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Hydrogen bond–aromaticity cooperativity in self‐assembling 4‐pyridone chains
Author(s) -
Anand Megha,
Fernández Israel,
Schaefer Henry F.,
Wu Judy IChia
Publication year - 2016
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.23976
Subject(s) - aromaticity , chemistry , natural bond orbital , hydrogen bond , crystallography , 2 pyridone , delocalized electron , chemical bond , lone pair , computational chemistry , stereochemistry , molecule , density functional theory , organic chemistry
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 NH···OC 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. © 2015 Wiley Periodicals, Inc.