Structures, optical properties, and DFT investigation of disilane-bridged σ‒π frameworks

Introduction of Si‒Si σ bond into π-conjugated compounds expands the conjugated system through σ‒π interaction. In this work, disilane-bridged cyclic and linear σ‒π frameworks were synthesized by Pd-mediated coupling reaction between hydrosilane and 1,4-diiodobenzene. Their molecular structures were confirmed by NMR spectroscopy, mass spectrometry, and single-crystal X-ray diffraction analysis. The photophysical properties in n-hexane and in the crystalline state were investigated and theoretical calculations were carried out for additional evaluation. We considered cyclic and linear σ‒π conjugation evidenced in this study.