{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,14]],"date-time":"2026-10-14T12:39:40Z","timestamp":1791981580163,"version":"4.4.0"},"reference-count":26,"publisher":"National Academy of Sciences","issue":"26","content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[2009,6,30]]},"abstract":"\n The self-assembled heterocapsule 1\u00b72, which is formed by the hydrogen bonds of tetra(4-pyridyl)-cavitand 1 and tetrakis(4-hydroxyphenyl)-cavitand 2, encapsulates 1 molecule of guests such as 1,4-diacetoxybenzene 3a, 1,4-diacetoxy-2,5-dimethylbenzene 3b, 1,4-diacetoxy-2,5-dialkoxybenzenes (3c, OCH\n 3<\/jats:sub>\n ; 3d, OC\n 2<\/jats:sub>\n H\n 5<\/jats:sub>\n ; 3e, OC\n 3<\/jats:sub>\n H\n 7<\/jats:sub>\n ; 3f, OC\n 4<\/jats:sub>\n H\n 9<\/jats:sub>\n ; 3g, OC\n 5<\/jats:sub>\n H\n 11<\/jats:sub>\n ; 3h, OC\n 6<\/jats:sub>\n H\n 13<\/jats:sub>\n ; 3i, OC\n 8<\/jats:sub>\n H\n 17<\/jats:sub>\n ), 1,4-diacetoxy-2,5-difluorobenzene 4a, and 1,4-diacetoxy-2,3-difluorobenzene 4b. The X-ray crystallographic analysis of 3c@(1\u00b72) showed that the acetoxy groups at the 1,4-positions of 3c are oriented toward the 2 aromatic cavity ends of 1\u00b72 and that 3c can rotate along the long axis of 1\u00b72. Thus, the 1\u00b72 (stator) with the encapsulation guest (rotator) behaves as a supramolecular gyroscope. A variable temperature (VT)\n 1<\/jats:sup>\n H NMR study in CDCl\n 3<\/jats:sub>\n showed that 3a, 3b, 4a, and 4b within 1\u00b72 rotate rapidly even at 218 K, whereas guest rotation is almost inhibited for 3h and 3i even at 323 K. In this respect, 4b with a large dipole moment is a good candidate for the rotator of 1\u00b72. For 3c\u20133g, the enthalpic (\u0394\n H<\/jats:italic>\n \u2021<\/jats:sup>\n ) and entropic (\u0394\n S<\/jats:italic>\n \u2021<\/jats:sup>\n ) contributions to the free energy of activation (\u0394\n G<\/jats:italic>\n \u2021<\/jats:sup>\n ) for the guest-rotational steric barriers within 1\u00b72 were obtained from Eyring plots based on line-shape analysis of the VT\n 1<\/jats:sup>\n H NMR spectra. The value of \u0394\n G<\/jats:italic>\n \u2021<\/jats:sup>\n increased in the order 3c < 3d < 3e < 3f < 3g. Thus, the elongation of the alkoxy chains at the 2,5-positions of 3 puts the brakes on guest rotation within 1\u00b72.\n <\/jats:p>","DOI":"10.1073\/pnas.0812660106","type":"journal-article","created":{"date-parts":[[2009,5,4]],"date-time":"2009-05-04T21:54:30Z","timestamp":1241474070000},"page":"10444-10448","update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":74,"title":["Encapsulated-guest rotation in a self-assembled heterocapsule directed toward a supramolecular gyroscope"],"prefix":"10.1073","volume":"106","author":[{"given":"Hitomi","family":"Kitagawa","sequence":"first","affiliation":[{"name":"Department of Chemistry, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yasuhiro","family":"Kobori","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Masamichi","family":"Yamanaka","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kenji","family":"Yoza","sequence":"additional","affiliation":[{"name":"Bruker AXS, 3-9-A Moriya, Kanagawa-ku, Yokohama 221-0022, Japan; and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kenji","family":"Kobayashi","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan;"},{"name":"PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[2009,6,30]]},"reference":[{"key":"e_1_3_3_1_2","doi-asserted-by":"publisher","DOI":"10.1021\/cr0300993"},{"key":"e_1_3_3_2_2","doi-asserted-by":"publisher","DOI":"10.1002\/anie.200504313"},{"key":"e_1_3_3_3_2","doi-asserted-by":"publisher","DOI":"10.1021\/ar0680217"},{"key":"e_1_3_3_4_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja039482f"},{"key":"e_1_3_3_5_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.0506183102"},{"key":"e_1_3_3_6_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja00148a008"},{"key":"e_1_3_3_7_2","doi-asserted-by":"publisher","DOI":"10.1039\/b506883e"},{"key":"e_1_3_3_8_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo701552b"},{"key":"e_1_3_3_9_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja0119447"},{"key":"e_1_3_3_10_2","doi-asserted-by":"publisher","DOI":"10.1246\/cl.2007.1076"},{"key":"e_1_3_3_11_2","doi-asserted-by":"publisher","DOI":"10.1021\/ol071379y"},{"key":"e_1_3_3_12_2","doi-asserted-by":"publisher","DOI":"10.1002\/anie.200460534"},{"key":"e_1_3_3_13_2","doi-asserted-by":"publisher","DOI":"10.1002\/anie.200601191"},{"key":"e_1_3_3_14_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.0706117105"},{"key":"e_1_3_3_15_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja046703o"},{"key":"e_1_3_3_16_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja035337q"},{"key":"e_1_3_3_17_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo062563k"},{"key":"e_1_3_3_18_2","doi-asserted-by":"publisher","DOI":"10.1002\/chem.200305570"},{"key":"e_1_3_3_19_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja0465799"},{"key":"e_1_3_3_20_2","volume-title":"The CH\/\u03c0 Interaction","author":"Nishio M","year":"1998","unstructured":"M Nishio, M Hirota, Y Umezawa The CH\/\u03c0 Interaction (Wiley\u2013VCH, New York, 1998)."},{"key":"e_1_3_3_21_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo800677n"},{"key":"e_1_3_3_22_2","doi-asserted-by":"publisher","DOI":"10.1038\/nature04635"},{"key":"e_1_3_3_23_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0079-6565(00)00029-7"},{"key":"e_1_3_3_24_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja037035u"},{"key":"e_1_3_3_25_2","unstructured":"(Wavefunction Inc. Irvine CASpartan '06. (2006)."},{"key":"e_1_3_3_26_2","doi-asserted-by":"publisher","DOI":"10.1039\/b718595b"}],"container-title":["Proceedings of the National Academy of Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.0812660106","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,4,12]],"date-time":"2022-04-12T17:26:45Z","timestamp":1649784405000},"score":1,"resource":{"primary":{"URL":"https:\/\/pnas.org\/doi\/full\/10.1073\/pnas.0812660106"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2009,6,30]]},"references-count":26,"journal-issue":{"issue":"26","published-print":{"date-parts":[[2009,6,30]]}},"alternative-id":["10.1073\/pnas.0812660106"],"URL":"https:\/\/doi.org\/10.1073\/pnas.0812660106","relation":{},"ISSN":["0027-8424","1091-6490"],"issn-type":[{"value":"0027-8424","type":"print"},{"value":"1091-6490","type":"electronic"}],"subject":[],"published":{"date-parts":[[2009,6,30]]},"assertion":[{"value":"2008-12-12","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2009-06-30","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}