{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T13:29:08Z","timestamp":1790861348245,"version":"4.1.0"},"reference-count":36,"publisher":"National Academy of Sciences","issue":"11","content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[2002,5,28]]},"abstract":"<jats:p>\n                    The thermodynamic properties of aqueous nitroxyl (HNO) and its anion (NO\n                    <jats:sup>\u2212<\/jats:sup>\n                    ) have been revised to show that the ground state of NO\n                    <jats:sup>\u2212<\/jats:sup>\n                    is triplet and that HNO in its singlet ground state has much lower acidity, pKa(\n                    <jats:sup>1<\/jats:sup>\n                    HNO\/\n                    <jats:sup>3<\/jats:sup>\n                    NO\n                    <jats:sup>\u2212<\/jats:sup>\n                    ) \u2248 11.4, than previously believed. These conclusions are in accord with the observed large differences between\n                    <jats:sup>1<\/jats:sup>\n                    HNO and\n                    <jats:sup>3<\/jats:sup>\n                    NO\n                    <jats:sup>\u2212<\/jats:sup>\n                    in their reactivities toward O\n                    <jats:sub>2<\/jats:sub>\n                    and NO. Laser flash photolysis was used to generate\n                    <jats:sup>1<\/jats:sup>\n                    HNO and\n                    <jats:sup>3<\/jats:sup>\n                    NO\n                    <jats:sup>\u2212<\/jats:sup>\n                    by photochemical cleavage of trioxodinitrate (Angeli's anion). The spin-allowed addition of\n                    <jats:sup>3<\/jats:sup>\n                    O\n                    <jats:sub>2<\/jats:sub>\n                    to\n                    <jats:sup>3<\/jats:sup>\n                    NO\n                    <jats:sup>\u2212<\/jats:sup>\n                    produced peroxynitrite with nearly diffusion-controlled rate (\n                    <jats:italic>k<\/jats:italic>\n                    = 2.7 \u00d7 10\n                    <jats:sup>9<\/jats:sup>\n                    M\n                    <jats:sup>\u22121<\/jats:sup>\n                    \u22c5s\n                    <jats:sup>\u22121<\/jats:sup>\n                    ). In contrast, the spin-forbidden addition of\n                    <jats:sup>3<\/jats:sup>\n                    O\n                    <jats:sub>2<\/jats:sub>\n                    to\n                    <jats:sup>1<\/jats:sup>\n                    HNO was not detected (\n                    <jats:italic>k<\/jats:italic>\n                    \u226a 3 \u00d7 10\n                    <jats:sup>5<\/jats:sup>\n                    M\n                    <jats:sup>\u22121<\/jats:sup>\n                    \u22c5s\n                    <jats:sup>\u22121<\/jats:sup>\n                    ). Both\n                    <jats:sup>1<\/jats:sup>\n                    HNO and\n                    <jats:sup>3<\/jats:sup>\n                    NO\n                    <jats:sup>\u2212<\/jats:sup>\n                    reacted sequentially with two NO to generate N\n                    <jats:sub>3<\/jats:sub>\n                    O\n                    <jats:inline-formula>\n                      <jats:tex-math notation=\"LaTeX\">\\documentclass[12pt]{minimal}\n\\usepackage{amsmath}\n\\usepackage{wasysym} \n\\usepackage{amsfonts} \n\\usepackage{amssymb} \n\\usepackage{amsbsy}\n\\usepackage{mathrsfs}\n\\setlength{\\oddsidemargin}{-69pt}\n\\begin{document}\n\\begin{equation*}{\\mathrm{_{3}^{-}}}\\end{equation*}\\end{document}<\/jats:tex-math>\n                    <\/jats:inline-formula>\n                    as a long-lived intermediate; the rate laws of N\n                    <jats:sub>3<\/jats:sub>\n                    O\n                    <jats:inline-formula>\n                      <jats:tex-math notation=\"LaTeX\">\\documentclass[12pt]{minimal}\n\\usepackage{amsmath}\n\\usepackage{wasysym} \n\\usepackage{amsfonts} \n\\usepackage{amssymb} \n\\usepackage{amsbsy}\n\\usepackage{mathrsfs}\n\\setlength{\\oddsidemargin}{-69pt}\n\\begin{document}\n\\begin{equation*}{\\mathrm{_{3}^{-}}}\\end{equation*}\\end{document}<\/jats:tex-math>\n                    <\/jats:inline-formula>\n                    formation were linear in concentrations of NO and\n                    <jats:sup>1<\/jats:sup>\n                    HNO (\n                    <jats:italic>k<\/jats:italic>\n                    = 5.8 \u00d7 10\n                    <jats:sup>6<\/jats:sup>\n                    M\n                    <jats:sup>\u22121<\/jats:sup>\n                    \u22c5s\n                    <jats:sup>\u22121<\/jats:sup>\n                    ) or NO and\n                    <jats:sup>3<\/jats:sup>\n                    NO\n                    <jats:sup>\u2212<\/jats:sup>\n                    (\n                    <jats:italic>k<\/jats:italic>\n                    = 2.3 \u00d7 10\n                    <jats:sup>9<\/jats:sup>\n                    