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.
G. Bencivenni, R. Cesari, D. Nanni, H. El Mkami, J. C. Walton (2010). EPR and ENDOR Spectroscopic Study of the Reactions of Aromatic Azides with Gallium Trichloride. ORGANIC & BIOMOLECULAR CHEMISTRY, 8, 5097-5104 [10.1039/c0ob00084a].
EPR and ENDOR Spectroscopic Study of the Reactions of Aromatic Azides with Gallium Trichloride
BENCIVENNI, GIORGIO;NANNI, DANIELE;
2010
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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
