The mass spectra of 14 different octasilasesquioxanes R$idOl2 are presented. The well-known uniformly substituted compounds (R8=H8, Me, or EG) were reexamined and consequently used for comparison. The initial characterization of all the compounds examined was achieved with 'β¬I-NMR spectroscopy. The influence of the different substituents (hydrogen, methyl, ethyl, ethyl phenyl and styrene) under electron impact ionization and collision-induced dissociation conditions was examined. The compounds with hydrogen substituents demonstrated minor cage destruction, whereas the compounds with organic substituents showed multiple losses of the substituents but no destruction of the cage system at all. The stability of the cubic Si,012 system Seem to increase further with an increasing number and size of organic substituents. The additional information gained by collision experiments was modest. All mass spectra also contained doubly charged ions.
EXPERIMENTAL
Mass spectrometry
Most of the mass spectrometry experiments were performed on a double-focusing Fisons VG ZAB 2F (Fisons-VG, Altrincham, Manchester, UK) mass spectrometer with BEconfiguration (reversed Nier-Johnson geometry). The accelerating voltage was 8 kV using a combined EIKI