Organosilicon chalcogenides with trisilane units — adamantanes and noradamantanes

1,1,3,3-Tetrachlorotetramethyltrisilane (1b) has been prepared from Ph2MeSiCl and Me2SiCl2 via Ph2MeSiSiMe2SiMePh2 (1a). Reaction of 1b with Li2E (E=S, Se) furnishes the new tricyclic organosilicon chalcogenides (Me2Si)2(MeSi)4E4 (E=S (2a), Se (2b)) with adamantane structures. If a mixture of 1b and Cl2MeSiSiMeCl2 is reacted with H2S/NEt3, (Me2Si)(MeSi)4S4 (3a), a noradamantane with a trisilane and a disilane unit is formed. The molecular structures of 2a and 3a are reported. All new compounds are characterized by NMR spectroscopy (1H, 13C, 29Si, 77Se).