Generation of nitric oxide by photolysis of silver hyponitrite in suspension induced by LMCT excitation

Photo release of nitrous oxide from the hyponitrite ion studied by infrared spectroscopy. Evidence for the generation of a cobalt-N2O complex. Experimental and DFT calculations

“…The electronic spectrum of a silver hyponitrite suspension reported by Kumkely et al [8], shows absorption bands at 207(sh), 255(sh) and 419 nm (wide). The last band was assigned to LMCT (Ligand Metal Charge Transfer).…”

“…However, this transition fails to reproduce the photolysis and the spectral shifts observed in thallium and silver hyponitrites. We then hypothesize that this is a possible (reversible) charge transfer transition proposed in the reference [8] from hyponitrite to metal that was not taken into account in the theoretical approach. On the other hand, the energy difference between HOMO hyponitrite and LUMO configurations for the Na + , Tl + and Ag + ions in aqueous solution is expected in the sequence ΔE Na N ΔE Tl N ΔE Ag in agreement with the experimental electronic spectral shifts.…”

“…To check if silver remains in the oxidation state I after Ag 2 N 2 O 2 photolysis, the chemical reaction proposed in [8] was tested. It was noted that the black solid contacted with ammonia solution (50%) dissolved immediately at room temperature.…”

“…The hyponitrite ion and its conjugate acids are in equilibrium in aqueous solution; depending on the pH, all these species undergo decomposition [7]. In the photolysis of an aqueous suspension of silver hyponitrite, NO was generated as a consequence of light irradiation [8].…”

“…Nitrous oxide (N 2 O) may be considered a derivative of the hyponitrite ion because the hyponitrous acid (HONNOH) decomposes in aqueous solutions (pH [4][5][6][7][8][9][10][11][12][13][14] into N 2 O [7]. Nitrous oxide has been used in anesthetic practices for more than 150 years, and considered a major advance in anesthetics.…”