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

Journal Article · Wed Feb 01 04:00:00 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), Journal Name: Journal of the American Chemical Society; (United States) Vol. 117:4; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

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