Catalyzed Autoxidation of Hydrogensulfite by Cobalt(II) (2,3,9,10-tetramethyl-1,4,8,11-tetraaza-cyclotetradeca-1,3,8,10-tetraene) (H 2 O) 2 2+ |
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| Authors: | Ela Solomon-Rapaport Alexandra Masarwa Haim Cohen Dan Meyerstein |
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| Affiliation: | 1. Department of Chemistry , Ben-Gurion University of the Negev , Beer-Sheva , Israel;2. Department of Chemistry , Ben-Gurion University of the Negev , Beer-Sheva , Israel;3. Nuclear Research Centre Negev , Beer-Sheva , Israel;4. The College of Judea and Samaria , Ariel , Israel |
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| Abstract: | ![]()
The catalytic autoxidation of hydrogensulfite (hydrogentrioxosulfate(1-)) in the presence of Co(tim)(H 2 O) 2 2+ (tim=2,3,9,10-tetramethyl-1,4,8,11-tetraazacyclotetradeca-1,3,8,10-tetraene) was studied. Dioxygen reacts with excess sulfite in the presence of Co(tim)(H 2 O) 2 2+ in a complex process (a minimum of five kinetic steps can be identified) to produce Co(tim)(SO 3 ) x (3 m 2 x )+ ( x =1 or 2) ( u max at 350 nm) and sulfate. Seventy turnovers over 4 h were attained in a system where dioxygen and sulfite were supplied constantly. The Co(III) product formed reacts only slowly with dioxygen to produce sulfate. A mechanistic analysis of the results implies the involvement of a Co(tim)-dioxygen adduct, stabilized by an axial sulfite ligand. |
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| Keywords: | Cobalt Complexes Catalyzed Autoxidation Sulfite (hydrogentrioxosulfate(1-)) Dioxygen |
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