Synthesis of Tungsten Imido Alkylidene Complexes that Contain an Electron-Withdrawing Imido Ligand

Tungsten NAr R alkylidene complexes have been prepared that contain the electron-withdrawing Ar R groups 2,4,6-X 3 C 6 H 2 (Ar X3 , X = Cl, Br), 2,6-Cl 2 -4-CF 3 C 6 H 2 (Ar Cl2CF3 ), and 3,5-(CF 3 ) 2 C 6 H 3 (Ar (CF3)2 ). Reported complexes include W(NAr R ) 2 Cl 2 (dme) (dme = 1,2-dimethoxyethane), W(NAr R ) 2 (CH 2 CMe 3 ) 2 , W(NAr R )(CHCMe 3 )(OTf) 2 (dme), and W(NAr R )(CHCMe 3 )(ODBMP) 2 (DBMP = 4-Me-2,6-(CHPh 2 )C 6 H 2 ). The W(NAr R )(CHCMe 3 )(ODBMP) 2 complexes were explored as initiators for the polymerization of 2,3-dicarbomethoxynorbornadiene (DCMNBD).