Possible C-F bond activation by B(C6F5)3/lutidine and Al(C6F5)3/lutidine frustrated Lewis pair: an in silico study

Abstract

The activation of the C-F bond in 1-fluorobutane, 1, 1-difluorobutane and 1, 1, 1-trifluorobutane by some frustrated Lewis pair (FLP) has been assessed by DFT based computational study. The FLPs are constructed from lutidine Lewis base in association with either B(C6F5)3 or Al(C6F5)3. Thermodynamics and kinetics of the reactions are studied, which reveals the concerning bond activation mediated by the Al(C6F5)3/lutidine FLP is more favourable than the analogous reactions mediated by the B(C6F5)3/lutidine pair. Therefore, the Al(C6F5)3 acid is superior to the B(C6F5)3 acid to construct an effective FLP for some unusual bond activation. The EDA-NOCV study together with the WBI calculation reveals the C-F bond activation in the studied systems takes place by the cooperative action of the FLP partners. The activation strain model reveals the strain energy of the reactants to reach the transition state (TS) rather than the interaction energy at the TS is the decisive factor to the TS barrier height of the concerned reactions.