{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,19]],"date-time":"2026-02-19T03:36:30Z","timestamp":1771472190401,"version":"3.50.1"},"reference-count":47,"publisher":"Wiley","issue":"33","license":[{"start":{"date-parts":[[2026,6,11]],"date-time":"2026-06-11T00:00:00Z","timestamp":1781136000000},"content-version":"am","delay-in-days":347,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#am"},{"start":{"date-parts":[[2025,6,29]],"date-time":"2025-06-29T00:00:00Z","timestamp":1751155200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"funder":[{"DOI":"10.13039\/501100002241","name":"Japan Science and Technology Agency","doi-asserted-by":"publisher","award":["JPMJFR211M"],"award-info":[{"award-number":["JPMJFR211M"]}],"id":[{"id":"10.13039\/501100002241","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Angew Chem Int Ed"],"published-print":{"date-parts":[[2025,8,11]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>\n                    [\n                    <jats:italic>n<\/jats:italic>\n                    ]Cycloparaphenylene ketone\n                    <jats:bold>4<\/jats:bold>\n                    , [\n                    <jats:italic>n<\/jats:italic>\n                    ]CPP\u2010CO, in which a carbonyl group is inserted into [\n                    <jats:italic>n<\/jats:italic>\n                    ]CPP framework, with\n                    <jats:italic>n<\/jats:italic>\n                    \u00a0=\u00a06, 7, 8, and 10, was synthesized by a coupling reaction between a CPP precursor and a ketone unit, followed by reductive aromatization. Single crystal X\u2010ray diffraction analysis and density functional theory (DFT) calculations confirmed their M\u00f6bius topology and significant molecular strain as characterized by the deviations in bond angles at the carbonyl carbon. The strain was also evidenced by size\u2010dependent 20\u201350 cm\n                    <jats:sup>\u22121<\/jats:sup>\n                    shifts in the carbonyl IR stretching bands. The CPP units in\n                    <jats:bold>4<\/jats:bold>\n                    significantly alter the electronic properties, particularly the relative orbital energies. Due to the elevation of the energy level of the occupied \u03c0\u2010orbitals by CPP units, the highest occupied molecular orbital (HOMO) in\n                    <jats:bold>4<\/jats:bold>\n                    is the conjugated \u03c0\u2010system, in contrast to benzophenone, where the HOMO is the non\u2010bonding n\u2010orbital. Consequently, the lowest excited state of\n                    <jats:bold>4<\/jats:bold>\n                    is the singlet state (S\n                    <jats:sub>1<\/jats:sub>\n                    ) with \u03c0\u2013\u03c0* character rather than the conventional n\u2013\u03c0* triplet (T\n                    <jats:sub>1<\/jats:sub>\n                    ) state. Furthermore, intersystem crossing from the S\n                    <jats:sub>1<\/jats:sub>\n                    state to the T\n                    <jats:sub>1<\/jats:sub>\n                    state, which is a characteristic process for typical aromatic ketones, does not occur efficiently. As a result,\n                    <jats:bold>4<\/jats:bold>\n                    exhibits unique photophysical properties opposite to those of typical aromatic ketones, such as fluorescing but not phosphorescing. Furthermore, the S\n                    <jats:sub>1<\/jats:sub>\n                    state of\n                    <jats:bold>4<\/jats:bold>\n                    was quenched by molecular oxygen, most likely by the energy exchange mechanism. Optical and electrochemical properties showed a clear dependence on ring size, with smaller rings exhibiting greater strain, lower oxidation potentials, and red\u2010shifted absorption and emission. These findings highlight the unique interplay between molecular topology, strain, and photophysics in CPP\u2010based ketones and provide a foundation for designing novel \u03c0\u2010conjugated materials with tailored excited\u2010state properties.