New insight into photochemistry of ferrioxalate.
Optical spectroscopy and nanosecond flash photolysis (Nd:YAG laser, 355 nm, pulse duration 5 ns, mean energy 5 mJ/pulse) were used to study the photochemistry of Fe(III)(C2O4)3(3-) complex in aqueous solutions. The main photochemical process was found to be intramolecular electron transfer from the ligand to Fe(III) ion with formation of a primary radical complex [(C2O4)2Fe(II)(C2O4(*))](3-). The yield of radical species (i.e., CO2(*-) and C2O4(*-)) was found to be less than 6% of Fe(III)(C2O4)3(3-) disappeared after flash. [(C2O4)2Fe(II)(C2O4(*))](3-) dissociates reversibly into oxalate ion and a secondary radical complex, [(C2O4)Fe(II)(C2O4(*))](-). The latter reacts with the initial complex and dissociates to Fe(II)(C2O4) and oxalate radical. In this framework, the absorption spectra and rate constants of the reactions of all intermediates were determined.
Pozdnyakov
Ivan P
IP
Institute of Chemical Kinetics and Combustion, Institutskaya 3, and Novosibirsk State University, Pirogova 2, 630090 Novosibirsk, Russia. pozdnyak@kinetics.nsc.ru
Kel
Oksana V
OV
Plyusnin
Victor F
VF
Grivin
Vjacheslav P
VP
Bazhin
Nikolai M
NM
D000042:Absorption; D004579:Electron Transport; D005609:Free Radicals / Q000737:chemistry; D007834:Lasers; D008024:Ligands; D010070:Oxalates / Q000737:chemistry*; D010777:Photochemistry; D010782:Photolysis; D012996:Solutions / Q000737:chemistry; D013053:Spectrophotometry; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
D005609:Free Radicals; D008024:Ligands; D010070:Oxalates; D012996:Solutions; D014867:Water; C034942:ferrioxalate