Synthesis and Ring-Opening Reactions of 1,8-Silanonaphthalenes

Abstract

1,8-(Di-sec-butylsilano)-, 1,8-{bis[(trimethylsilyl)methyl]silano}-, and 1,8-{bis[(S)-2-methylbutyl]silano}naphthalene (1a−c) were prepared, and their ring-opening reactions were investigated. Reactions of 1a,b with methyllithium afforded products arising from the addition of methyllithium to the Si−C bond of the four-membered ring of 1a,b, followed by rearrangement of the resulting anionic species. Methanolysis of 1a gave 1-(methoxydi-sec-butylsilyl)naphthalene. Heating 1a,b in the presence of a catalytic amount of Pd(PPh3)4 gave the head-to-tail cyclic dimers. Treatment of 1a,c with lithium metal gave ring-opened oligo(silylene-1,8-naphthylenes) in good yield. The optical data of the oligomers indicated the existence of helical structural segments in the backbone. The hole-transporting properties of the oligomer obtained from 1a were examined by the performance of an EL device with the strcture of ITO/oligo(silylene-1,8-naphthylene)/Alq/Mg−Ag, which emitted green luminescence due to the Alq emission. The crystal structures of 1b and its dimer were examined by X-ray diffraction studies.