\n                  <\/jats:p>","DOI":"10.1002\/anie.202509754","type":"journal-article","created":{"date-parts":[[2025,6,11]],"date-time":"2025-06-11T10:40:07Z","timestamp":1749638407000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Synthesis and Physical Properties of [\n                    <i>n<\/i>\n                    ]Cycloparaphenylene Ketone (\n                    <i>n<\/i>\n                    \u00a0=\u00a06, 7, 8, and 10)"],"prefix":"10.1002","volume":"64","author":[{"given":"Eiichi","family":"Kayahara","sequence":"first","affiliation":[{"name":"Institute for Chemical Research Kyoto University  Uji Kyoto 611\u20100011 Japan"},{"name":"Department of Chemistry, Graduate School of Advanced Science and Engineering Hiroshima University  Higashi\u2010Hiroshima Hiroshima 739\u20138526 Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ryota","family":"Okahara","sequence":"additional","affiliation":[{"name":"Institute for Chemical Research Kyoto University  Uji Kyoto 611\u20100011 Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Amiri","family":"Shibata","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Graduate School of Advanced Science and Engineering Hiroshima University  Higashi\u2010Hiroshima Hiroshima 739\u20138526 Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Manabu","family":"Abe","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Graduate School of Advanced Science and Engineering Hiroshima University  Higashi\u2010Hiroshima Hiroshima 739\u20138526 Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4112-7249","authenticated-orcid":false,"given":"Shigeru","family":"Yamago","sequence":"additional","affiliation":[{"name":"Institute for Chemical Research Kyoto University  Uji Kyoto 611\u20100011 Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2025,6,29]]},"reference":[{"key":"e_1_2_8_1_1","doi-asserted-by":"publisher","DOI":"10.1021\/acs.chemrev.6b00342"},{"key":"e_1_2_8_2_1","doi-asserted-by":"publisher","DOI":"10.1021\/ar300054e"},{"key":"e_1_2_8_3_1","doi-asserted-by":"publisher","DOI":"10.1002\/cber.19841170236"},{"key":"e_1_2_8_4_1","doi-asserted-by":"publisher","DOI":"10.1021\/ja00198a059"},{"key":"e_1_2_8_5_1","doi-asserted-by":"publisher","DOI":"10.1002\/anie.201806591"},{"key":"e_1_2_8_6_1","doi-asserted-by":"publisher","DOI":"10.1021\/ar5004253"},{"key":"e_1_2_8_7_1","doi-asserted-by":"publisher","DOI":"10.1021\/ar300055x"},{"key":"e_1_2_8_8_1","doi-asserted-by":"publisher","DOI":"10.1002\/tcr.201300035"},{"key":"e_1_2_8_9_1","doi-asserted-by":"publisher","DOI":"10.1021\/jacs.9b06197"},{"key":"e_1_2_8_10_1","doi-asserted-by":"publisher","DOI":"10.1002\/anie.202208591"},{"key":"e_1_2_8_11_1","doi-asserted-by":"publisher","DOI":"10.1002\/anie.202214960"},{"key":"e_1_2_8_12_1","doi-asserted-by":"publisher","DOI":"10.1021\/ja2020668"},{"key":"e_1_2_8_13_1","doi-asserted-by":"publisher","DOI":"10.1039\/c2cp42712e"},{"key":"e_1_2_8_14_1","doi-asserted-by":"publisher","DOI":"10.1039\/c2ob25199j"},{"key":"e_1_2_8_15_1","doi-asserted-by":"publisher","DOI":"10.1002\/anie.201306881"},{"key":"e_1_2_8_16_1","doi-asserted-by":"publisher","DOI":"10.1002\/anie.201301226"},{"key":"e_1_2_8_17_1","doi-asserted-by":"publisher","DOI":"10.1021\/jz5009054"},{"key":"e_1_2_8_18_1","doi-asserted-by":"publisher","DOI":"10.1021\/ja511320f"},{"key":"e_1_2_8_19_1","doi-asserted-by":"publisher","DOI":"10.1021\/jacs