A variety of functional aryl-and heteroarylchlorosilanes were prepared by electrochemical reduction of halothiophenes, halofurans, halopyridines, and substituted aryl halides in the presence of a large excess of commercial organodi-or trichlorosilanes using an undivided cell, a sacrificial Mg or Al anode, a constant current density, and tetrabutylammonium bromide as the supporting electrolyte. New structures are described, and some examples of the use of these more elaborate chlorosilanes are given, particularly as interesting precursors for the preparation of polarized D-A and D-D organosilicon models.

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The easy control of the electrochemical parameters involved in the intensiostatic sacrificial anode technique was applied to the stepwise synthesis of silanylene-2,5-thiophenylene backbones with high selectivity and versatility not accessible by purely chemical routes. 2,5-Bis(chlorodiorganosilyl)thiophenes and related linear poly[2,5-(silanylene)thiophene] oligomers with one to three silicon atoms were synthesized by electrochemical reduction of 2,5-dibromo- or 2,5-dichlorothiophene in the presence of a diorganodichlorosilane.

A new series of oligomers for nonlinear optics (NLO), the thiophene−dimethylsilyl co-oligomers, (TSi) n −T with n = 1−3, have been synthesized in order to combine third-order NLO response and transparency in the visible region. Stationary-state absorption spectra, fluorescence spectra, and time-resolved absorption (picosecond) have been carried out. In sharp contrast with oligothiophenes, the absorption spectra of (TSi) n −T are not red-shifted as n increases, but as for short oligothiophenes their quantum yield of fluorescence is low because of the competitive triplet-state formation and their emission wavelength range is remarkably solvent-independent. These data show slight increase of the dipole moment between the S0 ground state and the S1 excited state, in agreement with theoretical calculations (ZINDO method). Fast intersystem crossing is observed between singlet and triplet states and S1 → S n and T1 → T n spectra have been measured. Optical nonlinearity (γ) of the excited state has been measured and compared to the terthiophene. The large molecular second hyperpolarizability of the silyl derivatives associated with their interesting transparency properties shows that such oligomers may be considered, in the excited state, as promising molecules for nonlinear applications.