{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,4]],"date-time":"2026-10-04T18:43:51Z","timestamp":1791139431571,"version":"4.1.0"},"reference-count":101,"publisher":"Wiley","issue":"4","license":[{"start":{"date-parts":[[2006,11,22]],"date-time":"2006-11-22T00:00:00Z","timestamp":1164153600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Chemistry A European J"],"published-print":{"date-parts":[[2007,1,22]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>\n                    The tautomerism of cyameluric acid C\n                    <jats:sub>6<\/jats:sub>\n                    N\n                    <jats:sub>7<\/jats:sub>\n                    O\n                    <jats:sub>3<\/jats:sub>\n                    H\n                    <jats:sub>3<\/jats:sub>\n                    (\n                    <jats:bold>1\u2009a<\/jats:bold>\n                    ), cyamelurates and other heptazine derivatives has recently been studied by several theoretical investigations. In this experimental study we prepared stannyl and silyl derivatives of cyameluric acid (\n                    <jats:bold>1\u2009a<\/jats:bold>\n                    ): C\n                    <jats:sub>6<\/jats:sub>\n                    N\n                    <jats:sub>7<\/jats:sub>\n                    O\n                    <jats:sub>3<\/jats:sub>\n                    [Sn(C\n                    <jats:sub>4<\/jats:sub>\n                    H\n                    <jats:sub>9<\/jats:sub>\n                    )\n                    <jats:sub>3<\/jats:sub>\n                    ]\n                    <jats:sub>3<\/jats:sub>\n                    (\n                    <jats:bold>3\u2009a<\/jats:bold>\n                    ), C\n                    <jats:sub>6<\/jats:sub>\n                    N\n                    <jats:sub>7<\/jats:sub>\n                    O\n                    <jats:sub>3<\/jats:sub>\n                    [Sn(C\n                    <jats:sub>2<\/jats:sub>\n                    H\n                    <jats:sub>5<\/jats:sub>\n                    )\n                    <jats:sub>3<\/jats:sub>\n                    ]\n                    <jats:sub>3<\/jats:sub>\n                    (\n                    <jats:bold>3\u2009b<\/jats:bold>\n                    ), and C\n                    <jats:sub>6<\/jats:sub>\n                    N\n                    <jats:sub>7<\/jats:sub>\n                    O\n                    <jats:sub>3<\/jats:sub>\n                    [Si(CH\n                    <jats:sub>3<\/jats:sub>\n                    )\n                    <jats:sub>3<\/jats:sub>\n                    ]\n                    <jats:sub>3<\/jats:sub>\n                    (\n                    <jats:bold>4<\/jats:bold>\n                    ). In order to investigate the structure of\n                    <jats:bold>1\u2009a<\/jats:bold>\n                    the mono\u2010 and dipotassium cyamelurate hydrates K(C\n                    <jats:sub>6<\/jats:sub>\n                    N\n                    <jats:sub>7<\/jats:sub>\n                    O\n                    <jats:sub>3<\/jats:sub>\n                    H\n                    <jats:sub>2<\/jats:sub>\n                    )\n                    <jats:bold>\u22c5<\/jats:bold>\n                    2\u2009H\n                    <jats:sub>2<\/jats:sub>\n                    O (\n                    <jats:bold>5<\/jats:bold>\n                    ) and K\n                    <jats:sub>2<\/jats:sub>\n                    (C\n                    <jats:sub>6<\/jats:sub>\n                    N\n                    <jats:sub>7<\/jats:sub>\n                    O\n                    <jats:sub>3<\/jats:sub>\n                    H)\n                    <jats:bold>\u22c5<\/jats:bold>\n                    1\u2009H\n                    <jats:sub>2<\/jats:sub>\n                    O (\n                    <jats:bold>6<\/jats:bold>\n                    ) were synthesized by UV\/Vis\u2010controlled titration of a potassium cyamelurate solution with aqueous hydrochloric acid. Compounds\n                    <jats:bold>3\u20136<\/jats:bold>\n                    were characterized by FTIR and solid\u2010state NMR spectroscopy as well as simultaneous thermal analysis (TGA, DTA). The single crystal X\u2010ray structures of the salts\n                    <jats:bold>5<\/jats:bold>\n                    and\n                    <jats:bold>6<\/jats:bold>\n                    show that the hydrogen atoms in both anions are localized on the peripheral nitrogen atoms. This indicates\u2014in combination with the solid\u2010state NMR studies\u2014that the most stable tautomer of solid\n                    <jats:bold>1\u2009a<\/jats:bold>\n                    is the triketo form with\n                    <jats:italic>C<\/jats:italic>\n                    <jats:sub>\n                      3\n                      <jats:italic>h<\/jats:italic>\n                    <\/jats:sub>\n                    symmetry. However, derivatives of both the hydroxyl and the amido tautomers may be formed depending on the substituent atoms: The spectroscopic data and single crystal structures of compounds C\n                    <jats:sub>6<\/jats:sub>\n                    N\n                    <jats:sub>7<\/jats:sub>\n                    O\n                    <jats:sub>3<\/jats:sub>\n                    [Si(CH\n                    <jats:sub>3<\/jats:sub>\n                    )\n                    <jats:sub>3<\/jats:sub>\n                    ]\n                    <jats:sub>3<\/jats:sub>\n                    (\n                    <jats:bold>4<\/jats:bold>\n                    ) and the solvate C\n                    <jats:sub>6<\/jats:sub>\n                    N\n                    <jats:sub>7<\/jats:sub>\n                    O\n                    <jats:sub>3<\/jats:sub>\n                    [Sn(C\n                    <jats:sub>2<\/jats:sub>\n                    H\n                    <jats:sub>5<\/jats:sub>\n                    )\n                    <jats:sub>3<\/jats:sub>\n                    ]\n                    <jats:sub>3<\/jats:sub>\n                    <jats:bold>\u22c5<\/jats:bold>\n                    C\n                    <jats:sub>2<\/jats:sub>\n                    H\n                    <jats:sub>4<\/jats:sub>\n                    Cl\n                    <jats:sub>2<\/jats:sub>\n                    (\n                    <jats:bold>3\u2009b<\/jats:bold>\n                    \u2032) show that the former is derived from the symmetric trihydroxy form of\n                    <jats:bold>1\u2009a<\/jats:bold>\n                    , while\n                    <jats:bold>3\u2009b<\/jats:bold>\n                    \u2032 crystallizes as a chain\u2010like polymer, which contains the tin atoms as multifunctional building blocks, that is, bridging pentacoordinated Et\n                    <jats:sub>3<\/jats:sub>\n                    SnO\n                    <jats:sub>2<\/jats:sub>\n                    and Et\n                    <jats:sub>3<\/jats:sub>\n                    SnON units as well as non\u2010bridging four\u2010coordinated Et\n                    <jats:sub>3<\/jats:sub>\n                    SnN units. The cyameluric nucleus is part of the polymeric chains of C\n                    <jats:sub>6<\/jats:sub>\n                    N\n                    <jats:sub>7<\/jats:sub>\n                    O\n                    <jats:sub>3<\/jats:sub>\n                    [Sn(C\n                    <jats:sub>2<\/jats:sub>\n                    H\n                    <jats:sub>5<\/jats:sub>\n                    )\n                    <jats:sub>3<\/jats:sub>\n                    ]\n                    <jats:sub>3<\/jats:sub>\n                    <jats:bold>\u22c5<\/jats:bold>\n                    C\n                    <jats:sub>2<\/jats:sub>\n                    H\n                    <jats:sub>4<\/jats:sub>\n                    Cl\n                    <jats:sub>2<\/jats:sub>\n                    (\n                    <jats:bold>3\u2009b<\/jats:bold>\n                    \u2032), by the action of both tautomeric forms of cyameluric acid, the amide and the ester form.