MASS-SPECTRA OF OCTASPHEROSILOXANES

The mass spectra of 14 different octasilasesquioxanes R(8)Si(8)O(12) a re presented, The well-known uniformly substituted compounds (R(8)=H-8 , Me(8) or Et(8)) were re-examined and consequently used for compariso n, The initial characterization of all the compounds examined was achi eved with H-1-NMR spectroscopy, The influence of the different substit uents (hydrogen, methyl, ethyl, ethyl phenyl and styrene) under electr on impact ionization and collision-induced dissociation conditions was examined, The compounds with hydrogen substituents demonstrated minor cage destruction, whereas the compounds with organic substituents sho wed multiple losses of the substituents but no destruction of the cage system at all, The stability of the cubic Si8O12 system seems to incr ease further with an increasing number and size of organic substituent s, The additional information gained by collision experiments was mode st. All mass spectra also contained doubly charged ions.