A zwitterionic disilanylium from an unsymmetrical disilene

The reaction of PhC(N t Bu) 2 SiSi(SiMe 3 ) 3 ( 1 ) with Me 3 SiCH 2 Cl afforded an unsymmetrical sp 2 -sp 3 disilene, 2 , with concomitant elimination of Me 3 SiCl. The analogous reaction with PhC(N t Bu) 2 SiCl resulted in the oxidative addition of the C-Cl bond at the Si( ii ) atom ( 3 ). The reactions of 2 with sulfur and selenium led to compounds with Si&z.dbd;E (E&z.dbd;S ( 4 ) and Se ( 5 )) double bonds. Tellurium reacted differently with 2 and furnished a zwitterionic compound, 6 . The reaction of PhC(N t Bu) 2 SiSi(SiMe 3 ) 3 ( 1 ) with Me 3 SiCH 2 Cl afforded an unsymmetrical sp 2 -sp 3 disilene, 2 , which underwent divergent reactivities with chalcogens.