Flash Photolysis Studies of Roussin's Black Salt Anion: Fe(4)S(3)(NO)(7)(-).
A time-resolved optical (UV-vis) spectroscopic study of Roussin's black salt anion, Fe(4)S(3)(NO)(7)(-), revealed two separate intermediates, X and Y, following laser flash photolysis. Both intermediates react with nitric oxide with second-order kinetics to re-form the parent complex (k(NO)(X)() = 1.3 x 10(7) M(-)(1) s(-)(1); k(NO)(Y)() = 7.0 x 10(5) M(-)(1) s(-)(1) in aqueous solutions). The shorter-lived intermediate X was observed in time resolved infrared spectroscopic studies. Isotopic labeling experiments involving the exchange of black salt nitrosyls with (15)NO(2)(-) or (15)N(18)O were used to probe the correlation between nu(NO) bands and the anion structures. The identities of the intermediates are interpreted in terms of photolytic loss of chemically distinct nitrosyls found on the Fe(4)S(3)(NO)(7)(-) anion.
Bourassa
James
J
Department of Chemistry, University of California, Santa Barbara Santa Barbara, California 93106-9510, and Integrated Spectroscopy Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545.
Lee
Brian
B
Bernard
Stefan
S
Schoonover
Jon
J
Ford
Peter C.
PC