Frustrated Lewis Pairs Based on Carbon⋅⋅⋅Carbon⁺ Tetrel Bonds: A DFT Study

The ability of Triangulenium (TA⁺ ) compounds to form Frustrated Lewis Pairs (FLPs) with N-HeteroCycle Carbenes (NHCs) is analysed in this manuscript at the PBE0-D3/def2-TZVP level of theory. We have used six TA⁺ -based moieties, three presenting similar bridging groups (O (trioxo), -CH₂ (triaryl) and -NH (triaza)) and another three mixing, O, -CH₂ and NH moieties. In addition, several aryl-substituted NHCs have been used as electron donor moieties to undergo carbon⋅⋅⋅carbon⁺ tetrel bonds with the TA⁺ derivatives. More precisely, -Me,-iPr, -tBu and -Ph groups were used. Finally, we have used Bader's quantum theory of "atoms in molecules" (QTAIM) and Natural Bonding Analysis (NBO) to characterize the carbon⋅⋅⋅carbon⁺ tetrel bonds described herein. We expect the results gathered herein will be useful for further exploitation of carbon⋅⋅⋅carbon⁺ bonds in the formation of FLPs as well as to expand the current knowledge of tetrel bonds to the fields of synthetic chemistry and catalysis.