A [10]Annulene isomer may be aromatic, after all

Journal Article · Wed Feb 01 00:00:00 EST 1995 · Journal of the American Chemical Society; (United States)

DOI:https://doi.org/10.1021/ja00109a021· OSTI ID:6492728

Sulzbach, H M; Schleyer, P.R. von ^[1]; Jiao, H ^[2]; Xie, Y; Schaefer, III, H F ^[3]

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1. Univ. of Georgia, Athens, GA (United States) Univ. Erlangen-Nuernberg (Germany)
2. Univ. Erlangen-Nuernberg (Germany)
3. Univ. of Georgia, Athens, GA (United States)

Despite its adherence to Huckel's rule, $LB 10$RB annulene is thought to prefer nonaromatic, nonplanar structures. This seemingly reasonable conclusion is based on experimental studies carried out a quarter century ago, but the detailed nature of the [10]annulene isomers has not been fully elucidated. A new, nearly planar aromatic monotrans [10]annulene configuration has now been characterized at the second-order perturbation (MP2) and density functional (B3LYP) levels of theory. The structure, with a symmetry plane that bisects the molecule, is not a stationary point at uncorrelated levels, but it is the most stable [10]annulene isomer at MP2(fc)/DZd and at higher levels. The inner hydrogen is only bent out of the approximate carbon plane by about 20[degree]. The estimated aromatic stabilization energy (17.7 kcal/mol, after correction for strain), the diamagnetic susceptibility exaltation ([Lambda] = -66.9 ppm cgs, [Lambda][sub Naphtalene] = -28.2), and the upfield NMR chemical shift of the inner hydrogen ([delta] = -6.1 ppm) confirm the aromaticity of this new C[sub s] [10]annulene conformation. 23 refs., 3 figs., 5 tabs.

• DOE Contract Number: FG05-94ER14428
• OSTI ID: 6492728
• Journal Information: Journal of the American Chemical Society; (United States), Vol. 117:4; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
AROMATICS
CHEMICAL SHIFT
DIAMAGNETISM
NMR SPECTRA
ISOMERS
MAGNETIC SUSCEPTIBILITY
MOLECULAR STRUCTURE
NUMERICAL DATA
PERTURBATION THEORY
STRAINS
DATA
INFORMATION
MAGNETIC PROPERTIES
MAGNETISM
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
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400201* - Chemical & Physicochemical Properties
400102 - Chemical & Spectral Procedures