M\n                    <jats:sup>\u22121<\/jats:sup>\n                    \u22c5s\n                    <jats:sup>\u22121<\/jats:sup>\n                    ). Catalysis by the hydroxide ion was observed for the reactions of\n                    <jats:sup>1<\/jats:sup>\n                    HNO with both O\n                    <jats:sub>2<\/jats:sub>\n                    and NO. This effect is explicable by a spin-forbidden deprotonation by OH\n                    <jats:sup>\u2212<\/jats:sup>\n                    (\n                    <jats:italic>k<\/jats:italic>\n                    = 4.9 \u00d7 10\n                    <jats:sup>4<\/jats:sup>\n                    M\n                    <jats:sup>\u22121<\/jats:sup>\n                    \u22c5s\n                    <jats:sup>\u22121<\/jats:sup>\n                    ) of the relatively unreactive\n                    <jats:sup>1<\/jats:sup>\n                    HNO into the extremely reactive\n                    <jats:sup>3<\/jats:sup>\n                    NO\n                    <jats:sup>\u2212<\/jats:sup>\n                    . Dimerization of\n                    <jats:sup>1<\/jats:sup>\n                    HNO to produce N\n                    <jats:sub>2<\/jats:sub>\n                    O occurred much more slowly (\n                    <jats:italic>k<\/jats:italic>\n                    = 8 \u00d7 10\n                    <jats:sup>6<\/jats:sup>\n                    M\n                    <jats:sup>\u22121<\/jats:sup>\n                    \u22c5s\n                    <jats:sup>\u22121<\/jats:sup>\n                    ) than previously suggested. The implications of these results for evaluating the biological roles of nitroxyl are discussed.\n                  <\/jats:p>","DOI":"10.1073\/pnas.112202099","type":"journal-article","created":{"date-parts":[[2002,7,26]],"date-time":"2002-07-26T10:46:49Z","timestamp":1027680409000},"page":"7340-7345","update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":412,"title":["Nitroxyl and its anion in aqueous solutions: Spin states, protic equilibria, and reactivities toward oxygen and nitric oxide"],"prefix":"10.1073","volume":"99","author":[{"given":"Vladimir","family":"Shafirovich","sequence":"first","affiliation":[{"name":"Chemistry Department and Radiation and Solid-State Laboratory, New York University, New York, NY 10003; and Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sergei V.","family":"Lymar","sequence":"additional","affiliation":[{"name":"Chemistry Department and Radiation and Solid-State Laboratory, New York University, New York, NY 10003; and Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[2002,5,21]]},"reference":[{"key":"e_1_3_2_1_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.88.23.10860"},{"key":"e_1_3_2_2_2","doi-asserted-by":"publisher","DOI":"10.1006\/bbrc.1993.2307"},{"key":"e_1_3_2_3_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.91.23.10992"},{"key":"e_1_3_2_4_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.93.25.14492"},{"key":"e_1_3_2_5_2","doi-asserted-by":"publisher","DOI":"10.1042\/bj3320009"},{"key":"e_1_3_2_6_2","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.M104237200"},{"key":"e_1_3_2_7_2","doi-asserted-by":"publisher","DOI":"10.1080\/02603598808072309"},{"key":"e_1_3_2_8_2","first-page":"3","volume-title":"Methods in Nitric Oxide Research","author":"Bonner F T","year":"1996","unstructured":"F T Bonner, G Stedman Methods in Nitric Oxide Research, eds M Feelisch, J S Stamler (Wiley, Chichester), pp. 3\u201318 (1996)."},{"key":"e_1_3_2_9_2","doi-asserted-by":"publisher","DOI":"10.1063\/1.444702"},{"key":"e_1_3_2_10_2","doi-asserted-by":"publisher","DOI":"10.1088\/0022-3700\/8\/7\/021"},{"key":"e_1_3_2_11_2","doi-asserted-by":"publisher","DOI":"10.1021\/ic50007a063"},{"key":"e_1_3_2_12_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0005-2728(99)00019-5"},{"key":"e_1_3_2_13_2","doi-asserted-by":"publisher","DOI":"10.1021\/ic00236a004"},{"key":"e_1_3_2_14_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja00384a070"},{"key":"e_1_3_2_15_2","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.M006174200"},{"key":"e_1_3_2_16_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0891-5849(01)00477-4"},{"key":"e_1_3_2_17_2","doi-asserted-by":"publisher","DOI":"10.1002\/bbpc.19700740322"},{"key":"e_1_3_2_18_2","doi-asserted-by":"publisher","DOI":"10.1139\/v73-166"},{"key":"e_1_3_2_19_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0898-8838(08)60194-4"},{"key":"e_1_3_2_20_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0022-0728(68)80144-5"},{"key":"e_1_3_2_21_2","first-page":"154","volume":"25","author":"Benderskii V A","year":"1989","unstructured":"V A Benderskii, A G Krivenko, E A Ponomarev Sov Electrochem 25, 154\u2013161 (1989).","journal-title":"Sov Electrochem"},{"key":"e_1_3_2_22_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.041481598"},{"key":"e_1_3_2_23_2","doi-asserted-by":"crossref","unstructured":"Addison C. 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