Highly selective addition of cyclosilanes to alkynes enabling new conjugated materials

Abstract

Main group organometallic compounds can exhibit unusual optical properties arising from hybrid σ,π-conjugation. While linear silanes are extensively studied, the shortage of methods for the controlled synthesis of well-defined cyclic...

Synthesis and Ring-Opening Metathesis Polymerization of a Strained trans-Silacycloheptene and Single-Molecule Mechanics of Its Polymer

“…Oligosilanes, compromising consecutive Si–Si bonds, have not previously been investigated in ROMP or ADMET. The Si–Si bond is sensitive to cleavage by late transition metals (e.g., Rh, Pd, Pt), , which may contribute to the lack of prior investigation of oligosilyl monomers.…”

Conjugation in Isomeric Cyclosilane Thioethers

“…Significant evidence of strain or unfavorable steric interactions was not obvious from the crystal structure, which showed a chairlike cyclosilane with unremarkable bond angles (102.1–115.1°) and bond distances (S–Si = 2.16 Å) for silyl thioethers. Full substitution of all Si–H bonds was notable in comparison to the Ru-catalyzed hydrosilation reaction between 1,4Si 6 and alkynes, which yielded the difunctionalized product exclusively …”

“…Full substitution of all Si−H bonds was notable in comparison to the Ru-catalyzed hydrosilation reaction between 1,4Si 6 and alkynes, which yielded the difunctionalized product exclusively. 9 Several other arylthiols were examined. Both electron-poor and electron-rich arylthiols reacted rapidly with 1,4Si 6 at room temperature (Table 1, entry 2) or 60 °C (Table 1, entry 3), and complete substitution of all Si−H bonds was again observed by both NMR (Figure 2) and IR spectroscopy (Figure S1) although trace quantities of a trifunctionalized intermediate could be detected for 1c (see the Supporting Information).…”

“…Since the discovery in the 1960s that permethylcyclosilanes exhibit longer-wavelength absorption spectra than cycloalkanes and form stable radical anions, interest in the synthesis of increasingly complex cyclosilanes has only grown . Prismatic solids , and polycyclic silanes have shed light on the impact of strain and curvature on σ-conjugation, while we have investigated the synthesis of stereochemically defined cyclosilanes. − An interest in the influence of heteroatomic substitution on optoelectronic properties has inspired work on boron- − and nitrogen-containing cyclosilanes. , Herein, we report the synthesis of cyclosilane thioethers via chemoselective dehydrocoupling of partially hydrogenated cyclosilanes and arylthiols and examine the effect of structural isomerism on conjugation. Density functional theory (DFT) calculations were used to elucidate potential mechanisms underlying experimental observations.…”

Electrochemical logic to synthesize disilanes and oligosilanes from chlorosilanes

“…Chlorogermane was also found to be a suitable substrate, providing digermane A7 in 80% yield. Importantly, we successfully synthesized 4-fluorophenyl-and 2thiophenyl-substituted disilanes (A8 and A9) from their respect chlorosilanes, thus introducing useful functional groups that could help tune the electronic and conductance properties of the silanes and provide handles for further functionalization 48 . We also attempted the homocoupling of ethoxychlorosilane (product A10), although only oxidized siloxane [(EtO)3Si]2O was isolated (see Supplementary Information Section 11).…”