Naphthalenium ions

Draw Lewis structures (or a series of Lewis structures) for the intermediate ions formed by addition of N02 to naphthalene at the 1 and 2 positions (nitro-naphthalenium ions ). On this basis, are you able to anticipate which intermediate is likely to be the more stable Examine the energies of 1-nitronaphthalenium and 2-nitronaphthalenium ions to see which ion is actually more stable. Which substitution product should be favored Is this the same product anticipated by inspection of naphthalene s HOMO Is it the observed product ... 

It was also possible to prepare stable ethylene-(4-X)-naphthalenium ions 115 (X= Me, Ph, OMe) and 9,9-ethylene-(10-X)-anthracenium ions 116 (X = H, Br) under long-lived stable ion conditions114. 

SbF5-FS03H—SO2CIF-SO2F2 solution at the naphthalenium ion (31) at -90 °C... 

Fig. 2. Compilation of H NMR and A5I3C values for alkylated naphthalenium ions.

The same procedure was used to generate perfluoro-a-naphthalenium ion ... 

CH3 (3.1-3.6) and 2-CH3 (2.S-3.2 ppm). The introduction of a CH3 group to 4-position was observed to cause a down-field shift of the H signal by 0.5 ppm The spin-spin coupling constants for the protonated ring of 1-H-naphthalenium ions have the following values ... 

The influence of the position of CHj groups on the relative stability of methyl-naphthalenium ions is discussed in Sect. IV.2C. 

Ill Structure of Arenium Ions According to Physical Data Table 7. PMR Data of Methyl-substituted 1-Naphthalenium Ions... 

For the rotation hindrance of the methoxy group in 2-halogen-4-methoxybenze-nium ions see in 2-methoxy-l-naphthalenium ion The hindrance of rotation in hydroxyarenium ions was observed in 4-hydroxy-benzenium heptabromodialuminate >. In the PMR spectrum of a solution of this salt in CSj at —70 °C the Hj and Hj atoms give separate signals which coalesce when the temperature rises to —60 °C. 

Table 13. PMR Data of l-Hydroxy-2-Naphthalenium Ions and their O-Derivatives...

Table 15. PMR Data of 4-Hydroxy-1-Naphthalenium Ions and their 0-Derivatives...

Among the 2-naphthalenium ions NMR- C data are available for the 1,2,2,3,4-pentamethyl-substituted cation and for a few hydroxynaphthalenium ions... 

For p-, m- and a-fluorine-substituted ions of Iwnzyl type, 4-fluorine-substituted benzenium, 1,2,3,5,6-pentamethylbenzenium and 1-naphthalenium ions a similar dependence has been established... 

The NMR- F spectroscopy has been used to investigate the polyfluorinated I-naphthalenium ions 12. 0.238,239,413,414) Examples are the chemical shifts of the... 

However, other explanations of the reactions observed are not precluded. Thus, for polyfluorinated arenium ions a preliminary conversion of the ions into radical cations of the respective aromatic structures is discussed. Indeed, the radical cation of octafluoronaphthalene reacts with pentafluorobenzene to yield the same products as the perfluoro-a-naphthalenium ion does. 

The benzbicyclo[3.1.0]hexenyl cation converts into the 1-H-naphthalenium ion at -50 °C in HSO3F-SO2CIF... 

NMR spectra have been recorded for l-X-l,2-dimethyl-3,4,5,6-tetrafluoro- and -tetrachlorobenzenium ions (X=H Cl ) l-(X-phenyl)-l,3,4,5,6-pentamethyl-2-hydroxy- and l-(X-phenyl)-l,2,3,5,6-pentamethyl-4-hydroxyl nzenium ions isomeric tri- and tetramethvl-l-H-naphthalenium ions 2- and 4-p-chloroethyl-1-H-naphthalenium ions oc-naphtonium ions of the (167) type 2- and 3-sub-... 

Other examples of cerium(III)-assisted reductions include reactions of derivatives of biologically active principals from Podocarpus plants (Hayashi and Matsumoto, 1982), and the preparation of precursors of stable carbocations derived from a-ethylene naphthalenium ions (Olah and Singh, 1982) ... 

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