Kinetic studies on the periodate oxidation of an iron(II) oxime-imine complex

✍ Scribed by Basudeb Saha; Sumana Gangopadhyay; Pradyot Banerjee; Mahammad Ali

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 134 KB
• Volume: 31
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/(sici)1097-4601(1999)31:1<23::aid-kin3>3.0.co;2-7

✦ Synopsis

The iron(II) complex of H 2 L 14-dimethyl-4, 7, 10, 13-tetraazahexadeca-(H L ϭ 3, 2 3,13-diene-2,15-dione dioxime, Coord. Chem. Rev., 33, 87 (1980)) is oxidized by periodate very rapidly in the range pH 2.0-7.0, and the kinetics of the reaction has been followed by stoppedflow spectrophotometry at 30ЊC and ionic strength (NaClO 4 ). The reaction is Ϫ1 I ϭ 0.20 mol L found to follow a simple second-order kinetics as

II 2ϩ

Ϫd/dt[Fe (H L) ] ϭ k 2 giving [Fe III (L)] ϩ and IO 3 Ϫ as the final products. The reaction has been proposed to occur through a H-bonded transition state formed probably between the protonated oxime group of the ligand and the oxygen atom on the periodate species, followed by an electron transfer from Fe II centre to I VII in a rate-determining step. The I VI species thus generated reacts in a fast step with another Fe II complex.