.5b09596"},{"key":"e_1_2_8_20_1","doi-asserted-by":"publisher","DOI":"10.1021\/jacs.5b10855"},{"key":"e_1_2_8_21_1","doi-asserted-by":"publisher","DOI":"10.1002\/asia.201600582"},{"key":"e_1_2_8_22_1","doi-asserted-by":"publisher","DOI":"10.1021\/acs.jpca.8b03105"},{"key":"e_1_2_8_23_1","doi-asserted-by":"publisher","DOI":"10.1039\/C8CC03693D"},{"key":"e_1_2_8_24_1","doi-asserted-by":"publisher","DOI":"10.1002\/anie.201102302"},{"key":"e_1_2_8_25_1","doi-asserted-by":"publisher","DOI":"10.1002\/chem.201302694"},{"key":"e_1_2_8_26_1","doi-asserted-by":"publisher","DOI":"10.1002\/chem.201403879"},{"key":"e_1_2_8_27_1","doi-asserted-by":"publisher","DOI":"10.1002\/anie.201311268"},{"key":"e_1_2_8_28_1","doi-asserted-by":"publisher","DOI":"10.1021\/jacs.6b05474"},{"key":"e_1_2_8_29_1","doi-asserted-by":"publisher","DOI":"10.1038\/s41570-019-0140-0"},{"key":"e_1_2_8_30_1","doi-asserted-by":"publisher","DOI":"10.1021\/jacs.1c03240"},{"key":"e_1_2_8_31_1","doi-asserted-by":"publisher","DOI":"10.1021\/acs.orglett.3c00127"},{"key":"e_1_2_8_32_1","doi-asserted-by":"publisher","DOI":"10.1002\/chem.201406650"},{"key":"e_1_2_8_33_1","doi-asserted-by":"publisher","DOI":"10.1002\/chem.201605011"},{"key":"e_1_2_8_34_1","doi-asserted-by":"publisher","DOI":"10.1107\/S0108768100000355"},{"key":"e_1_2_8_35_1","doi-asserted-by":"publisher","DOI":"10.1002\/chem.201605011"},{"key":"e_1_2_8_36_1","doi-asserted-by":"publisher","DOI":"10.1107\/S010876731109204X"},{"key":"e_1_2_8_37_1","doi-asserted-by":"publisher","DOI":"10.1039\/jr9580000642"},{"key":"e_1_2_8_38_1","doi-asserted-by":"publisher","DOI":"10.1021\/cr60240a004"},{"key":"e_1_2_8_39_1","first-page":"107","volume-title":"Handbook of Photochemistry","author":"Murov S. L.","year":"1993"},{"key":"e_1_2_8_40_1","doi-asserted-by":"publisher","DOI":"10.1246\/bcsj.20150230"},{"key":"e_1_2_8_41_1","doi-asserted-by":"publisher","DOI":"10.1364\/OL.41.001498"},{"key":"e_1_2_8_42_1","doi-asserted-by":"publisher","DOI":"10.1021\/acs.jpca.9b09846"},{"key":"e_1_2_8_43_1","doi-asserted-by":"publisher","DOI":"10.1021\/jacs.1c01329"},{"key":"e_1_2_8_44_1","doi-asserted-by":"publisher","DOI":"10.1002\/chem.202301009"},{"key":"e_1_2_8_45_1","doi-asserted-by":"publisher","DOI":"10.1021\/cr010371d"},{"key":"e_1_2_8_46_1","doi-asserted-by":"publisher","DOI":"10.26434\/chemrxiv\u20102025\u2010h3lv9"},{"key":"e_1_2_8_47_1","unstructured":"This data was provided free of charge by the joint Cambridge Crystallographic Data Centre and Fachinformationszentrum Karlsruhe Access Structures service."}],"container-title":["Angewandte Chemie International Edition"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/am-pdf\/10.1002\/anie.202509754","content-type":"application\/pdf","content-version":"am","intended-application":"syndication"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/anie.202509754","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,12,1]],"date-time":"2025-12-01T14:53:55Z","timestamp":1764600835000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/anie.202509754"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,6,29]]},"references-count":47,"journal-issue":{"issue":"33","published-print":{"date-parts":[[2025,8,11]]}},"alternative-id":["10.1002\/anie.202509754"],"URL":"https:\/\/doi.org\/10.1002\/anie.202509754","archive":["Portico"],"relation":{},"ISSN":["1433-7851","1521-3773"],"issn-type":[{"value":"1433-7851","type":"print"},{"value":"1521-3773","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,6,29]]},"assertion":[{"value":"2025-05-03","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-06-11","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-06-29","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e202509754"}}