complexes 4a-d. (Scheme 2) These new pincer palladium complexes 4a-b were characterized by 1H NMR, 13C NMR, IR and MS spectra. Meanwhile, the molecular structures of 2b,2d,4a were determined by X-ray single-crystal diffraction. 11.The application of the new pincer palladium complexes 2a-d and 4a-d in Sonogashira reactionThe new pincer palladium complex 2a-d and 4a-d were used in palladium catalyzed Sonogashira cross coupling reation of aryl halides with terminal alkenes. We found that using 2 mol% of 2b in H2O with K3PO4 as base catalyst at 70℃for 12 h, and the coupled products of aryl halides with terminal alkenes could be obtained as high as 99%.(Scheme 3).