Hydrogen bonding interactions play important roles in many aspects of chemistry, e.g., DNA base pairing, enzyme catalysis, and the design of supramolecular materials, and it is of great interest for chemists to control and predict their strengths. In contrast to the secondary electrostatic interaction (SEI) model proposed by Jorgensen et al., for understanding the associations of multipoint hydrogen-bonded arrays, we propose the aromaticity-modulated hydrogen bonding (AMHB) concept and show that aromaticity can be used to tune the strengths of intermolecular hydrogen bonds. Our computations, based on the blocklocalized wavefunction method (BLW) and the nucleus-independent chemical shifts method (NICS) for more than 50 hydrogen-bonded arrays, show that, the inherent association energies of multipoint hydrogenbonded arrays do not follow expectations based on the SEI model but follow predictions based on AMHB. Hydrogen bonding interactions that enhance/reduce the aromatic characters of multipoint hydrogen bonded arrays are strengthened/weakened. Excellent correlation was obtained between the π -electron delocalization energies of multipoint hydrogen-bonded arrays and their computed gas-phase association free energies, demonstrating that the π -conjugation patterns of arrays (i.e., their aromatic character) are good predictors of their association strengths.

Aromaticity-modulated hydrogen bonding (AMHB)

255th National Meeting (2018)

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