{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T19:31:56Z","timestamp":1790364716944,"version":"4.1.0"},"reference-count":128,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[2010,11,24]],"date-time":"2010-11-24T00:00:00Z","timestamp":1290556800000},"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":[[2011,1,3]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>\n                    Triazolophanes are used as the venue to compete an aliphatic propylene CH hydrogen\u2010bond donor against an aromatic phenylene one. Longer aliphatic C\uf8ffH\n                    <jats:bold>\u22c5\u22c5\u22c5<\/jats:bold>\n                    Cl\n                    <jats:sup>\u2212<\/jats:sup>\n                    hydrogen bonds were calculated from the location of the chloride within the propylene\u2010based triazolophane. The gas\u2010phase energetics of chloride binding (\u0394\n                    <jats:italic>G<\/jats:italic>\n                    <jats:sub>bind<\/jats:sub>\n                    , \u0394\n                    <jats:italic>H<\/jats:italic>\n                    <jats:sub>bind<\/jats:sub>\n                    , \u0394\n                    <jats:italic>S<\/jats:italic>\n                    <jats:sub>bind<\/jats:sub>\n                    ) and the configurational entropy (\u0394\n                    <jats:italic>S<\/jats:italic>\n                    <jats:sub>config<\/jats:sub>\n                    ) were computed by taking all low\u2010energy conformations into account. Comparison between the phenylene\u2010 and propylene\u2010based triazolophanes shows the computed gas\u2010phase free energy of binding decreased from \u0394\n                    <jats:italic>G<\/jats:italic>\n                    <jats:sub>bind<\/jats:sub>\n                    =\u2212194 to \u2212182\u2005kJ\u2009mol\n                    <jats:sup>\u22121<\/jats:sup>\n                    , respectively, with a modest enthalpy\u2013entropy compensation. These differences were investigated experimentally. An\n                    <jats:sup>1<\/jats:sup>\n                    H\u2005NMR spectroscopy study on the structure of the propylene triazolophane\u2019s 1:1 chloride complex is consistent with a weaker propylene CH hydrogen bond. To quantify the affinity differences between the two triazolophanes in dichloromethane, it was critical to obtain an accurate binding model. Four equilibria were identified. In addition to 1:1 complexation and 2:1 sandwich formation, ion pairing of the tetrabutylammonium chloride salt (TBA\n                    <jats:sup>+<\/jats:sup>\n                    <jats:bold>\u22c5<\/jats:bold>\n                    Cl\n                    <jats:sup>\u2212<\/jats:sup>\n                    ) and cation pairing of TBA\n                    <jats:sup>+<\/jats:sup>\n                    with the 1:1 triazolophane\u2013chloride complex were observed and quantified. Each complex was independently verified by ESI\u2010MS or diffusion NMR spectroscopy. With ion pairing deconvoluted from the chloride\u2013receptor binding, equilibrium constants were determined by using\n                    <jats:sup>1<\/jats:sup>\n                    H\u2005NMR (500\u2005\u03bc\n                    <jats:sc>M<\/jats:sc>\n                    ) and UV\/Vis (50\u2005\u03bc\n                    <jats:sc>M<\/jats:sc>\n                    ) spectroscopy titrations. The stabilities of the 1:1 complexes for the phenylene and propylene triazolophanes did not differ within experimental error, \u0394\n                    <jats:italic>G<\/jats:italic>\n                    =(\u221238\u00b12) and (\u221239\u00b11)\u2005kJ\u2009mol\n                    <jats:sup>\u22121<\/jats:sup>\n                    , respectively, as verified by an NMR spectroscopy competition experiment. Thus, the aliphatic CH donor only revealed its weaker character when competing with aromatic CH donors within the propylene\u2010based triazolophane.\n                  <\/jats:p>","DOI":"10.1002\/chem.201002340","type":"journal-article","created":{"date-parts":[[2010,11,24]],"date-time":"2010-11-24T10:42:44Z","timestamp":1290595364000},"page":"312-321","source":"Crossref","is-referenced-by-count":107,"title":["Aromatic and Aliphatic CH Hydrogen Bonds Fight for Chloride while Competing Alongside Ion Pairing within Triazolophanes"],"prefix":"10.1002","volume":"17","author":[{"given":"Yuran","family":"Hua","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Raghunath O.","family":"Ramabhadran","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Esther O.","family":"Uduehi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jonathan A.","family":"Karty","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Krishnan","family":"Raghavachari","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Amar H.","family":"Flood","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2010,11,24]]},"reference":[{"key":"e_1_2_6_1_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja01002a035"},{"key":"e_1_2_6_2_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja01011a047"},{"key":"e_1_2_6_3_2","unstructured":"\u00a0"},{"key":"e_1_2_6_4_2","volume-title":"Supramolecular Chemistry of Anions","author":"Bianchi A.","year":"1997"},{"key":"e_1_2_6_5_2","doi-asserted-by":"publisher","DOI":"10.1039\/9781847552471"},{"key":"e_1_2_6_6_2","unstructured":"Top. 