Synthesis and ROMP Chemistry of Decafluoroterphenoxide Molybdenum Imido Alkylidene and Ethylene Complexes

The bisDFTO alkylidene complexes of molybdenum Mo(NR)(CHCMe2Ph)(DFTO)(2) (R = 2,6-i-Pr2C6H3, 2,6-Me2C6H3, C6F5, 1-adamantyl; DFTO = 2,6-(C6F5)(2)C6H3O) and monoarylcodde monopyrrolide (MAP) complexes Mo(NR)(CHCMe2Ph)(Me(2)Pyr)-(OAr) (Me(2)Pyr = 2,S-dimethylpyrrolide; R = C6F3, OAr = DFTO, 2,6dimesitylphenoxide (HMTO); R = 2,6-Me2C6H3, OAr = DFTO) have been prepared in good yields. Addition of dicarbomethoxynorbornadiene (DCMNBD) to bisDFTO complexes yielded polymers that have a cis,isotactic structure. Polymerization of DCMNBD by Mo(NC6F5)-(CHCMeiPh)(Me(2)Pyr)(HMTO) gives a polymer that contains the expected cis,syndiotactic structure, but polymerization of DCMNBD by Mo(NR)(CHCMe2Ph)(Me(2)Pyr)(DFTO) (R = C6F5, 2,6-Me2C6H3) generates a polymer that has a cis,isotactic structure, the first observation of a cis,isotactic polymer prepared employing a MAP initiator. Norbornene is polymerized to give what is proposed to be highly tactic cis-polyNBE. Addition of ethylene to Mo(NC6F5)(CHCMe2Ph)(DFTO)(2) leads to formation of Mo(NC6F5)(CH2CH2)-(DFTO)(2), which also behaves as an initiator for polymerization of DCMNBD to cis,isotactic-polyDCMNBD and norbornene to cis highly tactic polyNBE. Mo(NC6F5)(CH2CH2)(DFT0)2 reacts with 3-methyl-3-phenylc-yclopropene (MPCP) to give Mo(NC6F5)(CHCHCMePh)(DFTO)(2) in similar to 50% yield.