SYNTHESIS, STRUCTURE AND PHOTOLUMINESCENCE OF 1,2-DISILA-ACENAPHTHENESI2C10H10 AND 1,2-DIARYLDISILANE REFERENCE COMPOUNDS

For the synthesis of the diaryldisilanes Ar-SiH2SiH2-Ar (la, Ar = phen yl; 1b, Ar = p-tolyl; 1c, Ar = mesityl; 1d, Ar = p-anisyl) two conveni ent preparative routes are reported. The crystal structures of 1c and 1d have been determined in Xray diffraction studies; the disilanes hav e a staggered transconformation with a crystallographically imposed ce nter of inversion. For 1a-d no photoluminescence phenomena can be obse rved. 1,2-Disila-acenaphthene (2) is synthesized in acceptable yield b y treatment of 1,8-dilithionaphthalene with 1 equivalent of 1,2-bis[(( trifluoromethyl)sulfonyl)oxy]disilane Tf-SiH2SiH2-Tf. The crystal stru cture of 2 has also been determined by X-ray diffraction. The molecule has no crystallographically imposed symmetry but closely follows the symmetry elements of point group C-2v. Solutions of 2 exhibit intense fluorescence in the near UV region at room temperature. The fluorescen ce spectra are discussed in comparison with data on acenaphthene and n aphthalene.