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A selenenic acid is an organoselenium compound and an oxoacid with the general formula RSeOH, where R ≠ H. It is the first member of the family of organoselenium oxoacids, which also include seleninic acids and selenonic acids, which are RSeO2H and RSeO3H, respectively. Selenenic acids derived from selenoenzymes are thought to be responsible for the antioxidant activity of these enzymes. ==Properties== In contrast to selenonic and seleninic acids, selenenic acids are unstable with respect to a self-condensation reaction to form the corresponding selenoseleninates〔A. Ishii, S. Matsubayashi, T. Takahashi, J. Nakayama, "Preparation of a selenenic acid and isolation of selenoseleninates" ''J. Org. Chem.'' 1999, 64, 1084–1085. 〕 or disproportionation into corresponding seleninic acids and diselenides: :2 RSeOH → RSe(O)SeR + H2O :2 RSeOH → RSeO2H + 1/2 RSeSeR Even the very bulky 2,4,6-tri-''tert''-butylbenzeneselenenic acid disproportionates readily.〔H. J. Reich, C. P. Jasperse, "Organoselenium chemistry. Preparation and reactions of 2,4,6-tri-''tert''-butylbenzeneselenenic acid" ''J. Org. Chem.'' 1988, 53, 2389–2390. 〕 A stable selenenic acid was synthesized by burying the SeOH functional group within the cavity of a ''p''-''tert''-butyl. X-ray crystallographic analysis revealed the Se-O bond length to be 1.763 Å. The S-O absorbs in the IR spectrum at 680–700 cm−1.〔T. Saiki, K. Goto, R. Okazaki, “Isolation and X-ray crystallographic analysis of a stable selenenic acid” ''Angew. Chem. Int. Ed.'' 1997, 36, 2223–2224. 〕 In a stable selenenic acid prepared by oxidizing a highly hindered selenol, BmtSeH, the Se-O bond length was found to be 1.808 Å while the O-Se-C angle was 96.90°. Oxidation of BmtSeOH gave BmtSeO2H.〔K. Goto, M. Nagahama, T. Mizushima, K. Shimada, T. Kawahima, R. Okazaki, “The first direct oxidative conversion of a selenol to a stable selenenic acid: Experimental demonstration of three processes included in the catalytic cycle of glutathione peroxidase” ''Org. Lett.'' 2001, 3, 3569–3572. 〕 Selenenic acids are believed to be transient intermediates in a number of redox reactions involving organoselenium compounds. One notable example is the ''syn''-elimination of selenoxides. Selenenic acids are also transient intermediates in the reduction of seleninic acids as well as the oxidatlon of diselenides. The reasoning for postulating selenenic acids as reactive intermediates is based in part on analogy with their more extensively studied sulfenic acid analogs.〔D. L. Klayman, W. H. H. Gunther ''Organic Selenium Compounds: Their Chemistry and Biology'', Wiley, 1973. ISBN 0-471-49032-6〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「selenenic acid」の詳細全文を読む スポンサード リンク
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