Annulated 1,4-Disilabenzene-1,4-diide and Dihydrogen Splitting

Area of Science:

• Organosilicon Chemistry
• Main Group Chemistry
• Carbene Chemistry

Background:

• Isolation of silicon analogues of phenyl anions is challenging due to high reactivity and silylene character.
• Weak C-Si π-interactions limit the stability of analogous anionic silicon compounds.

Purpose of the Study:

• To report the synthesis and characterization of the first annulated 1,4-disilabenzene-1,4-diide.
• To investigate the electronic structure and reactivity of this novel silicon compound.

Main Methods:

• Synthesis via KC8 reduction of Si(IV) chloride and cyclic bis-chlorosilylene precursors.
• Characterization using X-ray diffraction and quantum chemical calculations.
• Reactivity studies involving dihydrogen, diphenylacetylene, elemental sulfur, and iron carbonyls.

Main Results:

• Successful synthesis of the 1,4-disilabenzene-1,4-diide compound [(ADC)Si]2 (5) featuring two-coordinated Si(I) atoms.
• Compound 5 exhibits a 6π-electron delocalized system with 15% diradical character.
• Demonstrated reactivity of 5 with H2, PhC≡CPh, S8, and Fe2(CO)9 to form novel silicon-containing compounds.

Conclusions:

• The first annulated 1,4-disilabenzene-1,4-diide has been synthesized and characterized.
• The compound displays unique diradical reactivity, enabling diverse chemical transformations.
• This work expands the scope of stable low-valent silicon compounds and their applications.