Lewis Acid–Base Adducts of 1-Mesityl- and 1-Chloro-2,3,4,5-tetraphenylborole

Electron-deficient borole compounds exhibit a pronounced Lewis acidity that is enhanced due to their antiaromatic character so that even weak donors datively coordinate to form Lewis acid–base adducts. This contribution presents the synthesis and structural characterization of Lewis acid–base adducts formed by the reaction of 1-mesityl-2,3,4,5-tetraphenylborole and 4-picoline as well as 1-chloro-2,3,4,5-tetraphenylborole with various donors. The new compounds are characterized by means of multinuclear NMR spectroscopy and single-crystal X-ray diffraction techniques and compared to related systems.