The reactions of gallium trichloride with phenyl and deuterio-phenyl azides, as well as with 4-methoxyphenyl azide and deuterium isotopomers, were examined by product analysis, CW EPR spectroscopy and pulsed ENDOR spectroscopy. The products included the corresponding anilines together with 4-aminodiphenylamine type dimers, and polyanilines. Complex CW EPR spectra of the radical cations of the dimers [ArNHC6H4NH2]+∑ and trimers [ArNHC6H4NHC6H4NH2]+∑ were obtained. These EPR spectra were analysed with the help of data from the deuterium-substituted analogues as well as the pulse Davies ENDOR spectra. DFT computations of the radical cations provided corroborating evidence and suggested the unpaired electrons were accommodated in extensive p-delocalised orbitals. A mechanism to account for the reductive conversion of aromatic azides to the corresponding anilines and thence to the dimers and trimers is proposed.
Titolo: | EPR and ENDOR Spectroscopic Study of the Reactions of Aromatic Azides with Gallium Trichloride |
Autore/i: | BENCIVENNI, GIORGIO; R. Cesari; NANNI, DANIELE; H. El Mkami; J. C. Walton |
Autore/i Unibo: | |
Anno: | 2010 |
Rivista: | |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1039/c0ob00084a |
Abstract: | The reactions of gallium trichloride with phenyl and deuterio-phenyl azides, as well as with 4-methoxyphenyl azide and deuterium isotopomers, were examined by product analysis, CW EPR spectroscopy and pulsed ENDOR spectroscopy. The products included the corresponding anilines together with 4-aminodiphenylamine type dimers, and polyanilines. Complex CW EPR spectra of the radical cations of the dimers [ArNHC6H4NH2]+∑ and trimers [ArNHC6H4NHC6H4NH2]+∑ were obtained. These EPR spectra were analysed with the help of data from the deuterium-substituted analogues as well as the pulse Davies ENDOR spectra. DFT computations of the radical cations provided corroborating evidence and suggested the unpaired electrons were accommodated in extensive p-delocalised orbitals. A mechanism to account for the reductive conversion of aromatic azides to the corresponding anilines and thence to the dimers and trimers is proposed. |
Data prodotto definitivo in UGOV: | 2010-12-21 15:03:45 |
Appare nelle tipologie: | 1.01 Articolo in rivista |