AMHB: (Anti)aromaticity-Modulated Hydrogen Bonding.

This in silico survey shows that changes in the (anti)aromatic character of π-conjugated heterocycles can be used to fine-tune their hydrogen (H-)bond strengths. Upon H-bonding dimerization, the π-electrons of these rings can be polarized to reinforce or disrupt their (anti)aromatic π-conjugated circuits (πCCs) and stabilize or destabilize the resulting H-bonded complexes. H-bonding interactions that enhance aromaticity or relieve antiaromaticity are fortified, whereas those that intensify antiaromaticity or disrupt aromaticity are weakened, relative to analogues lacking full π-circuits. Computed dissected nucleus-independent chemical shifts, NICS(1)zz, reveal a uniform pattern and document changes in the magnetic (anti)aromatic character of the heterocycles considered. Recognition of this (anti)aromaticity-modulated H-bonding (AMHB) phenomenon offers insights into a range of fields from organocatalysis and self-assembly to pharmaceutical chemistry and molecular biology.