Coplanar Oligo(p-phenylenedisilenylene)s Based on the Octaethyl-Substituted s-Hydrindacenyl Groups
摘要:
The silicon analogues of the oligo(p -phenylenevinylene)s (Si-OPVs) with highly planar structures have been synthesized using a newly developed ligand, the 1,1,3,3,5,5,7,7-octaethyl-s -hydrindacen-4-yl (Eind) group. Their X-ray crystal structures and spectroscopic data demonstrate that the pi-conjugation effectively extends over the Si-OPV framework. Notably, tetrasiladistyrylbenzene exhibits an orange fluorescence even at room temperature both in solution and in the solid state, which is attributable to the effective extension of conjugation. To the best of our knowledge, the tetrasiladistyrylbenzene is the first emissive Si=Si derivative even at room temperature.
pi-Conjugated phosphasilenes with a variety of aryl substituents on the silicon atom have been synthesized by the use of a 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl (Eind) group. X-ray structural analysis shows the highly coplanar pi-framework stabilized by the perpendicularly fixed Eind groups. The strong pi-pi* absorptions have been observed, demonstrating the extension of pi-conjugation over the skeleton. The DFT calculations indicate that the LUMO involves the substantial contribution of the 3p pi*(Si- P)-2p(pi)*(carbon pi-electron system) conjugation. The electrochemical properties of the phosphasilens are also presented.