Periodic Reporting for period 1 - ALLOWE (Highly Reactive Low-valent Aluminium Complexes and their Application in Synthesis and Catalysis)
Okres sprawozdawczy: 2021-06-01 do 2022-11-30
The overall aim of this project is the design and exploration of neutral low-valent aluminium compounds stabilized by N-heterocyclic carbenes. With novel alumylenes and dialumenes in hand, investigation into their structural and electronic nature will be undertaken through a combined experimental and computational approach. Finally, investigation into their reactivity towards small molecule activation and catalysis as well as their coordination chemistry will also be explored.
Establishment of low-valent aluminium compounds (alumylenes and dialumenes) and their applications in bond activations, catalysis and coordination chemistry is the desired outcome of this proposal. The success of this research plan would be a significant milestone in the field of organometallic and main group chemistry. In a practical sense, chemical transformations with the most abundant metal, namely, aluminium as catalyst would potentially reduce the cost of chemical production, generate little waste and even allow access to novel small organic molecules and materials. Investigations into the highly reactive ambiphilic aluminium complexes will afford a wealth of brand-new stoichiometric and catalytic reactions. The utilization of low-valent aluminium complexes enables the direct preparation of divergent novel organoaluminium compounds through the small molecule activations or coordination to transition metals. Therefore, development of the chemistry of low-valent aluminium compounds can be the key concept for making of the next generation of sustainable aluminium-based applications.
As described in the Annex I, Part B, we have conducted the reactivity studies of these complexes and found that isolation of diverse molecular aluminium sulfides demonstrate is achievable by the reaction of corresponding aluminium dihydrides with various sulfer reagents.
In addition, reactions towards elemental chalcogens (sulfur, selenium and tellurium) afforded the expected compounds, so-called, aluminium chacogenides. In fact, compound with the terminal aluminium telluride double bond has successfully isolated. Interestingly this aluminium telluride complex does react with carbon monoxide and afforded intriguing complex with carbon tellurium double bond.
Meanwhile, we have also developed the reactivity of dialumenes towards various small molecules. Intriguing activation products from the reaction of NHC-coordinate dialumenes with white phosphorus or pyridine have been isolated.
Introduction of four bulky silly groups (tBu2MeSi) into the aluminium centre allowed us to isolate dialane(4) (tBu2MeSi)2Al-Al(SiMetBu2)2.
Reactivity of this tetrasilyldialane(4) is currently undergoing. In fact, two-electron reduction of this dialane(4) produced dianionic species which is presumably desired dianionic dialumenes with double bond.