Synthesis,characterization And Catalytic Properties Of Imine–phenol(thiophenol)cobalt And Titanium Complexes

Cobalt and titanium metal complexes were prepared by directly inserting oxygen/sulfur into the C–M bond:cobalt complexes supported by phenol/thiophenol imine ligands were prepared from NCN pincers aldimine;titanium complexes supported by thiophenol ligands were prepared with o-bromoanilide.?²_N,X-^Ar[NXN]Co Cl(THF)(1a,X=O,Ar=2,6-Me₂C₆H₃;1b,X=O,Ar=2,6-ⁱPr₂C₆H₃;2a,X=S,Ar=2,6-Me₂C₆H₃;2b,X=S,Ar=2,6-ⁱPr₂C₆H₃)were prepared by directly inserting O/S into the C–Co bond.O/S was directly inserted into the C–Li bond,and the mixture solution was added different equiv of Co Cl₂ to prepare{?²_N,O-^Ar[NON]Co(?-Cl)₂Li}₂(3a,Ar=2,6-Me₂C₆H₃;3b,Ar=2,6-ⁱPr₂C₆H₃);?²_N,O-^Ar[NON]Co₂Cl₂(?-Cl)₂Li(THF)₂(4a,Ar=2,6-Me₂C₆H₃;4b,Ar=2,6-ⁱPr₂C₆H₃);?²_N,S-^Ar[NSN]Co₂Cl₂(?-Cl)₂Li(THF)₂(5a,Ar=2,6-Me₂C₆H₃;5b,Ar=2,6-ⁱPr₂C₆H₃).We characterized the complexes through Evans test and cultivated crystal of 1b',3b',4a,4b,and 5b.In the polymerization of isoprene,we found that the bimetallic centers complexes are better than the single metal center complexes,because the two cobalt metal centers interact during the polymerization process,which can improve the catalytic activity.We prepared a series of titanium complexes[?_N,S-(2-(Ar¹N=CH)Ar²S)]₂Ti Cl₂(Ar²=C₆H₄,Ar¹=2,6-Me₂C₆H₃(6);Ar¹=2,6-Et₂C₆H₃(7);Ar¹=2,6-ⁱPr₂C₆H₃(8).Ar²=4,6-^tBu₂C₆H₂,Ar¹=2,6-Me₂C₆H₃(9);Ar¹=2,6-ⁱPr₂C₆H₃(10))supported by thiophenol imine ligands.Comparing complexes 6 and 8 with the reported FI catalysts,the titanium center crystal data is not much different,but the bond length of Ti–S is longer than Ti–O.In the polymerization of ethylene,MAO was used as a co-catalyst,and these complexes show moderate activity.