Aromaten, Elektrophile Substitution?

Hey, Ich habe zwei Fragen zu der Elektrophilen Substitution von Chlor und Benzol.

  1. wieso ist das Carbenium-Ion des Sigma-Komplexes ein reelles Teilchen und nicht nur ein Übergangszustand?
  2. Wie kann man das Carbenium-Ion nachweisen?
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ADFischer
1 year ago

Compounds containing carbenium ions can be crystallized with suitable anions and the structure can be determined. The ions can therefore be detected directly.

ZitrusLiebe
1 year ago

I think you’re referring to electrophilic aromatic substitution?

Many exotic compounds such as carbenium ions and carbonium ions can be obtained as salt. Usually only under protective gas or at low temperatures, but anyway.

In most cases, weakly interacting anions such as BF4, PF6, AsF6 or SbCl6 are taken. The KAtion additionally carries bulky groups such as trityl, mesityl, (perfluoro-)phenyl.

Tritylium, cyclopropylium and tropylium salts, Whealand complexes, Meisenheimer complexes are examples. Only X-ray structure analysis must be carried out. That’s the gold standard.

Further detection possibilities: NMR, possibly (ESI) mass spectra, electron diffraction, IR/Raman.

ZitrusLiebe
1 year ago
Reply to  Xerox314

As I said, it is possible to intercept the intermediary areniumion of the SeAr if that was not clear. This is not possible with TSOs as with the Sn2 of my knowledge. These are classics in kinetics. Alternatively, there is the arine mechanism, the SnAr and others.

Here you always argue with energy diagrams. The TSO has no dent, the Intermediat has a small one.