The Stability Of POCOP Pincer Liganted Ni,Pd,Pt Complexes And Their Application In C-C Coupling Reactions

Transition metal POCOP pincer complexes were first synthesized at the beginning of this century.It is well-known that transition metal POCOP pincer complexes are stable,and their pincer framework can survive in some severe conditions which make them ideal catalysts for many reactions.Studying the stability of POCOP pincer ligand framework is of great significance for expanding the application of POCOP transition metal pincer complexes in the field of catalysis.In this work,the stability of the POCOP pincer framework of nickel,palladium and platinum pincer complexes[2,6-（ⁱPr₂PO）₂C₆H₃]MCl（M=Ni,Pd,Pt）under different conditions was investigated.The main works are specified below:The stability of POCOP nickel,palladium,and platinum pincer complexes [2,6-（ⁱPr₂PO）₂C₆H₃]MCl（M=Ni,Pd,Pt）against excess amounts of nucleophile reagents was investigated.It was found that the POCOP pincer framework backbone is relatively stable under mononuclear nucleophile condition,a series of novel POCOP pincer nickel,palladium and platinum complexes were obtained through exchange reactions.All of these novel complexes were fully characterized by multinuclear NMR,FTIR,HRMS,EA and single crystal X-ray analysis.Meanwhile,the stability of POCOP pincer complexes against excess amounts of binuclear nucleophile reagents was studied.The results showed that the POCOP pincer framework backbone was decomposed under excess binuclear nucleophile reagents conditions,and a possible mechanism was proposed.The stability of POCOP nickel,palladium,and platinum pincer complexes [2,6-（ⁱPr₂PO）₂C₆H₃]MY(M=Ni,Pd,Pt;Y=Ph,o-C₂H₁₁B₁₀)towards electrophilic reagents was investigated.The results showed that the POCOP pincer framework backbone can survive in weak electrophilic conditions but can be completely destroyed by strong electrophilic reagents.A possible decomposition mechanism was proposed.A POCOP nickel pincer complex bearing phenyl auxiliary ligand,[2,6-（ⁱPr₂PO）₂C₆H₃]Ni Ph,was engaged as catalyst for C-C coupling reactions between aryl/alkyl halides and the corresponding Grignard reagents.This complex exhibited good catalytic activities.The reaction proceed via a radical pathway through a Ni（III）intermediate.In summary,we focused on the research of stability of the ligand framework of POCOP nickel, palladium,and platinum pincer complexes[2,6-（ⁱPr₂PO）₂C₆H₃]MCl（M=Ni,Pd,Pt）under different conditions.Meanwhile,a series of novel POCOP nickel,palladium and platinum pincer complexes were obtaind and fully characterized by multinuclear NMR,FTIR,HRMS,EA and single crystal X射线analysis.Additionally,the catalytic application of a novel nickel POCOP pincer complex,[2,6-（ⁱPr₂PO）₂C₆H₃]Ni Ph,in C-C coupling reactions between aryl/alkyl halides and the corresponding Grignard reagents were also investigated.This work is of great importence to the development of the chemistry of transition metal pincer complexes.