Single electron transfer azides

The reduction of alkylazides by single electron transfer (SET) cleanly furnishes the alkyl-aminyl radicals plus molecular nitrogen. A variety of metal reagents and photochemical methods exist. The reaction can also be performed with organic radicals, which add to the azide and release dinitrogen, too (see also Section 8.3.2). The resulting aminyl radical can be simply reduced to the corresponding amine or can further react with radical traps (olefins) to form C-N bonds. 

The mechanism studies showed that single electron transfer (SET) process is involved in the transformation (Scheme 4.16). The oxidation of NaN3 gives azide radical which subsequently traps benzylic radical to give benzylic azide... 

In addition to the electronic features associated with the Fe-O-Fe group, some metHrX complexes also exhibit X-to-Fe(III) charge-transfer transitions (98, 99, 105). For example, the azide complex shows a broad band near 445 nm, which in single-crystal absorbance data is polarized perpendicular to the Fe-Fe axis and becomes resolved into two features at 485 and 442 nm at 77 K (98). Upon laser excitation into the visible band, vibrations associated with an Fe-Nj stretch and intra-azide stretches are observed (106, 107). 

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