Synthesis and Functionalization of a 1,4-Bis(trimethylsilyl)tetrasila-1,3-diene through the Selective Cleavage of Si(sp²)–Si(sp³) Bonds under Mild Reaction Conditions

Although the oxidative coupling of disilenides, i.e., the disilicon analogues of vinyl anions, represents a promising route to extend the conjugation between SiSi double bonds, previously reported synthetic routes to disilenides involve strongly reducing conditions. Herein, we report a novel synthetic route to disilenides from stable disilenes via the selective cleavage of Si­(sp²)–Si­(sp³) bonds under milder reaction conditions. Using this method, a 1,4-bis­(trimethylsilyl)­tetrasila-1,3-diene (<b>5</b>) was synthesized from the corresponding silyl-substituted disilene. Moreover, Et₃Si-substituted tetrasila-1,3-diene <b>7</b> was synthesized via tetrasila-1,3-dien-1-ide <b>6</b>, which is the first example of a functionalized tetrasila-1,3-diene

Functionalized Ruthenium Dialkynyl Complexes with High Second-Order Nonlinear Optical Properties and Good Potential as Dye Sensitizers for Solar Cells

Various dipolar π-delocalized Ru­(II) dialkynyl complexes were prepared and characterized. Their second-order nonlinear optical (NLO) properties were investigated by the electric-field-induced second harmonic generation (EFISH) technique working in CH₂Cl₂ solution with an incident wavelength of 1907 nm, whereas the dipole moments were determined by density functional theory (DFT) calculations. All the investigated complexes are characterized by a negative value of μβ_1.907 EFISH, in agreement with a negative value of Δμ_eg (difference of the dipole moment in the excited and ground state) upon excitation. Their second-order NLO response can be easily modulated by the nature of the alkynyl substituents. Besides, the most promising “push–pull” ruthenium diacetylide complex, adequately functionalized for anchoring to TiO₂, was tested as photosensitizer in dye-sensitized solar cells (DSSCs)