title: Synthesis and spectroscopic studies of arylethynylsilanes.
abstract: A variety of arylethynylsilanes (Ar-C[triple bond]C-C6H4-C[triple bond]C)(n)SiMe(4-n) were prepared successfully by reaction of the corresponding chlorosilanes Me(4-n)SiCl(n) with Ar-C[triple bond]C-C6H4-C[triple bond]CM (M = Li, MgBr), which was prepared by treatment of ethynyl(diarylethyne)s Ar-C[triple bond]C-C6H4-C[triple bond]CH with BuLi or MeMgBr. The ethynyl(diarylethyne)s were readily prepared in good yields by the double-elimination method: addition of lithium hexamethyldisilazide to a mixture of ArCH2SO2Ph, TMS-C[triple bond]C-C6H4-CHO, and ClP(O)(OEt)2, followed by desilylation. In the tetrakis(arylethynyl)silanes (Ar-C[triple bond]C-C6H4-C[triple bond]C)4Si thus prepared, through-space conjugation of four triple bonds on the silicon atom emerges as a result of participation of the silicon orbitals in the acetylenic pi orbitals. This participation enhances the emissive quantum yields of arylethynylsilanes with an increase in the number of arylethynyl moieties on silicon: quantum yields of emission (phiF) of 0.72 for (MeOC6H4-C[triple bond]C-C6H4-C[triple bond]C)4Si, 0.53 for (MeOC6H4-C[triple bond]C-C6H4-C[triple bond]C)2SiMe2, and 0.47 for MeO-C6H4-C[triple bond]C-C6H4-C[triple bond]CSiMe3 were obtained. Although this enhancement effect was also observed in the phenylethynylarylsilane (MeOC6H4-C[triple bond]C-C6H4)2SiMe2, the bis(arylethynyl)disilane (MeOC6H4-C[triple bond]C-C6H4-C[triple bond]C-SiMe2)2 exhibited non-enhanced emission.
authors: Department of Applied Chemistry, Okayama University of Science, Ridai-cho, Okayama 700-0005, Japan.
authors: Guang
authors: G
authors: Shao
authors: Akihiro
authors: A
authors: Orita
authors: Koji
authors: K
authors: Nishijima
authors: Kanako
authors: K
authors: Ishimaru
authors: Makoto
authors: M
authors: Takezaki
authors: Kan
authors: K
authors: Wakamatsu
authors: Rolf
authors: R
authors: Gleiter
authors: Junzo
authors: J
authors: Otera
mesh_terms: D000480:Alkynes / Q000138:chemical synthesis* / Q000737:chemistry*; D049449:Luminescence; D008958:Models, Molecular; D008968:Molecular Conformation; D012821:Silanes / Q000138:chemical synthesis* / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry; D013056:Spectrophotometry, Ultraviolet; D013141:Spiro Compounds / Q000737:chemistry*
chemical_list: D000480:Alkynes; D012821:Silanes; D013141:Spiro Compounds