\n                  <\/jats:p>","DOI":"10.1002\/chem.200600435","type":"journal-article","created":{"date-parts":[[2006,11,22]],"date-time":"2006-11-22T06:19:11Z","timestamp":1164176351000},"page":"1158-1173","source":"Crossref","is-referenced-by-count":81,"title":["The Tautomeric Forms of Cyameluric Acid Derivatives"],"prefix":"10.1002","volume":"13","author":[{"given":"Nadia\u2005E.\u2005A.","family":"El\u2010Gamel","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lena","family":"Seyfarth","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J\u00f6rg","family":"Wagler","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Helmut","family":"Ehrenberg","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marcus","family":"Schwarz","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J\u00fcrgen","family":"Senker","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Edwin","family":"Kroke","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2007,1,9]]},"reference":[{"key":"e_1_2_6_1_2","unstructured":"Further synonyms:sym\u2010heptazine 1 3 4 6 7 9 9b\u2010heptaaza\u2010phenallene 1 3 4 6 7 9\u2010heexaazacyclo[3.3.3]azine or cyamelurine."},{"key":"e_1_2_6_2_2","doi-asserted-by":"publisher","DOI":"10.1016\/0040-4020(96)00840-X"},{"key":"e_1_2_6_3_2","doi-asserted-by":"publisher","DOI":"10.2174\/1385272043369845"},{"key":"e_1_2_6_4_2","doi-asserted-by":"publisher","DOI":"10.1039\/b111062b"},{"key":"e_1_2_6_5_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ccr.2004.02.001"},{"key":"e_1_2_6_6_2","unstructured":"\u00a0"},{"key":"e_1_2_6_7_2","doi-asserted-by":"publisher","DOI":"10.1103\/PhysRevB.32.7988"},{"key":"e_1_2_6_8_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.245.4920.841"},{"key":"e_1_2_6_9_2","doi-asserted-by":"publisher","DOI":"10.1103\/PhysRevB.41.10727"},{"key":"e_1_2_6_10_2","unstructured":"\u00a0"},{"key":"e_1_2_6_11_2","first-page":"10","volume":"10","author":"Liebig J.","year":"1834","journal-title":"Ann. Chem."},{"key":"e_1_2_6_12_2","doi-asserted-by":"publisher","DOI":"10.1002\/jlac.18500730217"},{"key":"e_1_2_6_13_2","first-page":"257","volume":"10","author":"Liebig J.","year":"1850","journal-title":"Ann. Chem."},{"key":"e_1_2_6_14_2","unstructured":"E. Kroke Habilitation"},{"key":"e_1_2_6_15_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.23.12.615"},{"key":"e_1_2_6_16_2","unstructured":"\u00a0"},{"key":"e_1_2_6_17_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja01267a056"},{"key":"e_1_2_6_18_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja01861a038"},{"key":"e_1_2_6_19_2","unstructured":"\u00a0"},{"key":"e_1_2_6_20_2","first-page":"1132","volume":"31","author":"Finkel'shtein A. I.","year":"1961","journal-title":"Zh. Obshch. Khim."},{"key":"e_1_2_6_21_2","first-page":"606","volume":"1","author":"Finkel'shtein A. I.","year":"1964","journal-title":"Zh. Org. Khim."},{"key":"e_1_2_6_22_2","doi-asserted-by":"publisher","DOI":"10.1070\/RC1964v033n07ABEH001443"},{"key":"e_1_2_6_23_2","first-page":"972","volume":"7","author":"Koryakin A. G.","year":"1971","journal-title":"Zh. Org. Khim."},{"key":"e_1_2_6_24_2","first-page":"153","volume":"19","author":"Zhagrova N. I.","year":"1973","journal-title":"Zh. Prikl. Spektrosk."},{"key":"e_1_2_6_25_2","first-page":"452","volume":"48","author":"Zhagrova N. I.","year":"1975","journal-title":"Zh. Prikl. Khim."