Palladium Complexes with N,O-Bidentate Ligands Based on N-Oxide Units from Cyclic Secondary Amines:Synthesis and Catalytic Application in Mizoroki-Heck Reaction

Palladium-catalyzed Mizoroki-Heck reaction is a powerful and efficient method for construction of Csp2–Csp2 bonds.Herein,four palladium complexes(I—IV)with N,O-bidentate ligands(L1—L4)based on N-oxide units from cyclic secondary amines were easily synthesized and successfully applied in Mizoroki-Heck reaction of aryl bromides with electron-deficient olefins.X-ray diffraction analyses indicated the palladium(II)atom of II took the distorted square planar geometry and was four-coordinated by nitrogen and oxygen atoms from two ligands(L2).Two free chloride ions were presented as counter anions in complex II.But the palladium(II)center of IV was coordinated by nitrogen and oxygen atoms from one ligand(L4)as well as two chlorine atoms,which exhibited the nearly square-planar geometry.The study on catalytic properties of palladium complexes revealed that complex II exhibited high activity superior to the other complexes.The coupling reactions of a series of aryl bromides and olefin derivatives proceeded in the presence of 2—5 mol%palladium complex II,giving the desired products in good to excellent yields.The advantages of this method such as good compatibility of functional groups,high yields,and short reaction times made it more attractive for constructing Csp2–Csp2 bonds in the synthesis of functional molecules and materials.

基于可持续发展的PPP项目预防性治理模式研究

PPP项目的可持续发展是项目成功的关键因素,它受到项目利益相关方微观行为的影响,因此,为提高项目可持续发展需要从控制项目利益相关方微观行为着手。项目利益相关方微观行为包括网络个体、网络关系、网络环境,分别可以使用转移方式系数、网络边权、约束参数来表征。PPP项目的可持续发展指标在不同情形下可以使用直径、聚集系数、内度稳定性来表征,而这些稳定性指标由项目利益相关方在网络形成阶段的微观行为所决定,即前摄网络稳定性。在PPP项目网络的初始、发展、调整、结束阶段,应时刻关注项目的可持续发展指标,即可持续发展的预防性治理。本文研究了前摄PPP项目网络稳定性和项目利益相关方微观行为的相互作用机理,相应地,提出了PPP项目可持续发展的三种预防性治理模式,即政府主导模式、企业主导模式、协作交互模式三种不同的治理模式,这些治理模式为提高PPP项目的可持续发展提供了一定的理论基础。