Synthesis of bi- and tetradentate poly-Lewis acids by hydroalumination of poly-alkynyl-anthracene derivatives

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 51; no. 34; pp. 12943 - 12953
• Main Authors: Aders, Niklas, Lamm, Jan-Hendrik, Beckmann, J. Louis, Neumann, Beate, Stammler, Hans-Georg, Mitzel, Norbert W
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 30.08.2022
• Subjects: Adducts; Aluminum hydrides; Anthracene; Dimers; Lewis acid; Molecular chains; NMR spectroscopy; Supramolecular compounds; Ultraviolet radiation
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/d2dt02118h

Photo-dimers of 1,5-diethynylanthracene and 1,5-bis[(trimethylsilyl)ethynyl]anthracene, obtained by UV radiation of the monomers, were treated with the bulky aluminium hydride [(SiMe 3 ) 2 HC] 2 AlH in hydroalumination reactions. Hydroalumination of the tetraethynyl-substituted anthracene photo-dimers ( syn and anti ) led to fourfold aluminium-functionalized Janus-like products with two aluminium functions on each side oriented towards the same direction. The reactions of the monomeric anthracene derivatives with [(SiMe 3 ) 2 HC] 2 AlH afforded semi-flexible bidentate Lewis acids, which are interesting building blocks for molecular chains bearing multiple Lewis-acidic functions. The aluminium-functionalized anti -photo-dimer was treated with various donor molecules to gain insight into its host-guest chemistry. All poly-Lewis acids and their adducts were characterized by X-ray diffraction experiments, multinuclear NMR spectroscopy and by elemental analyses. Two tetra-functional Lewis-acids with a large and a small "bite width" of the cavities were synthesized; the host-guest chemistry of the large bite compound was investigated regarding chelating effects.