1021319-07-2Relevant academic research and scientific papers
Revealing phenylium, phenonium, yinylenephenonium, and benzenium ions in solution
Manet, Ilse,Monti, Sandra,Grabner, Gottfried,Protti, Stefano,Dondi, Daniele,Dichiarante, Valentina,Fagnoni, Maurizio,Albini, Angelo
, p. 1029 - 1039 (2008)
The 4-methoxyphenylium ion has been generated in the triplet state ( 3An+) by photolysis of 4-chloroanisole in polar media and detected by flash photolysis (λmax = 400nm). This is the first detection of a phenylium ion in solution by flash photolysis and the assignment is supported by time-dependent density functional theory (TD-DFT) calculations. In neat solvents, the cation was reduced to anisole, a process initiated by electron transfer from the starting compound (3An+ + AnCl→An?+AnCf?+, with the radical cation detected at 470 nm, then An?→ AnH). Addition of π nucleophiles to the 3An+ cation offers a novel access to a number of other cationic intermediates under mild, nonacidic conditions. Two intermediates are successively formed with alkenes, a diradical cation and the phenonium ion, which are detected at 440 and 320 nm, respectively, by flash photolysis and are in accordance with calculations. Allylanisoles or β-alkoxyalkylanisoles are the end products, with a small amount of α-alkoxyalkylanisoles that arises from a Wagner-Meerwein rearrangement to form benzyl cations. Further intermediates that have been predicted and detected are the phenylvinylium ion, possibly in equilibrium with the vinylenephenonium ion, with 1-hexyne (λmax = 340 nm) and the benzenium ion with benzene (λmax = 380nm). The final products were anisylhexyne and methoxybiphenyl (an analogous product and intermediate were detected with thiophene).
