Preparation, Characterization And Catalytic Properties Of Amphiphilic Cyclopalladated Polymers And Their Langmuir-blodgett(lb) Films

In the thesis, the synthesis, characterization and the crystal structures of a seriesof new cyclopalladated monomers and their polymer were reported. Langmuirmonolayers and Langmuir-Blodgett (LB) films of these monomers and their polymersare fabricated and characterized. Suzuki cross-coupling reaction catalyzed by thesecomplexes in heterogeneous system are studied. Good catalytic reactivity areacquired in their LB films which is transferred onto the hydrophilic glass substrates.Moreover, the mechanic of Suzuki reaction in heterogeneous system was alsoinvestigated.1. A series of amphiphilic cyclopalladated monomers (4a-c)(Scheme1) weresynthesized and characterized by1H NMR,13C NMR,31P NMR, IR and MS. Thecrystal structures of4a-c were determined by X-ray crystallography. Their catalyticproperties for Suzuki cross-coupling reactions were investigated in homogenoussystem.Scheme1Synthesis route of cyclopalladated imine2. Langmuir monolayers and LB films of cyclopalladated monomers (4a-c) weresuccessfully fabricated and characterized in optimal surface pressure and used forcatalyzing the Suzuki reaction in heterogeneous system. The results of catalysisshowed that one-layer film of4c deposited onto solid slides had high yield and TONfor the Suzuki reaction and could be reused three times. the mechanic of Suzukireaction showed that the reaction was occurred in the surface of the substrate. Pd(Ⅱ)was play great role in heterogeneous system while there is a synergy interaction between cyclopalladated monomers and substrates.Scheme2Plausible interface catalysis for Suzuki coupling reaction3. Langmuir monolayers of cyclopalladated polymers (Scheme3) were preparedand characterized and used for catalyzing the Suzuki reaction in heterogeneoussystem. The result showed that different molecular weight had different yield.Meanwhile, The TON of polymers reached105, which was much higher than that ofthe monomers.Scheme3Synthesis of cyclopalladated polymer4. The polymer monolayer was just reused for one time. It was likely that thesubstrate and product were adsorbed on catalyst molecular, indicating that the amountof catalytic center was covered and poor reuse. The mechanic of Suzuki reactionshowed that the reaction was occurred in the surface of the substrate while Pd(Ⅱ)played great role in the catalysis.