Protection against Peroxynitrite-Mediated Nitration Reaction by Intramolecularly Coordinated Diorganoselenides

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• 作者：Sangit Kumar ; Harkesh B. Singh ; and Gotthelf Wolmershä ; user
• 刊名：Organometallics
• 出版年：2006
• 出版时间：January 16, 2006
• 年：2006
• 卷：25
• 期：2
• 页码：382 - 393
• 全文大小：249K
• 年卷期：v.25,no.2(January 16, 2006)
• ISSN：1520-6041

文摘

A series of intramolecularly Se···X (X = N, O) coordinated diorganoselenides and -sulfides aresynthesized by using the heteroatom-directed lithiation route and characterized by multinuclear (¹H, ¹³C,⁷⁷Se) NMR, IR spectroscopy, and electrospray mass spectrometry (ES-MS). The intramolecular Se···Ointeractions in diorganoselenides 26-31 have been studied by multinuclear NMR studies in solution andin the solid state by single-crystal X-ray crystallography. The protection against peroxynitrite-mediatednitration reaction (PN assay) by diorganoselenides/-sulfides (with and without intramolecular coordination)has been evaluated. The PN assay data of diorganoselenides reveal that the selenides 20-22, having abasic amino group (sp³-N donor) in close proximity of selenium, are more active compared to thediorganoselenides 16-19, having an imino group (sp²-N donor), and also show much higher protectiveaction than the unsubstituted diorganoselenides 14 and 15. The diorganoselenides 16-31 were oxidizedto corresponding selenoxides 44-59. The redox properties of the selenoxides 13 and 44-59 have beeninvestigated by cyclic voltammetry and potentiometric titration experiments. Two redox potentials for insitu-generated ferrocenyl selenoxides (50, 54-59) were observed. The reduction of selenoxides 13 and48 to ebselen (2) and selenide 20 with benzenethiol (PhSH) was monitored by ES-MS.