Preparation,Characterization And Catalytic Performance About Ethylenediamine/Polyamidoamine-2-Pyridinecarbaldehyde Schiff Base Palladium

Firstly, a series of schiff bases were prepared by the condensation reaction of ethylenediamine or polyamidoamine dendrimer with2-pyridinecarbaldehyde, then schiff base palladium complexes were synthesized by the reaction of schiff base with Li2PdCl4. Secondly, the structures of these schiff bases and schiff base palladium complexes were characterized by the analytic instruments. Finally, catalytic performance of these schiff base palladium complexes in Heck reaction were investigated. Specific research contents and conclusions are as follows:1. Preparation and characterization of ethylenediamine-2-pyridinecarbaldehyde schiff base palladium complexEthylenediamine-2-pyridinecarbaldehyde schiff base (EDAPy) was prepared by the reaction of ethylenediamine with2-pyridinecarbaldehyde, then ethylenediamine-2-pyridinecarbaldehyde schiff base palladium complex (EDAPy-Pd) was synthesized by EDAPy reacting with Li2PdCl4-The structures of EDAPy and EDAPy-Pd were characterized by FT-IR, NMR, HRMS, elemental analysis and ICP. According to the results of characterization, the structure of EDAPy-Pd was proposed.2. Catalytic performance of ethylenediamine-2-pyridinecarbaldehyde schiff base palladium complex in Heck reactionUsing EDAPy-Pd as catalyst, catalytic performance was studied in Heck reaction in organic solvent. Effects of different reaction conditions (including reaction temperature, reaction time, molar ratio of iodobenzene to acrylic acid, kinds and amount of base and amount of catalyst and kinds of solvent) on the yield of cinnamate were explored. The optimum reaction condition about the reaction of iodobenzene with acrylic acid was:10mmol iodobenzene, triethylamine as base, nphI: nAA:nEt3N=1:1.5:2,5mL DMF as solvent,1.6mg (npd=5.4×10-3mmol) catalyst,100℃for30min under N2gas. Cinnamate yield can reach up to92.2%under the optimum condition. 3. Preparation and characterization of polyamidoamine-2-pyridinecarbaldehyde schiff base palladium complexesPolyamidoamine-2-pyridinecarbaldehyde schiff bases (1.0-5.0G PAMAMPy) were prepared by the condensation reaction of1.0-5.0G PAMAM with2-pyridinecarbaldehyde. Using1.0-5.0G PAMAMPy as ligands, Polyamidoamine-2-pyridinecarbaldehyde schiff base palladium complexes (1.0-5.0G PAMAMPy-Pd) were synthesized. The structures of1.0-5.0G PAMAMPy-Pd were characterized by FT-IR, elemental analysis, ICP and TG-DSC.4. Catalytic performance of5.0G PAMAMPy-Pd in Heck reaction in organic solventUsing5.0G PAMAMPy-Pd as catalyst, the optimum reaction condition in the Heck reaction of iodobenzene with acrylic acid was researched. The optimum reaction condition was:10mmol iodobenzene, triethylamine as base,nPhI:nAA:nEt3N=1:1.4:2.5,5mL DMF as solvent,3.0mg (nPd=6.1×10-3mmol)5.0G PAMAMPy-Pd,100℃for25min under N2. Cinnamate yield can reach up to90.1%in DMF.5.0G PAMAMPy-Pd can be filtered, washed with solvent and reused. The yield of product still can reach up to82.0%at third time.5. Catalytic performance of1.0-5.0G PAMAMPy-Pd in Heck reaction in DMFUsing1.0-5.0G PAMAMPy-Pd as catalyst, the catalytic performances in Heck reaction of iodobenzene or its derivatives with conjugated olefins were studied in DMF under the optimum reaction condition.1.0-5.0G PAMAMPy-Pd showed positive catalytic activity compared to PdCl2.6. Catalytic performance of1.0-5.0G PAMAMPy-Pd in Heck reaction in water.Using1.0-5.0G PAMAMPy-Pd as catalyst, the catalytic performances in Heck reaction of iodobenzene or its derivatives with conjugated olefins were studied in water. Compared to PdCl2,1.0-5.0G PAMAMPy-Pd showed the better catalytic activities in the Heck reaction of iodobenzene or its derivatives and conjugated olefins, the yield can reach more than65%.