Investigation on reactivity of non-classical carbenes with sterically hindered Lewis acid, B(C6F5)3 under inert and open conditions

Reactions of B(C6F5)(3) with abnormal N-heterocyclic carbene (aNHC), L1 and cyclic (alkyl)(amino) carbene (cAAC), L2 in the presence of moisture as well as in its absence, have been investigated in toluene. Reaction of aNHC with 1 equivalent of B(C6F5)(3) under inert condition produced classical Lewis acid-base adduct, [L1.B(C6F5)(3)], 1. Further, probing the same reaction with cyclic (alkyl)(amino) carbene (cAAC), having different electronic property, led to the isolation of [L2.B(C6F5)(3)], 2 under inert condition. Interestingly, reaction of aNHC or cAAC with 1 equivalent of B(C6F5)(3) in the presence of moisture resulted in water splitting leading to the formation of [L1-H][(OH)B(C6F5)(3)], 3 and [L2-H][(OH)B(C6F5)(3), 4. All these compounds (1-4) were characterized in solution by H-1, C-13, F-19 and B-11 NMR spectroscopy. Additionally, the solid-state structures were unambiguously established by crystallographic analysis of compounds 1-4.