Amine Superbases Stabilized by Extended Hydrogen Bond Networks

Extended hydrogen-bonding networks as a mechanism for creating superbases is explored through six different amine scaffolds: linear acenes, cyclohexane, decalin, triptycene, adamantane, and [2.2]paracyclophane. The gas-phase proton affinities of 21 different potential superbases were computed at the omega B97X-D/6-311+G(2d,p) level. This method was benchmarked against the experimental proton affinities of 4-4 nitrogen bases. Extended hydrogen-bonding networks, including second- and third-layer hydrogen bonding, led to bases with proton affinities 20 kcal mol(-1) greater than that of bis(dimethylamino)naphthalene. The strongest bases are the decalin base 25 and the adamantane base 31.