Chemistry of the metal carbonyls. Part LXX. Trimethylsilyl, trimethylgermyl, and trimethylstannyl derivatives of cyclo-octatetraene and their complexes with the tricarbonyliron group

Abstract

Reactions of the compounds Me₃MCl (M = Si or Sn) and Me₃GeBr with diethyl ether solutions obtained by treating bromocyclo-octatetraene with n-butyl-lithium at –80 °C afford the monosubstituted cyclo-octatetraene compounds C₈H₇MMe₃. The complex [Fe(CO)₂(C₈H₇)(η-C₅H₅)] has been similarly prepared from [FeCl-(CO)₂(η-C₅H₅)]. These cyclo-octatetraene derivatives react with enneacarbonyldi-iron to yield complexes of the tricarbonyliron group; the silicon and tin derivatives also form binuclear iron complexes [Fe₂(CO)₆(C₈H₇-MMe₃)]. The complexes [Fe(CO)₃(C₈H₇MMe₃)](M = Si or Ge) react with Ph₃CBF₄ to yield tetrafluoroborate salts which on hydrolysis give complexes [Fe(CO)₃{C₈H₆(MMe₃)(CPh₃)}] containing disubstituted cyclo-octatetraene ligands.