Synthesis,Structure,and Solution Behavior of 1-Chloro-2,2-difluorovinyl Titanocene Derivatives:The First X-ray Study of a Titanium Fluorovinyl Compound and Spectroscopic Elucidation of the [Cp_2TiMe(eta~2-CF_2=CClH)] Complex

摘要

The first early-transition-metal l-chloro-2,2-difluorovinyl complexes [Cp_2TiX_n(CCl=CF_2)_(2-n)] (X=Cl,F;n=0,1) have been synthesized by the low-temperature reaction of Cp_2TiX_2 (X=Cl,F) with (l-chloro-2,2-difluorovinyl)lithum,generated in situ from HCFC-133a (CF_3-CH_2C1) and n-butyllithium.The complexes have been characterized by spectroscopy and,in the case of [Cp_2TiCl(CCl=CF_2)],by single crystal X-ray diffraction,making this the first structurally characterized titanium-based fluorovinyl compound.The marked solution-phase instability of these materials has been explored in an attempt to identify key characteristics that might lead to stabilized systems.To this end,syntheses of the compounds [Cp_2~*TiF_n-(CF=CF_2)_(2-n)] (n= 0,1) and [Cp_2TiMe(CCl=CF_2)] have been reported and their stabilities investigated further.In the case of [Cp_2TiMe(CCl=CF_2)],this has led to the spectroscopic characterization of the pi-complex [Cp_2TiMe(eta~2-CF_2=CClH)] as an intermediate in the solution-phase decomposition pathway.