Les moments dipolaires de quelques hydrocarbures polycycliques

Bergmann, Emely; Fischer, E.; Pullman, Bernard

doi:10.1051/jcp/1951480356

Cited by 14 publications

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“…4-With biphenyl-2-magnesium iodide Condensation of the Grignard reagent from 2-iodobiphenyl with cyclohexanone followed by dehydration of the product gives a 29 per cent yield of 2-(l-cyclohexenyl)biphenyl (V). Epoxidation of the hydrocarbon, followed by ring closure with hydrobromic and acetic acids, gives 1,2,3,4-tetrahydrotriphenylene (VI) in 30 per cent yield (40).…”

Section: Dehydrogenation Of Hydrotriphenylenesmentioning

confidence: 99%

The Preparation, Reactions, and Properties of Triphenylenes.

Buess¹,

Lawson²

1960

Chem. Rev.

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Section: Dehydrogenation Of Hydrotriphenylenesmentioning

confidence: 99%

The Preparation, Reactions, and Properties of Triphenylenes.

Buess¹,

Lawson²

1960

Chem. Rev.

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Simple ways to calculate the empirical resonance energies of benzenoid hydrocarbons, their derivatives, and graphite

Hakala

2009

Int. J. Quantum Chem.

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A very simple equation is presented which reproduces the empirical resonance energies of 12 different benzenoid hydrocarbons within an average of f 1.4%, a considerably better result than those obtained by the VB method ( f 11.0%) and the simple LCAO-MO methods including overlap ( f5.1%) and neglecting overlap ( f 11.8%). In the cases of the larger polyacenes (9 hydrocarbons) for which experimental values of empirical resonance energies are not available, this equation provides nearly the same results as the LCAO-MOoverlap method. A second equation is given which yields the electron delocalization energies, in units of y, of 21 benzenoid hydrocarbons within an average of fl.O%. Formulas, based on the first equation, are found for the empirical resonance energies of eight different sequences of benzenoid hydrocarbons (e.g. benzene, coronene, fie& dcdecabenzocoronene, etc.). As a check, these formulas ire used to estimate the resonance energy, per gram atom, of graphite, with satisfactory results (12 kcal versus the literature value of 10). It is then shown that the empirical resonance energies of benzenoid hydrocarbon derivatives can be determined by making use of group corrections to the calculated values of the empirical resonance energies of benzenoid hydrocarbons. The average error of the empirical resonance energies calculated by this method for 44 compounds was f0.8 kcal/mole or f 1.5%.Current ab initio methods are unsuitable for large molecules. Hopefully, the mathematics of these methods will be developed so as to make possible accurate, rapid (inexpensive !) , ab initio calculations for large molecules. Meanwhile, accurate and quickly obtained quantitative data for large molecules are needed by organic chemists, quantum biologists, and other workers. Consequently, empirical and semiempirical methods are still very necessary in quantum mechanics. In the present paper, an accurate, yet very simple, empirical formula for calculating the resonance energies of benzenoid hydrocarbons, and a procedure for correcting these to the resonance energies of aromatic compounds, are. presented.The exact physical significance and numerical values of empirical resonance energies have been disputed, but there is no question that an internally consistent collection of empirical resonance energy values is of considerable utility. In the present paper we shall adopt the most widely used value for the empirical *fiesent address:

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The polarographic reduction of conjugated hydrocarbons: VI. Comparison of Hückel's and Wheland's m.o. approximation with experimental half‐wave potentials of various alternant and non‐alternant hydrocarbons

Hoijtink

1955

Recl. Trav. Chim. Pays‐Bas

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On the basis of the results reported in the foregoing papers IV and V and the data obtained by Bergmant) from the reduction of various aromatic hydrocarbons in ethylene glycol mono-methyl ether Maccoll's relationship between the experimental halfwave potential and the root of the m.0. secular equation corresponding to the lowest non-occupied n-electronic level has been investigated in more detail. It is shown that the half-wave potentials of 38 alternant and non-alternant hydrocarbons being reduced according to the mechanism inferred in paper IV satisfy the relationship: = a.y -0.85 Volt The mean value of the resonance parameter y in e.v. for various experimental conditions becomes: 96% dioxan-water -2 27 f 0 076 Cellosolve b) -262 f 0.066 -2.30 f 0.076 -2.54 f 0.090 a) 75% dioxan-water -250 f 0.092 -2.22 f 0.090 a) twice the standard deviation from mean. b) c.f. note c) of table I. The half-wave potentials of the univalent anions of various conjugated hydrocarbons determined by the equilibrium R + e % R in % yo dioxan-water and the half-wave potential of the radical triphenylmethyl fit the relationship: 1 . ) G. J. Hot%& and J. van Schooten, Rec. trav. chim. 71, 1089 (1952); b) ibid.

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Les moments dipolaires de quelques hydrocarbures polycycliques

Cited by 14 publications

References 0 publications

The Preparation, Reactions, and Properties of Triphenylenes.

The Preparation, Reactions, and Properties of Triphenylenes.

Simple ways to calculate the empirical resonance energies of benzenoid hydrocarbons, their derivatives, and graphite

The polarographic reduction of conjugated hydrocarbons: VI. Comparison of Hückel's and Wheland's m.o. approximation with experimental half‐wave potentials of various alternant and non‐alternant hydrocarbons

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