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Density functional theory computations and block-localized wavefunction analyses for 57 hydrogen-bonded base pairs document excellent linear correlation between the gas-phase association energies and the degree of aromaticity gain of paired bases ( r = 0.949), challenging prevailing views of factors that underlie the proposed electronic complementarity of A·T(U) and G·C base pairs. Base pairing interactions can polarize the π-electrons of interacting bases to increase (or decrease) cyclic 4 n + 2π electron delocalization, resulting in aromaticity gain (or loss) in the paired bases, and become strengthened (or weakened). The potential implications of this reciprocal relationship for improving nucleic acid force-fields and for designing robust unnatural base pairs are discussed.
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On the reciprocal relationship between σ-hole bonding and (anti)aromaticity gain in ketocyclopolyenes
σ-Hole bonding interactions ( e.g. , tetrel, pnictogen, chalcogen, and halogen bonding) can polarize π-electrons to enhance cyclic [4 n ] π-electron delocalization ( i.e. , antiaromaticity gain) or cyclic [4 n + 2] π-electron delocalization ( i.e. , aromaticity gain). Examples based on the ketocyclopolyenes: cyclopentadienone, tropone, and planar cyclononatetraenone are presented. Recognizing this relationship has implications, for example, for tuning the electronic properties of fulvene-based π-conjugated systems such as 9-fluorenone.
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- Award ID(s):
- 1751370
- PAR ID:
- 10213904
- Date Published:
- Journal Name:
- Organic & Biomolecular Chemistry
- Volume:
- 18
- Issue:
- 27
- ISSN:
- 1477-0520
- Page Range / eLocation ID:
- 5125 to 5129
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D0OB01076F
