Photolysis of a High-Spin Azidoiron(III) Complex Studied by Time-Resolved Fourier-Transform Infrared Spectroscopy.

The laser-flash photolysis of the high-spin azidoiron(III) complex [FeIII (Me3 Cyclam-ac)(N3 )]PF6 ([1]PF6 ) in liquid acetonitrile solution at room temperature was explored by time-resolved Fourier-transform infrared spectroscopy. Excitation of [1] at 480 and 266 nm induced a photoreduction of the metal center and generated [FeII (Me3 Cyclam-ac)(NCCH3 )]+ ([2]) and azidyl radicals. Both photoproducts were detected independently through scavenging experiments. The metal-containing fragment was quenched with carbon monoxide to generate an iron(II) carbonyl complex, whereas the nitrogen-containing fragment was quenched with iodide to form azide anions. In the presence of N3- , the photoreduction created the elusive hexanitrogen radical anion N6.- as a transient byproduct.