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U.S.A."],"published-print":{"date-parts":[[2005,5,24]]},"abstract":"\n The acidity constants for (N3)H of the uridine-type ligands (U) 5-fluorouridine, 5-chloro-2\u2032-deoxyuridine, uridine, and thymidine (2\u2032-deoxy-5-methyluridine) and the stability constants of the M(U\u2013H)\n +<\/jats:sup>\n complexes for M\n 2+<\/jats:sup>\n = Mg\n 2+<\/jats:sup>\n , Ca\n 2+<\/jats:sup>\n , Sr\n 2+<\/jats:sup>\n , Ba\n 2+<\/jats:sup>\n , Mn\n 2+<\/jats:sup>\n , Co\n 2+<\/jats:sup>\n , Ni\n 2+<\/jats:sup>\n , Cu\n 2+<\/jats:sup>\n , Zn\n 2+<\/jats:sup>\n , Cd\n 2+<\/jats:sup>\n , and Pb\n 2+<\/jats:sup>\n were measured (potentiometric pH titrations; aqueous solution; 25\u00b0C;\n I<\/jats:italic>\n = 0.1 M, NaNO\n 3<\/jats:sub>\n ). Plots of\n \n \\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{log}}K_{{\\mathrm{M}}({\\mathrm{U}}-{\\mathrm{H}})}^{{\\mathrm{M}}}\\end{equation*}\\end{document}<\/jats:tex-math>\n <\/jats:inline-formula>\n vs.\n \n \\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{p}}K_{{\\mathrm{U}}}^{{\\mathrm{H}}}\\end{equation*}\\end{document}<\/jats:tex-math>\n <\/jats:inline-formula>\n result in straight lines that are compared with previous plots for simple pyridine-type and\n o<\/jats:italic>\n -amino(methyl)pyridine-type ligands as well as with the stabilities of the corresponding M(cytidine)\n 2+<\/jats:sup>\n complexes. The results indicate monodentate coordination to (N3)\n \u2013<\/jats:sup>\n in M(U\u2013H)\n +<\/jats:sup>\n for Co\n 2+<\/jats:sup>\n and Ni\n 2+<\/jats:sup>\n . For the M(U\u2013H)\n +<\/jats:sup>\n species of Cd\n 2+<\/jats:sup>\n , Zn\n 2+<\/jats:sup>\n , or Cu\n 2+<\/jats:sup>\n , increased stabilities imply that semichelates form, i.e., M\n 2+<\/jats:sup>\n is (N3)\n \u2013<\/jats:sup>\n -bound and coordinated water molecules form hydrogen bonds to (C2)O and (C4)O; these \u201cdouble\u201d semichelates are in equilibrium with \u201csingle\u201d semichelates involving either (C2)O or (C4)O and possibly also with four-membered chelates for which M\n 2+<\/jats:sup>\n is innersphere-coordinated to (N3)\n \u2013<\/jats:sup>\n and a carbonyl oxygen. For the alkaline earth ions, semichelates dominate with the M\n 2+<\/jats:sup>\n outersphere bound to (N3)\n \u2013<\/jats:sup>\n and innersphere to one of the carbonyl oxygens. Mn(U\u2013H)\n +<\/jats:sup>\n is with its properties between those of Cd\n 2+<\/jats:sup>\n (which probably also hold for Pb\n 2+<\/jats:sup>\n ) and the alkaline earth ions. In nucleic acids, M\n 2+<\/jats:sup>\n \u2013C(O) interactions are expected, if support is provided by other primary binding sites. (N3)H may possibly be acidified via carbonyl-coordinated M\n 2+<\/jats:sup>\n to become a proton donor in the physiological pH range, at which direct (N3)\n \u2013<\/jats:sup>\n binding of M\n 2+<\/jats:sup>\n also seems possible.\n <\/jats:p>","DOI":"10.1073\/pnas.0501446102","type":"journal-article","created":{"date-parts":[[2005,5,16]],"date-time":"2005-05-16T20:35:10Z","timestamp":1116275710000},"page":"7459-7464","update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":64,"title":["Metal ion-binding properties of (N3)-deprotonated uridine, thymidine, and related pyrimidine nucleosides in aqueous solution"],"prefix":"10.1073","volume":"102","author":[{"given":"Bernd","family":"Knobloch","sequence":"first","affiliation":[{"name":"Department of Chemistry, Inorganic Chemistry, University of Basel, Spitalstrasse 51, CH-4056 Basel, Switzerland; and Institute of Applied Synthetic Chemistry, Technical University of Vienna, Getreidemarkt 9, A-1060 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wolfgang","family":"Linert","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Inorganic Chemistry, University of Basel, Spitalstrasse 51, CH-4056 Basel, Switzerland; and Institute of Applied Synthetic Chemistry, Technical University of Vienna, Getreidemarkt 9, A-1060 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Helmut","family":"Sigel","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Inorganic Chemistry, University of Basel, Spitalstrasse 51, CH-4056 Basel, Switzerland; and Institute of Applied Synthetic Chemistry, Technical University of Vienna, Getreidemarkt 9, A-1060 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[2005,5,16]]},"reference":[{"key":"e_1_3_2_1_2","first-page":"1","volume":"42","year":"2004","unstructured":"Sigel, A. & Sigel, H., eds. 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