Nitrogen fixation, (electro)reduction and functionalization based on silicon systems

• Applicant: Professor Dr. Matthias Drieß
• Subject Area: Inorganic Molecular Chemistry - Synthesis and Characterisation
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 535153786

Nitrogen fixation and reduction based on nonmetallic and non-toxic silicon, the second most abundant element of the Earth’s crust, is currently unknown. The development of a molecular silicon-based system capable of direct conversion of nitrogen towards a value-added chain under mild reaction conditions is challenging and could elevate silicon chemistry to the realm of nitrogen economy. We will target the first series of bis(silylenes) with reducable cooperative divalent silicon atoms which engender molecular and electrochemical dinitrogen fixation, reduction and functionalization under mild reaction conditions. The unique feature of these novel bis(silylenes) is that each Si(II) atom is coordinated to a redox-non innocent chelating phenalenyl (PLY) ligand that can reversibly accept and store extra electrons in nonbonding orbitals which facilitate electron-transfer to N2. Moreover, the bis(PLY-silylene) groups are attached to different molecular spacers including those bearing a neutral Si(II) Lewis acid or polycationic Si(IV) superacid site that favor end-on N2Si fixation prior to N2 reduction. The redox-non innocent and reversible electron-storage capability of PLY is also key to achieve covalent attachment of the bis(PLY-silylenes) on reduced graphene oxide (rGO); the latter composite material will be grafted on graphite electrodes for a electrochemical cell to engender N2 reduction and subsequent C-N functionalization of the reduced N species with masked organic electrophiles R+ present in tetraorganoammonium (R4N+)-containing electrolytes.

• DFG Programme: Reinhart Koselleck Projects