Electronic Spectrum of Cyclononatetraenide

Simmons, H. E.; Chesnut, D. B.; LaLancette, E. A.

doi:10.1021/ja01083a008

Cited by 18 publications

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“…La seule Ctude consacrke i la physicochimie de ce type de composCs, et exterieure i notre laboratoire, est celle publike en 1964 par H. E. Simmons, D. B. Chesnut et E. A. Lalancette [30]. Ces auteurs ont, en effet, calculC le spectre Clectronique de l'anion cyclononatetraenyle au moyen d'une mCthode SCF-II de type Pariser-Pan et Pople.…”

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“…En dehors des travaux rCalisCs au sein de notre laboratoire [27-291 les composCs conjuguts contenant le cycle enneagonal n'ont pratiquement pas Ct C abordCs thCoriquement au moyen des mCthodes de la chimie quantique. La seule Ctude consacrke i la physicochimie de ce type de composCs, et exterieure i notre laboratoire, est celle publike en 1964 par H. E. Simmons, D. B. Chesnut et E. A. Lalancette [30]. Ces auteurs ont, en effet, calculC le spectre Clectronique de l'anion cyclononatetraenyle au moyen d'une mCthode SCF-II de type Pariser-Pan et Pople sant de comparer 2 l'experience les gtomttries fournies par MNDO pour les cinq com-pos6s pentagonaux monocycliques considCrts dans cette etude (voir Tableau 11).…”

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Etude MNDO des composes conjugues enneagonaux

Ouamerali

Gayoso

1986

Int J of Quantum Chemistry

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ResumeSelon les r6sultat.s obtenus au moyen de MNDO, apds optimisation complkte de la gkomktrie, les anions cyclononatetrwnyle et benzocyclononatetranyle, l'ennkapyrrole et I'enneathiophkne sont des composks plans a tendance aromatique. L'enneafulvkne posskde une conformation pkferentielle plane mais une structure de composk conjugut polybnique alors que I'enneafuranne et le cyclononatetraene sont des molkcules gauches. La methode de Huckel universelle (MHU), qui est une technique emphique simple, tenant compte de tous les klectrons de valence et decrivant les systkmes u au moyen d'oM localis6es, conduit aux m h e s conclusions que la mkthode MNDO. Les calculs effectuks au moyen de MNDO et MHU nous ont permis de d6crire I'ensemble des propri6tks physicochimiques des composks conjuguks enneagonawt pris en considkration.A notre connaissance, nous prksentons ici, la premikre etude tkhrique des composks conjuguks contenant le cycle k neuf membres. AbstractWe present MNLKI calculations of a series of nine-membered conjugated compounds. The geometries have been fully optimized. Cyclononatetraenyl and benzocyclononatetraenyl anions, nonapyrrol, and nonathiophene appear to be planar aromatic compounds. Following MNDO, nonafulvene has a planar prefeted conformation, but a polyenic structure, while nonafuran and cyclononatetraene are gauche molecules. The Universal Huckel Method (UHM), a simple all valence electron empirical technique which describes u systems using localized MO, gives, qualitatively, the same results as the MNDO method. The quantum calculation carried out with MNDO and UHM have been used to describe the physicochemical properties of ninemembered ring conjugated compounds under consideration. To our knowledge, we present here the f i t theoretical study dealing with nine-membered conjugated molecules.

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Etude MNDO des composes conjugues enneagonaux

Ouamerali

Gayoso

1986

Int J of Quantum Chemistry

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“…(8) J. H. Simons and K. E. Lorentzen, ibid., 74, 4746 (1952). (9) We do not mean to indicate that R+OH2~OBs is identically the same species as R+HO2CCF3-OBS but both can be represented by the general notation R* jjOBs and their relative rates of dissociation and recombination in the same solvent should be similar. Also, R+OBs may not be exactly the same species (in terms of conformation and solvation especially) when formed by proton transfer from HOBs to propene as when produced by ionization of ROBs; the differences are probably slight, however, and R'OBs from the latter source should not be any less likely to recombine than that from the former.…”

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Addition of undissociated strong acids to alkenes. "Hidden return" revealed

Shiner¹,

Dowd²

1969

J. Am. Chem. Soc.

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We wish to report observations which shed new light on the behavior of the ion pairs which are involved in the trifluoroacetolysis of secondary arenesulfonate esters.12 Isopropyl jy-bromobenzenesulfonate (ROBs) reacts in trifluoroacetic acid (TFA) at 25°to give, within the limits of nmr detection, a quantitative yield of isopropyl trifluoroacetate (ROCOCF3). The half-life based on the rate of disappearance of the nmr signal is 182 min. Neither the product yield nor the half-life is significantly different if the reaction is carried out in the presence of excess sodium trifluoroacetate. Propene is converted to ROCOCF3 relatively slowly by TFA either alone or buffered (half-life -~300 min). However, in trifluoroacetic acid, propene (0.2 M) and p-bromobenzenesulfonic acid (HOBs, 0.1 ) react within less than 1 min to produce isopropyl p-bromobenzenesulfonate apparently quantitatively. We interpret this to mean that propene and undissociated HOBs react directly to produce a "tight" ion-pair (R+OBs) which covalently combines at a rate much faster than it dissociates. Dewar and Fahey3 have argued that the cis addition of HBr to acenaphthylene in acetic acid involves formation and rapid combination of ion pairs. It is obvious that in these reactions ion-pair combination is faster than solvolysis.4

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10,10‐Bis(dimethylamino)nonafulven

Häfner

Tappe

1969

Angewandte Chemie

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Herrn Professor CI. Schopf zum 70. Geburtstag gewidmei Mit Ausnahme des Li-, Kund [(CH3)4N]-Cyclononatetraenids (I) [I] wurden bisher keine monocyclischen Derivate des hypothetischen Cyclononatetraens isoliert [21. Nonafulvenen kommt als gekreuzt konjugierten lox-Elektronensystemen und Homologen der Fulvene besonderes Interesse zu. Gleich dem Fulven-und Isobenzofulvensystem 131 sollten auch Nonafulvene durch elektronenspendende Substituenten amzexocyclischen C-Atom stabilisiert werden. Die Synthese des lO,lO-Bis(dimethylamino)nonafulvens (4) bestatigt diese Vermutung.

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Electronic Spectrum of Cyclononatetraenide

Cited by 18 publications

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Etude MNDO des composes conjugues enneagonaux

Etude MNDO des composes conjugues enneagonaux

Addition of undissociated strong acids to alkenes. "Hidden return" revealed

10,10‐Bis(dimethylamino)nonafulven

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