EPR and pulsed ENDOR study of intermediates from reactions of aromatic azides with group 13 metal trichlorides
نویسندگان
چکیده
The reactions of group 13 metal trichlorides with aromatic azides were examined by CW EPR and pulsed ENDOR spectroscopies. Complex EPR spectra were obtained from reactions of aluminium, gallium and indium trichlorides with phenyl azides containing a variety of substituents. Analysis of the spectra showed that 4-methoxy-, 3-methoxy- and 2-methoxyphenyl azides all gave 'dimer' radical cations [ArNHC₆H₄NH₂](+•) and trimers [ArNHC₆H₄NHC₆H₄NH₂](+•) followed by polymers. 4-Azidobenzonitrile, with its electron-withdrawing substituent, did not react. In general the aromatic azides appeared to react most rapidly with AlCl₃ but this reagent tended to generate much polymer. InCl₃ was the least reactive group 13 halide. DFT computations of the radical cations provided corroborating evidence and suggested that the unpaired electrons were accommodated in extensive π-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.
منابع مشابه
EPR and ENDOR spectroscopic study of the reactions of aromatic azides with gallium trichloride.
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 d...
متن کاملDirect spectroscopic detection of framework-incorporated vanadium in mesoporous silica materials.
Framework-incorporated vanadium mesoporous silica materials with different contents in vanadium were obtained by a facile, direct synthesis at room temperature, using VOSO4 x 5H2O as the vanadium precursor. The porous characteristics of the samples and the coordination environment of the vanadia in the structure were studied by a combination of techniques: X-ray diffraction, N2-adsorption/desor...
متن کاملPorphyrin Cobalt(III) "Nitrene Radical" Reactivity; Hydrogen Atom Transfer from Ortho-YH Substituents to the Nitrene Moiety of Cobalt-Bound Aryl Nitrene Intermediates (Y = O, NH).
In the field of cobalt(II) porphyrin-catalyzed metallo-radical reactions, organic azides have emerged as successful nitrene transfer reagents. In the pursuit of employing ortho-YH substituted (Y = O, NH) aryl azides in Co(II) porphyrin-catalyzed nitrene transfer reactions, unexpected hydrogen atom transfer (HAT) from the OH or NH₂ group in the ortho-position to the nitrene moiety of the key rad...
متن کاملHydrazines and azides via the metal-catalyzed hydrohydrazination and hydroazidation of olefins.
The discovery, study, and implementation of the Co- and Mn-catalyzed hydrohydrazination and hydroazidation reactions of olefins are reported. These reactions are equivalent to direct hydroaminations of C-C double bonds with protected hydrazines or hydrazoic acid but are based on a different concept in which the H and the N atoms come from two different reagents, a silane and an oxidizing nitrog...
متن کاملStructure, EPR/ENDOR and DFT characterisation of a [Cu(II)(en)2](OTf)2 complex.
The Jahn-Teller distorted Cu(II) complex [Cu(en)2](OTf)2 1 (en = 1,2-diaminoethane) has been reported and characterised using X-ray crystallography, EPR and ENDOR spectroscopy, and DFT calculations. The solid state structure shows an intra- and inter-molecular hydrogen-bonded network via the N-H groups and the coordinated triflate anions. CW and pulsed EPR/ENDOR were used to determine the spin ...
متن کامل