Donor-free 9,10-dihydro-9,10-dialuminaanthracenes

Area of Science:

• Organometallic Chemistry
• Main Group Chemistry
• Synthetic Chemistry

Background:

• 9,10-dihydro-9,10-dialuminaanthracenes (DAA-R2) show potential as ditopic Lewis acids.
• Synthesis of ligand-free DAA-R2 species has been challenging, limiting exploration.

Purpose of the Study:

• To develop a synthetic route to DAA-R2 compounds.
• To investigate the reactivity and structural properties of DAA-R2 dimers.
• To explore their utility in constructing complex molecular architectures.

Main Methods:

• Reaction of 1,2-(Me3Sn)2C6H4 with AlMe3 to synthesize DAA-Me2.
• Dimerization of DAA-Me2 in non-coordinating solvents and solid state.
• Treatment with AlBr3 to form DAA-Br2·(AlBr3)2 and subsequent isolation of DAA-Br2.
• Reactions of DAA-R2 dimers with mono- and ditopic Lewis bases.

Main Results:

• DAA-Me2 synthesized via a tin-mediated route with volatile SnMe4 byproduct.
• (DAA-Me2)2 and (DAA-Br2)2 dimers were characterized.
• DAA-Br2 was obtained after AlBr3 removal, which also dimerizes.
• Reaction with Lewis bases yielded trans-diadducts and triptycene-type frameworks.
• Selective Al-C bond cleavage in DAA-Br2·(AlBr3)2 produced a valuable synthon for 1,2-dideprotonated benzenes.

Conclusions:

• A viable synthetic pathway to DAA-R2 compounds was established.
• DAA-R2 dimers serve as versatile precursors for novel Lewis acid adducts and frameworks.
• The findings open avenues for utilizing DAA-R2 in coordination chemistry and materials science.