},{"key":"e_1_2_6_26_2","unstructured":"\u00a0"},{"key":"e_1_2_6_27_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja00384a046"},{"key":"e_1_2_6_28_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja00322a014"},{"key":"e_1_2_6_29_2","doi-asserted-by":"publisher","DOI":"10.1021\/j150663a026"},{"key":"e_1_2_6_30_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja00299a021"},{"key":"e_1_2_6_31_2","doi-asserted-by":"publisher","DOI":"10.1002\/1521-3757(20020517)114:10<1871::AID-ANGE1871>3.0.CO;2-S"},{"key":"e_1_2_6_31_3","first-page":"1792","volume":"41","year":"2002","journal-title":"Angew. Chem. Int. Ed."},{"key":"e_1_2_6_32_2","doi-asserted-by":"publisher","DOI":"10.1021\/ic051583m"},{"key":"e_1_2_6_33_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo00016a011"},{"key":"e_1_2_6_34_2","unstructured":"See for example:"},{"key":"e_1_2_6_35_2","doi-asserted-by":"publisher","DOI":"10.1021\/jp048713h"},{"key":"e_1_2_6_36_2","doi-asserted-by":"publisher","DOI":"10.1021\/cm010929y"},{"key":"e_1_2_6_37_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jnoncrysol.2004.02.080"},{"key":"e_1_2_6_38_2","unstructured":"See for example:"},{"key":"e_1_2_6_39_2","first-page":"57","author":"Souto S.","year":"1998","journal-title":"Phys. Rev. B"},{"key":"e_1_2_6_40_2","first-page":"60","author":"Vaziri M.","year":"2006","journal-title":"Mater. Lett."},{"key":"e_1_2_6_41_2","first-page":"5","author":"Ewels C. P.","year":"2005","journal-title":"J. Nanosci. Nanotechnol."},{"key":"e_1_2_6_42_2","unstructured":"\u00a0"},{"key":"e_1_2_6_43_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja0357689"},{"key":"e_1_2_6_44_2","doi-asserted-by":"publisher","DOI":"10.1002\/zaac.200500363"},{"key":"e_1_2_6_45_2","doi-asserted-by":"publisher","DOI":"10.1002\/zaac.200500017"},{"key":"e_1_2_6_46_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja048939y"},{"key":"e_1_2_6_47_2","doi-asserted-by":"publisher","DOI":"10.1039\/B412517G"},{"key":"e_1_2_6_48_2","doi-asserted-by":"publisher","DOI":"10.1039\/b416390g"},{"key":"e_1_2_6_49_2","doi-asserted-by":"publisher","DOI":"10.1002\/zaac.200500252"},{"key":"e_1_2_6_50_2","doi-asserted-by":"publisher","DOI":"10.1002\/ejoc.200400308"},{"key":"e_1_2_6_51_2","first-page":"98","author":"Williams G. K.","year":"1994","journal-title":"Combust. Flame"},{"key":"e_1_2_6_52_2","unstructured":"Heptazine derivatives are mentioned in almost any patent application related to flame retardants for recent examples see:"},{"key":"e_1_2_6_53_2","unstructured":"C.Perego F.\u2005P.\u2005M.Mercx R.Puyenbroek R.Kumaraswamy H.Manjunath S.Charati(General Electric Company USA) PCT Int. Appl. WO 2005118698\u2009A1 2005;"},{"key":"e_1_2_6_54_2","unstructured":"G.\u2005I.Titelman S.Bron (Bromine Compounds Ltd. Israel) PCT Int. Appl. WO 2005101976\u2009A2 2005;"},{"key":"e_1_2_6_55_2","unstructured":"X.Couillens M.Amorese(Rhodia Engineering Plastics S.R.L. Italy) PCT Int. Appl. WO 2005061606\u2005A1 2005;"},{"key":"e_1_2_6_56_2","unstructured":"H.Ohyama H.Matsui N.Maeda(Mitsubishi Engineering\u2010Plastics Corporation Japan) Eur. Pat. Appl. EP 1533343\u2009A1 2005."},{"key":"e_1_2_6_57_2","doi-asserted-by":"publisher","DOI":"10.1039\/b310375g"},{"key":"e_1_2_6_58_2","unstructured":"\u00a0"},{"key":"e_1_2_6_59_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0021-9673(98)00441-5"},{"key":"e_1_2_6_60_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0021-9673(96)00495-5"},{"key":"e_1_2_6_61_2","unstructured":"\u00a0"},{"key":"e_1_2_6_62_2","first-page":"545","volume":"68","author":"Gavrilova T. B.","year":"1994","journal-title":"Zh. Fiz. Khim."},{"key":"e_1_2_6_63_2","first-page":"1080","volume":"66","author":"Gavrilova T. B.","year":"1992","journal-title":"Zh. Fiz. Khim."},{"key":"e_1_2_6_64_2","unstructured":"\u00a0"},{"key":"e_1_2_6_65_2","doi-asserted-by":"publisher","DOI":"10.1021\/jp035558i"},{"key":"e_1_2_6_66_2","doi-asserted-by":"publisher","DOI":"10.1021\/jp037078x"},{"key":"e_1_2_6_67_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.theochem.2003.11.020"},{"key":"e_1_2_6_68_2","doi-asserted-by":"publisher","DOI":"10.1021\/jp046909b"},{"key":"e_1_2_6_69_2","doi-asserted-by":"publisher","DOI":"10.1021\/jp045827k"},{"key":"e_1_2_6_70_2","doi-asserted-by":"publisher","DOI":"10.3998\/ark.5550190.0005.415"},{"key":"e_1_2_6_71_2","doi-asserted-by":"publisher","DOI":"10.1021\/jp0520650"},{"key":"e_1_2_6_72_2","doi-asserted-by":"publisher","DOI":"10.1002\/jcc.20165"},{"key":"e_1_2_6_73_2","unstructured":"E.