Lewis acid-base adducts of Al(N(C 6 F 5 ) 2 ) 3 and Ga(N(C 6 F 5 ) 2 ) 3 - structural features and dissociation enthalpies.

Herein we present the molecular structures of six neutral Lewis acid-base adducts of the Lewis superacid Al(N(C 6 F 5 ) 2 ) 3 and its higher homolog Ga(N(C 6 F 5 ) 2 ) 3 with the electron pair donors MeCN, CN t Bu, THF and PMe 3 . The crystal structures reveal crucial structural changes compared to the free Lewis acids as a consequence of the adduct formation. Furthermore, we calculated the corresponding dissociation enthalpies of the adducts which lie between 69 and 141 kJ mol -1 and are therefore considerably lower compared to the values for the formation of the anionic fluoride or chloride metallates.