Hydroalumination of 1,8-Diethynylanthracenes–Al-based Bis-Lewis-Acids and their Isomerization and Complexation Behavior

1,8-Substituted anthracene derivatives−monomers and photo-dimers−bearing alkynyl units were treated with the bulky aluminum hydride [(SiMe3)2HC]2AlH in hydroalumination reactions in order to investigate the influence of the substituents on the spacing between the alkynyl units. While 1,8-bis­[(trimethylsilyl)­ethynyl]­anthracene only resulted in the mono-hydroalumination product, 1,8-diethynylanthracene and its photo-dimer afforded the products of twofold hydroalumination. In the case of 1,8-diethynylanthracene, the product underwent a cis/trans-isomerization of one of the newly formed CC bonds. This process was examined via quantum-chemical calculations. The twofold hydroaluminated syn-photo-dimer of 1,8-diethynylanthracene was treated with various donor molecules to gain insights into its host–guest chemistry.