Synthesis Of [3, 5-dibromo -2, 6-bis　(2'-oxazolinyl)] Phenylpalladium(Ⅱ) Chloride And Its Catalytic Activity In Suzuki Coupling Reaction

Pincer complex are widely used in many fields, They contain the characteristics of both the C-M (M = metal)σbond and donor-metal coordination. Recent years pincer complexes have attracted much attention. And most researches have been focused on the type of [N, C, N] pincer compounds, in addition, some type of [P, C, P] and [S, C, S] pincer compounds have also been documented. Based on the progress in this field, we have synthesized one type of [N, N] ligand bearing both oxazolinyl and bromo groups.In this paper, a ligand, i.e. [4, 6-dibromo-1, 3-bis(2'-oxazolinyl)]benzene was obtained after a series of reactions from the staring material m-xylene. Treatment of this ligand with palladium acetate (II) and followed by lithium chloride resulted in [3, 5-dibromo-2, 6-bis(2'-oxazolinyl)phenyl]palladium(Ⅱ)chloride. The new compounds and its precursor as mentioned above were fully characterized by IR, NMR spectroscopy.On this basis,the study of the new [N,C,N] palladium compound catalyze the aryl halides and phenylboronic acid in the Suzuki coupling reaction. We have researched the solent,reaction temperature,reaction time,alkaline solution impacted to the Suzuki coupling raction. The sduty found 1,4-dioxane as solvent,K2CO3 as base,at 80℃under 10 hours of the optimal reaction conditions,the Suzuki coupling reaction have the best catalytic effction.The catalytic application of this palladium complex in Suzuki coupling was also examined. It could catalyze the couplings of phenylboronic acid and aryl chlorides where aryl ranged from electron-donating (p-Me, p-MeO) to electron-withdrawing group (p-NO2). The results demonstrate that it shows a higher catalytic activity with a lower loading.