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Consequently the 0.2\u2005ppm shift represents only 29.5\u2009% of the methylene protons engaged in the hydrogen bonding. Therefore this 0.2\u2005ppm can be scaled by 1\/29.5\u2009%=0.7\u2005ppm."},{"key":"e_1_2_6_108_2","unstructured":"The magnitude of complexation\u2010induced signal migrations (\u0394\u03b4\/ppm) for both triazole protons and internal phenylene protons qualitatively correlate to the calculated average H\u22c5\u22c5\u22c5Cl\u2212distances (d\/\u00c5). Order of contact distance: Ha<Hb<Hc<Hd<Hh; order of signal migration: Ha>Hb>Hc>Hd>Hh. However it is worthwhile to point out that the magnitude of signal migrations might not be solely dependent on the contact distance."},{"key":"e_1_2_6_109_2","unstructured":"This position was established from studies on the tetraphenylborate (TPB\u2212) salt of TBA+(see the Supporting Information)."},{"key":"e_1_2_6_110_2","doi-asserted-by":"publisher","DOI":"10.1039\/a802954g"},{"key":"e_1_2_6_111_2","unstructured":"Such types of shielding is also evidenced from the crystal structure of a similar salt see Cambridge Structure Database refcode: ERAPIW."},{"key":"e_1_2_6_112_2","unstructured":"The NMR spectroscopy titration for1with TBA+\u22c5Cl\u2212is less insightful on account of significant signal broadening."},{"key":"e_1_2_6_113_2","unstructured":"An additional signal for triazolophane1was observed corresponding to the iodide sandwich12\u22c5I\u2212 but not with triazolophane2under the same conditions. The iodide sandwich was believed to result from scavenging in the ESI\u2010MS experiment as seen previously. A competition experiment using ESI\u2010MS (see the Supporting Information) in which 25\u2005\u03bcMof1and2are analyzed in the presence of TBA+\u22c5Cl\u2212 showed the12\u22c5I\u2212complex but not22\u22c5I\u2212. Formation of iodide sandwich with triazolophanes has been seen before see reference\u2005[8c]."},{"key":"e_1_2_6_114_2","unstructured":"Evidence for22\u22c5Cl\u2212\u22c5TBA+from diffusion NMR spectroscopy is weak. On the basis of Fuoss\u2019 law [21]the ion pairing is expected to be too weak in a titration experiment at 1\u2005mM. When titration experiments are conducted at even lower concentrations the population of22\u22c5Cl\u2212\u22c5TBA+will be smaller still. Therefore the quantitative NMR (500\u2005\u03bcM) and UV (50\u2005\u03bcM) spectroscopy titrations have been modeled with the four primary equilibria [Eq.\u2005(1)\u2013(4)]. Consistently global fitting of the NMR spectroscopy data (see the Supporting Information) shows that addition of the fifth equilibrium for the formation of22\u22c5Cl\u2212\u22c5TBA+had no effect on the outcome of the fitting."},{"key":"e_1_2_6_115_2","unstructured":"The NMR spectroscopy titration data for triazolophane1(Figure\u20057\u2009a)[8a]was not applicable for HypNMR fitting on account of significant signal broadening."},{"key":"e_1_2_6_116_2","doi-asserted-by":"publisher","DOI":"10.1021\/ic700553d"},{"key":"e_1_2_6_117_2","volume-title":"Analytical Methods in Supramolecular Chemistry","author":"Hirose K.","year":"2007"}],"container-title":["Chemistry \u2013 A European Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1002%2Fchem.201002340","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/chemistry-europe.onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/chem.201002340","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T12:37:36Z","timestamp":1760272656000},"score":1,"resource":{"primary":{"URL":"https:\/\/chemistry-europe.onlinelibrary.wiley.com\/doi\/10.1002\/chem.201002340"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2010,11,24]]},"references-count":128,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2011,1,3]]}},"alternative-id":["10.1002\/chem.201002340"],"URL":"https:\/\/doi.org\/10.1002\/chem.201002340","archive":["Portico"],"relation":{},"ISSN":["0947-6539","1521-3765"],"issn-type":[{"value":"0947-6539","type":"print"},{"value":"1521-3765","type":"electronic"}],"subject":[],"published":{"date-parts":[[2010,11,24]]}}}