Synthesis and Structure of a Heavier Congener of Biphenyl: 1,1′-Disila-4,4′-biphenyl

The 1,1'-disila-4,4'-biphenyl species 1, the first molecule bearing directly connected two silaaromatic rings, was synthesized and characterized by its spectroscopic and X-ray crystallographic data. The UV-vis spectrum of 1 showed not only a red shift but also a 6-fold increase in absorbance of the longest absorption maximum in comparison with those of Tbt-substituted silabenzene, indicating that the concept of conjugation through the single bond connecting two aromatic rings is applicable even in silaaromatic systems.