Tadahiro Matsuno

Synthesis, Characterization, and Crystal Structure of Cyclotrisilene: A Three‐Membered Ring Compound with a Si−Si Double Bond

Red-orange crystals of cyclotrisilene 3 were obtained by the reaction of the dibromotrisilane 1 and the tribromodisilane 2 with sodium in toluene [Eq. (1)]. The X-ray crystal structure of 3 shows that the three-membered ring is almost an isosceles triangle and has a twisted Si-Si double bond with a length of 2.138(2) Å.

Synthese, Charakterisierung und Kristallstruktur von Cyclotrisilen: ein dreigliedriger Ring mit einer Si-Si-Doppelbindung

Rotorangefarbene Kristalle von Cyclotrisilen 3 wurden durch Umsetzung von Dibromtrisilan 1 und Tribromdisilan 2 mit Natrium in Toluol erhalten [Gl. (1)]. Die Kristallstrukturanalyse von 3 ergab, das der dreigliedrige Ring ein nahezu gleichschenkeliges Dreieck ist und eine verdrillte Si-Si-Doppelbindung mit einer Lange von 2.138(2) A aufweist.

Photochemical isomerization of 1,2,5-trisilabicyclo[3.2.0]hepta-3,6-diene to 1,4,7-trisilabicyclo[2.2.1]hepta-2,5-diene.

Upon irradiation of a benzene-d6 solution of 1,2,2,5-tetrakis[di-tert-butyl(methyl)silyl]-4,7-diaryl- 1,2,5-trisilabicyclo-[3.2.0]hepta-3,6-diene [1a: aryl = phenyl, b: aryl = 3,5-bis-(trimethylsilyl)phenyl], 1,4,7,7-tetrakis[di-tert-butyl-(methyl)silyl]-2,5-diaryl-1,4,7- trisilabicyclo[2.2.1]hepta-2,5-diene (2a,b) was formed via skeletal rearrangement.

Reaction of cyclotrisilene with phenylacetylene: an unusual product with a bicyclo[3.2.0]hepta-3,6-diene skeleton

Cyclotrisilene, (tBu2MeSi)4Si3, was reacted with phenylacetylene to produce an unusual 1,2,5-trisilabicyclo[3.2.0]hepta-3,6-diene derivative, whose structure was determined by NMR spectroscopy and X-ray crystallography; a mechanism for its formation is proposed.