Lewis acid–base adducts of Al(N(C6F5)2)3 and Ga(N(C6F5)2)3 – structural features and dissociation enthalpies

Abstract

Herein we present the molecular structures of six neutral Lewis acid–base adducts of the Lewis superacid Al(N(C₆F₅)₂)₃ and its higher homolog Ga(N(C₆F₅)₂)₃ with the electron pair donors MeCN, CNtBu, THF and PMe₃. 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.