title: Hydrogen bond-aromaticity cooperativity in self-assembling 4-pyridone chains.
abstract: Self-assembling building blocks like the 4-pyridone can exhibit extraordinary H-bond-aromaticity coupling effects. Computed dissected nucleus independent chemical shifts (NICS(1)zz), natural bond orbital (NBO) charges, and energy decomposition analyses (EDA) for a series of hydrogen (H-) bonded 4-pyridone chains (4-py)n (n = 2 to 8) reveal that H-bonding interactions can polarize the 4-pyridone exocyclic C=O bonds and increase 4n+2 π-electron delocalization in the six-membered ring. The resulting H-bonded 4-pyridone units display enhanced π-aromatic character (both magnetically and energetically) and their corresponding N-H···O=C interactions are strengthened. These π-electron polarization effects do not depend on the relative orientations (co-planar or perpendicular) of the neighboring 4-pyridone units, but increase with the number of H-bonded units.
authors.affiliation: Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia, 30602.
authors.forename: Megha
authors.initials: M
authors.lastname: Anand
authors.affiliation: Departamento de Química Orgánica I, Facultdad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain.
authors.forename: Israel
authors.initials: I
authors.lastname: Fernández
authors.affiliation: Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia, 30602.
authors.forename: Henry F
authors.initials: HF
authors.lastname: Schaefer
authors.affiliation: Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia, 30602.
authors.forename: Judy I-Chia
authors.initials: JI
authors.lastname: Wu
keywords: aromaticity; energy decomposition analysis; hydrogen bonding; nucleus independent chemical shifts; self-assembly