\u2005M. Smolin L. Rapoport"},{"key":"e_1_2_6_74_2","doi-asserted-by":"publisher","DOI":"10.1002\/ejic.200500672"},{"key":"e_1_2_6_75_2","unstructured":"\u00a0"},{"key":"e_1_2_6_76_2","doi-asserted-by":"publisher","DOI":"10.1002\/cber.18860190297"},{"key":"e_1_2_6_77_2","doi-asserted-by":"publisher","DOI":"10.1039\/p29820001321"},{"key":"e_1_2_6_78_2","doi-asserted-by":"publisher","DOI":"10.1080\/00397919308011217"},{"key":"e_1_2_6_79_2","unstructured":"\u00a0"},{"key":"e_1_2_6_80_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0038-1098(98)00631-0"},{"key":"e_1_2_6_81_2","doi-asserted-by":"publisher","DOI":"10.1039\/a908903i"},{"key":"e_1_2_6_82_2","first-page":"31","author":"Wilson E. K.","journal-title":"Chem. Eng. News"},{"key":"e_1_2_6_83_2","doi-asserted-by":"publisher","DOI":"10.1246\/nikkashi1948.85.3_159"},{"key":"e_1_2_6_84_2","first-page":"284","author":"Huyge\u2010Tiprez G.","year":"1977","journal-title":"Comptes Rendus des Seances de l\u2032Academie des Sciences, Serie C: Sciences Chimiques"},{"key":"e_1_2_6_85_2","first-page":"1653","volume":"46","author":"Dergunov Y. I.","year":"1976","journal-title":"Zh. Obshch. Khim."},{"key":"e_1_2_6_86_2","first-page":"1129","volume":"2","author":"Gordetsov A. S.","year":"1989","journal-title":"Metalloorg. Khim."},{"key":"e_1_2_6_87_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ssnmr.2003.10.002"},{"key":"e_1_2_6_88_2","doi-asserted-by":"publisher","DOI":"10.1021\/jp0256443"},{"key":"e_1_2_6_89_2","doi-asserted-by":"publisher","DOI":"10.1021\/jp0040751"},{"key":"e_1_2_6_90_2","doi-asserted-by":"publisher","DOI":"10.1002\/zaac.200500478"},{"key":"e_1_2_6_91_2","first-page":"162","volume":"245","author":"Seifer G. B.","year":"1979","journal-title":"Dokl. Akad. Nauk SSSR"},{"key":"e_1_2_6_92_2","first-page":"69","author":"Wagler J.","year":"2006","journal-title":"Z. Naturforsch. B"},{"key":"e_1_2_6_93_2","doi-asserted-by":"publisher","DOI":"10.1002\/zaac.200600099"},{"key":"e_1_2_6_94_2","unstructured":"MATLAB The Language of Technical Computing MathWorks Inc. Copyricht 1984\u20131998 24 Prime Park Way Natick MA 01760\u20101500."},{"key":"e_1_2_6_95_2","doi-asserted-by":"publisher","DOI":"10.1016\/0009-2614(90)87239-N"},{"key":"e_1_2_6_96_2","unstructured":"\u00a0"},{"key":"e_1_2_6_97_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0009-2614(01)00578-4"},{"key":"e_1_2_6_98_2","first-page":"219","author":"Metz G.","journal-title":"J. Magn. Reson. A110"},{"key":"e_1_2_6_99_2","doi-asserted-by":"publisher","DOI":"10.1063\/1.470372"},{"key":"e_1_2_6_100_2","doi-asserted-by":"publisher","DOI":"10.1006\/jmra.1993.1092"}],"container-title":["Chemistry \u2013 A European Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1002%2Fchem.200600435","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/chemistry-europe.onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/chem.200600435","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T10:51:44Z","timestamp":1760266304000},"score":1,"resource":{"primary":{"URL":"https:\/\/chemistry-europe.onlinelibrary.wiley.com\/doi\/10.1002\/chem.200600435"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2007,1,9]]},"references-count":101,"journal-issue":{"issue":"4","published-print":{"date-parts":[[2007,1,22]]}},"alternative-id":["10.1002\/chem.200600435"],"URL":"https:\/\/doi.org\/10.1002\/chem.200600435","archive":["Portico"],"relation":{},"ISSN":["0947-6539","1521-3765"],"issn-type":[{"value":"0947-6539","type":"print"},{"value":"1521-3765","type":"electronic"}],"subject":[],"published":{"date-parts":[[2007,1,9]]}}}