{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,27]],"date-time":"2026-09-27T13:30:07Z","timestamp":1790515807447,"version":"4.1.0"},"reference-count":75,"publisher":"Wiley","issue":"40","license":[{"start":{"date-parts":[[2012,8,22]],"date-time":"2012-08-22T00:00:00Z","timestamp":1345593600000},"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":[[2012,10]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>A new class of propel\u2010 ler\u2010shaped compound (<jats:bold>4<\/jats:bold>), which consisted of dehydrobenzo[14]annulene ([14]DBA) blades, as well as its naphtho homologues (<jats:bold>5<\/jats:bold> and <jats:bold>6<\/jats:bold>), have been prepared. Although NMR studies of compound <jats:bold>4<\/jats:bold> did not provide useful information regarding its conformation in solution, DFT calculations with different functionals and the 6\u201031G* basis set all indicated that the <jats:italic>D<\/jats:italic><jats:sub>3<\/jats:sub>\u2010symmetric structure was energetically more favorable than the <jats:italic>C<\/jats:italic><jats:sub>2<\/jats:sub> conformer. From X\u2010ray crystallographic analysis, it appeared that compound <jats:bold>4<\/jats:bold> adopted a propeller\u2010shaped\u2010, approximately <jats:italic>D<\/jats:italic><jats:sub>3<\/jats:sub>\u2010symmetric structure in the solid state, in which the [14]DBA blades were twisted substantially owing to steric repulsion between the neighboring benzene rings. On the contrary, in the case of compound <jats:bold>6<\/jats:bold>, although the DFT calculations with the B3LYP functional predicted that the <jats:italic>D<\/jats:italic><jats:sub>3<\/jats:sub>\u2010symmetric conformation was more stable, calculations with the M05 and M05\u20102X functionals indicated that the <jats:italic>C<\/jats:italic><jats:sub>2<\/jats:sub> conformer was more favorable because of \u03c0\u2013\u03c0 interactions between the naphthalene units of a pair of neighboring blades. Indeed, X\u2010ray analysis of compound <jats:bold>6<\/jats:bold> showed that it adopted an approximately <jats:italic>C<\/jats:italic><jats:sub>2<\/jats:sub>\u2010symmetric conformation. Moreover, on the basis of variable\u2010temperature <jats:sup>1<\/jats:sup>H\u2005NMR measurements, we found that compound <jats:bold>6<\/jats:bold> adopted a <jats:italic>C<\/jats:italic><jats:sub>2<\/jats:sub> conformation and the barrier for interconversion between the <jats:italic>C<\/jats:italic><jats:sub>2<\/jats:sub>\u2013<jats:italic>C<\/jats:italic><jats:sub>2<\/jats:sub> conformers was estimated to be 16.2\u2005kcal\u2009mol<jats:sup>\u22121<\/jats:sup>; however, no indication of the presence of the <jats:italic>D<\/jats:italic><jats:sub>3<\/jats:sub> isomer was obtained. The relatively small energy barriers to interconversion, despite the large overlapping of neighboring blades, was ascribed to the flexibility of the acetylene linkages, which could be deformed substantially in the transition state of the ring\u2010flip.<\/jats:p>","DOI":"10.1002\/chem.201201061","type":"journal-article","created":{"date-parts":[[2012,8,22]],"date-time":"2012-08-22T15:47:34Z","timestamp":1345650454000},"page":"12814-12824","source":"Crossref","is-referenced-by-count":26,"title":["Molecular Propellers that Consist of Dehydrobenzo[14]annulene Blades"],"prefix":"10.1002","volume":"18","author":[{"given":"Shunpei","family":"Nobusue","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuichi","family":"Mukai","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yo","family":"Fukumoto","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rui","family":"Umeda","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kazukuni","family":"Tahara","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Motohiro","family":"Sonoda","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yoshito","family":"Tobe","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2012,8,22]]},"reference":[{"key":"e_1_2_6_1_2","doi-asserted-by":"publisher","DOI":"10.1021\/cr050550l"