Kinetics and mechanism of reaction of trans-(diaqua)(N,N′-ethylene-bis-salicylidenimine) chromium(iii) with sulfur(iv): The labilizing effect of coordinated sulfite

✍ Scribed by Anadi C. Dash; Achyuta N. Acharya; Prakash Mohanty; Arabinda Das

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 226 KB
• Volume: 30
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/(sici)1097-4601(1998)30:5<373::aid-kin8>3.0.co;2-p

✦ Synopsis

The reaction of trans-[Cr(Salen)(OH 2 ) 2 ] ϩ with aqueous sulfite yields trans-[Cr(Salen)(OH 2 )(OSO 2 9 O)] Ϫ (O-bonded isomer). The rate and activation parameter data for the formation of the sulfito complex are consistent with a mechanism involving rate-limiting addition of SO 2 to the bond. The complex ions, trans-[(OH 2 )Cr(Salen)(OSO 2 9O)] Ϫ , III Cr 9OH and trans-undergo reversible anation by NCS Ϫ , imidazole, 2Ϫ Ϫ [(OH)Cr(Salen)(OSO 9O)] , N , 2 3 and pyridine resulting in the formation of trans-( for (nϩ1)Ϫ [XCr(Salen)(OSO 9O)] n ϭ 1 Xϭ 2 NCS Ϫ , and 0 for and pyridine) predominantly via dissociative interchange Ϫ N , X ϭ imidazole 3 mechanism. The labilizing action of the coordinated sulfite on the trans-bond in III Cr -X follows the sequence: ca. ca. imidazole. (nϩ1)Ϫ Ϫ Ϫ trans-[XCr(Salen)(OSO )] NCS Ͻ pyridine N 2 3

Data analysis indicated that the coordinated sulfite has little trans activating influence.