Abstract
1-Trimethylsilyl, 1-R (R = Me, Et, i-Bu)-2,3,4,5-tetraphenyl-1-silacyclopentadiene [[Ph₄C₄Si(SiMe₃)]R] are synthesized from the reaction of 1-trimethylsilyl,1-lithio-2,3,4,5-tetraphenyl-1-silacyclopentadienide anion [[Ph₄C₄Si(SiMe₃]⁻•[Li]⁺ (3) with methyl iodide, ethyl iodide, and i-butyl bromide. The versatile intermediate 3 is prepared by hemisilylation of the silole dianion [Ph₄C₄Si]⁻²•2[Li]⁺ (2) with trimethylsilyl chloride and characterized by ¹H-, ¹³C-, and ²⁹Si-NMR spectroscopy. 1,1-bis(R)-2,3,4,5-tetraphenyl-1-silacyclopentadiene [Ph₄C₄SiR₂] {R = n-Bu (7); t-Bu (8)} are synthesized from the reaction of 2 with n-butyl bromide and t-butyl bromide. Reduction of 7 and 8 with lithium under sonication gives the respective 3-silolenide 2,5-carbodianions {[Ph₄C₄Si(n-Bu)₂]⁻²•2[Li]⁺ (10) and {[Ph₄C₄Si(t-Bu)₂]⁻²•2[Li]⁺ (11)}, which are characterized by ¹H-, ¹³C-, and ²⁹Si-NMR spectroscopy. Polarization of phenyl groups in 3 is compared with those of silole anion/dianion, germole anion/dianion, and 3-silolenide 2,5-carbodianions 10 and 11.