},{"key":"e_1_2_6_2_2","unstructured":"\u00a0"},{"key":"e_1_2_6_3_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0022-1139(00)82681-0"},{"key":"e_1_2_6_4_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0022-2860(96)09597-X"},{"key":"e_1_2_6_5_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja074120j"},{"key":"e_1_2_6_6_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja983471i"},{"key":"e_1_2_6_7_2","unstructured":"\u00a0"},{"key":"e_1_2_6_8_2","doi-asserted-by":"publisher","DOI":"10.1021\/ol990864t"},{"key":"e_1_2_6_9_2","doi-asserted-by":"publisher","DOI":"10.1021\/ol005916p"},{"key":"e_1_2_6_10_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0022-328X(02)01667-4"},{"key":"e_1_2_6_11_2","doi-asserted-by":"publisher","DOI":"10.1002\/chem.200600466"},{"key":"e_1_2_6_12_2","doi-asserted-by":"publisher","DOI":"10.1002\/ange.201104935"},{"key":"e_1_2_6_12_3","doi-asserted-by":"publisher","DOI":"10.1002\/anie.201104935"},{"key":"e_1_2_6_13_2","unstructured":"\u00a0"},{"key":"e_1_2_6_14_2","doi-asserted-by":"publisher","DOI":"10.1016\/0040-4039(96)01933-8"},{"key":"e_1_2_6_15_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.281.5376.531"},{"key":"e_1_2_6_16_2","doi-asserted-by":"publisher","DOI":"10.1055\/s-2002-20473"},{"key":"e_1_2_6_17_2","doi-asserted-by":"publisher","DOI":"10.1002\/ange.201105105"},{"key":"e_1_2_6_17_3","doi-asserted-by":"publisher","DOI":"10.1002\/anie.201105105"},{"key":"e_1_2_6_18_2","doi-asserted-by":"publisher","DOI":"10.1021\/ol060781u"},{"key":"e_1_2_6_19_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo0622781"},{"key":"e_1_2_6_20_2","unstructured":"For previous syntheses of [14]DBA and its derivatives see:"},{"key":"e_1_2_6_21_2","first-page":"1216","author":"Baldwin K. P.","year":"1995","journal-title":"Synlett"},{"key":"e_1_2_6_22_2","doi-asserted-by":"publisher","DOI":"10.1002\/ange.200353043"},{"key":"e_1_2_6_22_3","doi-asserted-by":"publisher","DOI":"10.1002\/anie.200353043"},{"key":"e_1_2_6_23_2","unstructured":"\u00a0"},{"key":"e_1_2_6_24_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0040-4020(01)00232-0"},{"key":"e_1_2_6_25_2","doi-asserted-by":"publisher","DOI":"10.1246\/bcsj.78.917"},{"key":"e_1_2_6_26_2","doi-asserted-by":"publisher","DOI":"10.1021\/cr1000628"},{"key":"e_1_2_6_27_2","doi-asserted-by":"publisher","DOI":"10.1021\/ol101542e"},{"key":"e_1_2_6_28_2","unstructured":"\u00a0"},{"key":"e_1_2_6_29_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0040-4020(01)89821-5"},{"key":"e_1_2_6_30_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja00090a066"},{"key":"e_1_2_6_31_2","unstructured":"About one\u2010sixth of the volume of an eluent from GPC analysis that contained purified compound4was evaporated to dryness the residue was weighed and its purity was checked by NMR spectroscopy. From this experiment the yield of compound4was estimated to be approximately 24\u2009% by using CHBr3as an internal standard."},{"key":"e_1_2_6_32_2","unstructured":"\u00a0"},{"key":"e_1_2_6_33_2","doi-asserted-by":"publisher","DOI":"10.1002\/ange.19860980319"},{"key":"e_1_2_6_33_3","doi-asserted-by":"publisher","DOI":"10.1002\/anie.198602681"},{"key":"e_1_2_6_34_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo00246a018"},{"key":"e_1_2_6_35_2","doi-asserted-by":"publisher","DOI":"10.1021\/ol016274o"},{"key":"e_1_2_6_36_2","unstructured":"Several hexaethynylbenzene derivatives have been prepared by substitution with compound12 see:"},{"key":"e_1_2_6_37_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja0209262"},{"key":"e_1_2_6_38_2","doi-asserted-by":"publisher","DOI":"10.1002\/ejoc.200300644"},{"key":"e_1_2_6_39_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja069025"},{"key":"e_1_2_6_40_2","doi-asserted-by":"publisher","DOI":"10.1039\/b718185j"},{"key":"e_1_2_6_41_2","unstructured":"\u00a0"},{"key":"e_1_2_6_42_2","doi-asserted-by":"publisher","DOI":"10.1063\/1.2126975"},{"key":"e_1_2_6_43_2","doi-asserted-by":"publisher","DOI":"10.1021\/ct0502763"},{"key":"e_1_2_6_44_2","doi-asserted-by":"publisher","DOI":"10.1021\/ct060044j"},{"key":"e_1_2_6_45_2","doi-asserted-by":"publisher","DOI":"10.1246\/bcsj.82.931"},{"key":"e_1_2_6_46_2","unstructured":"For