{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,7]],"date-time":"2026-10-07T03:16:27Z","timestamp":1791342987578,"version":"4.3.1"},"reference-count":0,"publisher":"National Academy of Sciences","issue":"8","content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[1975,8]]},"abstract":"\n Irradiation of Ru(bipy)\n 3<\/jats:sub>\n 2+<\/jats:sup>\n (bipy = 2,2\u2032-bipyridine) with light below 560 nm results in the formation of a charge-transfer excited state potentially capable of reducing water to dihydrogen with concomitant production of Ru(bipy)\n 3<\/jats:sub>\n 3+<\/jats:sup>\n . The latter may be reduced by hydroxide [Formula: see text] to form dioxygen and regenerate the starting complex. The use of these reactions in a cell designed to bring about the photochemical decomposition of water is proposed.\n <\/jats:p>\n \n The stoichiometry, kinetics, and mechanism of the Ru(bipy)\n 3<\/jats:sub>\n 3+<\/jats:sup>\n -hydroxide reaction have been investigated by conventional and stopped-flow spectrophotometry. The dioxygen yield is a sharp function of pH, attaining its maximum value (about 80%) at pH 9. At low pH (3 and 4.8) the production of ruthenium(II) is first order with\n k<\/jats:italic>\n obsd<\/jats:sub>\n = (1.41 \u00b1 0.04) \u00d7 10\n -4<\/jats:sup>\n sec\n -1<\/jats:sup>\n (25\u00b0, ionic strength \u03bc = 1.00 M with sodium sulfate). In the intermediate pH range (7.9-10.0) complex kinetics are observed. In the hydroxide range 0.01-0.50 M, ruthenium(II) production is predominantly first order with\n k<\/jats:italic>\n obsd<\/jats:sub>\n =\n k<\/jats:italic>\n a<\/jats:sub>\n [OH\n -<\/jats:sup>\n ] +\n k<\/jats:italic>\n b<\/jats:sub>\n [OH\n -<\/jats:sup>\n ]\n 2<\/jats:sup>\n sec\n -1<\/jats:sup>\n ;\n k<\/jats:italic>\n a<\/jats:sub>\n = 148 M\n -1<\/jats:sup>\n sec\n -1<\/jats:sup>\n and\n k<\/jats:italic>\n b<\/jats:sub>\n = 138 M\n -2<\/jats:sup>\n sec\n -1<\/jats:sup>\n (25\u00b0, \u03bc = 1.00 M, sodium sulfate). For the\n k<\/jats:italic>\n a<\/jats:sub>\n term, the activation parameters are \u0394H\n \u2021<\/jats:sup>\n = 15.3 \u00b1 1.0 kcal mol\n -1<\/jats:sup>\n and \u0394S\n \u2021<\/jats:sup>\n = 7 \u00b1 3 cal deg\n -1<\/jats:sup>\n mol\n -1<\/jats:sup>\n (1 cal = 4.184 J). An intermediate species (\u03bb\n max<\/jats:sub>\n 800 nm) forms at the same rate as ruthenium(II) in this hydroxide range. It disappears with\n k<\/jats:italic>\n obsd<\/jats:sub>\n = 1.2 + 1.1 \u00d7 10\n 2<\/jats:sup>\n [OH\n -<\/jats:sup>\n ] sec\n -1<\/jats:sup>\n at 25\u00b0. Similarly absorbing (\u03bb\n max<\/jats:sub>\n 750 to 800 nm) species are generated by the addition of hydroxyl radical to M(bipy)\n 3<\/jats:sub>\n 2+\/3+<\/jats:sup>\n [M = Fe(II), Os(II), Ru(II), Cr(III), Ru(III)] in pulse radiolysis experiments. The kinetics above pH 7 are described in terms of rate-determining nucleophilic attack by hydroxide on the bound bipyridine ring. The hydroxide adduct so generated is tentatively identified with that observed in the pulse radiolysis experiments with Ru(bipy)\n 3<\/jats:sub>\n 2+<\/jats:sup>\n .\n <\/jats:p>\n \n For reduction of Ru(bipy)\n 3<\/jats:sub>\n 3+<\/jats:sup>\n by hydrogen peroxide ruthenium(II) production is first order with\n k<\/jats:italic>\n obsd<\/jats:sub>\n =\n k<\/jats:italic>\n c<\/jats:sub>\n [HO\n 2<\/jats:sub>\n -<\/jats:sup>\n ] +\n k<\/jats:italic>\n d<\/jats:sub>\n [H\n 2<\/jats:sub>\n O\n 2<\/jats:sub>\n ] where\n k<\/jats:italic>\n c<\/jats:sub>\n = 5.4 \u00d7 10\n 7<\/jats:sup>\n M\n -1<\/jats:sup>\n sec\n -1<\/jats:sup>\n and\n k<\/jats:italic>\n d<\/jats:sub>\n = 8.3 M\n -1<\/jats:sup>\n sec\n -1<\/jats:sup>\n (25\u00b0, \u03bc = 1.00 M, pH 3.5 to 9.7). This reaction produces dioxygen in 83 \u00b1 15% yield at pH 6.8 and in 1.0 N sulfuric acid.\n <\/jats:p>","DOI":"10.1073\/pnas.72.8.2858","type":"journal-article","created":{"date-parts":[[2006,5,31]],"date-time":"2006-05-31T03:09:44Z","timestamp":1149044984000},"page":"2858-2862","update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":280,"title":["Reaction of tris(bipyridine)ruthenium(III) with hydroxide and its application in a solar energy storage system"],"prefix":"10.1073","volume":"72","author":[{"given":"Carol","family":"Creutz","sequence":"first","affiliation":[{"name":"Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Norman","family":"Sutin","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[1975,8]]},"container-title":["Proceedings of the National Academy of Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.72.8.2858","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,4,13]],"date-time":"2022-04-13T11:01:09Z","timestamp":1649847669000},"score":1,"resource":{"primary":{"URL":"https:\/\/pnas.org\/doi\/full\/10.1073\/pnas.72.8.2858"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1975,8]]},"references-count":0,"journal-issue":{"issue":"8","published-print":{"date-parts":[[1975,8]]}},"alternative-id":["10.1073\/pnas.72.8.2858"],"URL":"https:\/\/doi.org\/10.1073\/pnas.72.8.2858","relation":{},"ISSN":["0027-8424","1091-6490"],"issn-type":[{"value":"0027-8424","type":"print"},{"value":"1091-6490","type":"electronic"}],"subject":[],"published":{"date-parts":[[1975,8]]},"assertion":[{"value":"1975-08-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}