有机膦溴化钯(Ⅱ)配合物的合成、结构及其催化偶联反应活性

以PdBr₂为起始原料,分别选择二叔丁基苯基膦((t-Bu)₂PPh)、二叔丁基-(4-二甲基氨基苯基)膦(Amphos)、4,5-双二苯基膦-9,9-二甲基氧杂蒽(Xantphos)为有机膦配体,通过溶剂的配位加成和有机膦的配位取代,合成出3种溴化钯配合物,以寻找性能更佳的偶联催化剂。借助元素分析仪、核磁共振仪及单晶X射线衍射仪测试和解析了它们的化学结构,分别trans-Pd((t-Bu)₂PPh)₂Br₂(1),trans-Pd(Amphos)Br₂]₂(2)、cis-Pd(Xantphos)Br₂(3),其中的trans-Pd(Amphos)Br₂]₂(2)为溴桥双核钯配合物。选用了2个Suzuki偶联反应为评价模型,测试了它们的催化活性,并分别与市售的Pd((t-Bu)₂PPh)₂Cl₂、Pd(Amphos)₂Cl₂、Pd(Xantphos)Cl₂进行对照试验,结果表明:在选定的模型上,2个有机膦钯(Ⅱ)配合物的产率均高于对应的有机膦氯化钯(Ⅱ)催化剂。

Synthesis,Structure and Catalytic Activity of Three Organophosphine Bromo Palladium(Ⅱ)Complexes for Coupling Reactions

Three new palladium(Ⅱ)complexes with Br-as the dissociation ligand and with di-tert-butylphenyl phosphine((t-Bu)₂PPh),di-tert-butyl-(4-dimethylaminophenyl)phosphine(Amphos)or 4,5-bis(diphenyl-phosphino)-9,9-dimethylxanthene(Xantphos)as the organic phosphine ligand,were prepared from the starting material PdBr₂via the coordination addition and ligand substitution process,with an attempt to develop more effective organophosphinopalladium catalysts for the coupling reactions.The palladium(Ⅱ)complexes were tested and characterized by elemental analysis,1 H NMR and single-crystal X-ray diffraction analysis to be trans-Pd((t-Bu)₂PPh)₂Br₂(1),trans-Pd(Amphos)Br₂]₂(2),cis-Pd(Xantphos)Br₂(3).Among them,trans-Pd(Amphos)Br₂]₂is a unique binuclear palladium complex in which two bromine ions act as the bridging ligand bringing twoPd(Amphos)Br]blocks together.Two typical Suzuki organic coupling reaction models were used for evaluating the catalytic activity of three complexes along with commercially available Pd((t-Bu)₂PPh)₂Cl₂,Pd(Amphos)2 Cl₂and Pd(Xantphos)Cl₂as comparison catalysts.The results showed all three complexes displayed high catalytic activity in two selected typical Suzuki organic coupling reactions,greater than the corresponding values of Pd((t-Bu)₂PPh)₂Cl₂,Pd(Amphos)2 Cl₂and Pd(Xantphos)Cl₂.CCDC:2039381,1;2039380,2;2039382,3.