a [14]DBA ring \u201cspoke\u201d bond angles of 168\u2013172\u00b0 have been reported; see:"},{"key":"e_1_2_6_47_2","doi-asserted-by":"publisher","DOI":"10.1055\/s-1995-5247"},{"key":"e_1_2_6_48_2","doi-asserted-by":"publisher","DOI":"10.1021\/ol0514552"},{"key":"e_1_2_6_49_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0040-4020(00)00932-7"},{"key":"e_1_2_6_50_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo800225u"},{"key":"e_1_2_6_51_2","unstructured":"\u00a0"},{"key":"e_1_2_6_52_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo010183n"},{"key":"e_1_2_6_53_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo0615697"},{"key":"e_1_2_6_54_2","unstructured":"\u00a0"},{"key":"e_1_2_6_55_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo00085a016"},{"key":"e_1_2_6_56_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo047857p"},{"key":"e_1_2_6_57_2","unstructured":"Another dihedral angle between the mean planes of two almost\u2010planar butadiyne\u2010bridged naphthalene rings in ring\u2005E (i.e. C34\uf8ffC43 versus C48\uf8ffC57) was 1.8\u00b0."},{"key":"e_1_2_6_58_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja020595t"},{"key":"e_1_2_6_59_2","unstructured":"\u00a0"},{"key":"e_1_2_6_60_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo900482q"},{"key":"e_1_2_6_61_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo200513q"},{"key":"e_1_2_6_62_2","doi-asserted-by":"publisher","DOI":"10.1063\/1.1480445"},{"key":"e_1_2_6_63_2","unstructured":"\u00a0"},{"key":"e_1_2_6_64_2","doi-asserted-by":"publisher","DOI":"10.1039\/b808881k"},{"key":"e_1_2_6_65_2","doi-asserted-by":"publisher","DOI":"10.1021\/cr8005558"},{"key":"e_1_2_6_66_2","unstructured":"The latter behavior can be attributed to the change in the ratio of the conformational population. As shown in the Supporting Information Table\u2005S3 for both compounds4and5 the calculated chemical shifts of theD3structure are shifted downfield compared to those of theC2structure. Hence upon lowering the temperature the observed downfield shifts are presumably due to the population of the more\u2010stableD3conformers."},{"key":"e_1_2_6_67_2","unstructured":"\u00a0"},{"key":"e_1_2_6_68_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja107314p"},{"key":"e_1_2_6_69_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1108170108"},{"key":"e_1_2_6_70_2","unstructured":"Because of the instability of the material the melting point was not determined."},{"key":"e_1_2_6_71_2","unstructured":"Compound6was barely soluble in any solvent and was only slightly soluble in aromatic solvents such as toluene andp\u2010dichlorobenzene at elevated temperature. The13C\u2005NMR spectrum of compound6is not reported because the intensities of the signal were low and most of the signals overlapped with the signals of the aromatic solvent and hence were concealed by them."}],"container-title":["Chemistry \u2013 A European Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1002%2Fchem.201201061","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/chemistry-europe.onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/chem.201201061","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T21:34:34Z","timestamp":1760304874000},"score":1,"resource":{"primary":{"URL":"https:\/\/chemistry-europe.onlinelibrary.wiley.com\/doi\/10.1002\/chem.201201061"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2012,8,22]]},"references-count":75,"journal-issue":{"issue":"40","published-print":{"date-parts":[[2012,10]]}},"alternative-id":["10.1002\/chem.201201061"],"URL":"https:\/\/doi.org\/10.1002\/chem.201201061","archive":["Portico"],"relation":{},"ISSN":["0947-6539","1521-3765"],"issn-type":[{"value":"0947-6539","type":"print"},{"value":"1521-3765","type":"electronic"}],"subject":[],"published":{"date-parts":[[2012,8,22]]}}}