TRANSITION-METAL-CATALYZED SILYLENE EXPULSION FROM, AND OR REARRANGEMENT OF, OLIGOSILANES

Photochemical treatment of HSiMe2SiMe2R (R = Me) with a catalytic amou nt of (eta5-C5H5)Fe(CO)2-SiMe3, (1) led to the high-yield formation of Me2Si, trapped efficiently with HSi(SiMe3)3. The use of (eta5-C5H5)Fe (CO)(PPh3)SiMe3 (2) as catalyst in a thermal reaction does not produce silylene but causes isomerization of the disilane (R = Ph). Photochem ical treatment of HSiMe2SiMe2SiMe2SiMe3 with a catalytic amount of 1 i nitially produced HSi(SiMe3)3 with further transformation to HSiMe2Si( SiMe3)3 via silylene insertion. However, thermal catalysis using 2 yie lded only HSi-(SiMe3)3. Both thermal and photochemical catalytic proce sses proceed via equilibrating Fe silyl silylene intermediates.