{"id":84454,"date":"2026-03-18T14:21:38","date_gmt":"2026-03-18T05:21:38","guid":{"rendered":"https:\/\/www.waseda.jp\/inst\/research\/?p=84454"},"modified":"2026-05-18T14:22:59","modified_gmt":"2026-05-18T05:22:59","slug":"tetraaza7-15helicenes-synthesized-by-two-step-strategy-length-controlled-chiral-%cf%80-systems-exhibiting-amplified-circularly-polarized-luminescence%ef%bc%88published-in-angewandte-chemi","status":"publish","type":"post","link":"https:\/\/www.waseda.jp\/inst\/research\/news\/84454","title":{"rendered":"Tetraaza[7]\u2013[15]helicenes Synthesized by Two-Step Strategy: Length-Controlled Chiral \u03c0-Systems Exhibiting Amplified Circularly Polarized Luminescence\uff08Published in Angewandte Chemie – International Edition, March, 2026\uff09"},"content":{"rendered":"\n\n\n\n\n\n\n\n\n
Journal Title
\n\/\u63b2\u8f09\u30b8\u30e3\u30fc\u30ca\u30eb\u540d<\/td>\n		Angewandte Chemie – International Edition<\/td>\n<\/tr>\n
Publication Year and Month
\n\/\u63b2\u8f09\u5e74\u6708<\/td>\n		March, 2026<\/td>\n<\/tr>\n
Paper Title
\n\/\u8ad6\u6587\u30bf\u30a4\u30c8\u30eb<\/td>\n		Tetraaza[7]\u2013[15]helicenes Synthesized by Two-Step Strategy: Length-Controlled Chiral \u03c0-Systems Exhibiting Amplified Circularly Polarized Luminescence<\/td>\n<\/tr>\n
DOI
\n\/\u8ad6\u6587DOI<\/td>\n		10.1002\/anie.202524463<\/a><\/td>\n<\/tr>\n
\u00a0Author of Waseda University
\n\/\u672c\u5b66\u306e\u8457\u8005<\/td>\n		SHIBATA, Takanori(Professor, Faculty of Science and Engineering, School of Advanced Science and Engineering):Correspoinding Author,\u00a0 Last Author<\/span><\/span><\/td>\n<\/tr>\n
Related Websites
\n\/\u95a2\u9023Web<\/td>\n		–<\/td>\n<\/tr>\n
Abstract
\n\/\u6284\u9332<\/td>\n		\n
\n

Helicenes are chiral \u03c0-conjugated molecules whose properties strongly depend on their lengths. Systematic studies of these compounds have been limited by synthetic challenges. Here we report a concise two-step strategy (defined as the helicene-forming sequence from aminohelicene precursors) to access a homologous series of tetraaza[7]\u2013[15]helicenes. Optical spectra converge beyond [11]H, defining a conjugation ceiling, while chiroptical responses amplify sharply, yielding |g<\/i>lum<\/sub>| up to 0.028. Fluorescence quantum yields show a nonmonotonic dependence, with [7]H and [15]H maintaining both high\u00a0\u03a6<\/i>F<\/sub>\u00a0(0.39 and 0.36) and large |g<\/i>lum<\/sub>|, resulting in outstanding, albeit semi-quantitative, CPL performance, with figures of merit reaching 0.010 and CPL brightness values of approximately 490. TD-DFT calculations attribute this amplification to the delayed alignment of electric and magnetic transition dipoles, while\u00a01<\/sup>H NMR shifts of inner protons provide an independent probe of structural reorganization within the helical cavity. Additionally, experiment and theory have consistently identified [11]H as the critical helicene length at which the framework undergoes a qualitative transition. Notably, the [15]helicene constitutes the longest helicene ever resolved into its enantiomers, underscoring the synthetic power of this modular approach. Importantly, our synthetic route is effective for constructing higher-order helicenes, offering a generalizable platform for length-controlled, heteroatom-containing helicenes. These findings establish long tetraazahelicenes as a rare platform where through-bond conjugation and through-space orbital coupling act cooperatively to govern photophysical and chiroptical properties.<\/p>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"excerpt":{"rendered":"

Journal Title \/\u63b2\u8f09\u30b8\u30e3\u30fc\u30ca\u30eb\u540d Angewandte Chemie – International Edition Publication Year and Month \/\u63b2\u8f09\u5e74\u6708 March […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[],"tags":[218,217],"class_list":["post-84454","post","type-post","status-publish","format-standard","hentry","tag-impact-en","tag-impact"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.waseda.jp\/inst\/research\/wp-json\/wp\/v2\/posts\/84454","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.waseda.jp\/inst\/research\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.waseda.jp\/inst\/research\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.waseda.jp\/inst\/research\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.waseda.jp\/inst\/research\/wp-json\/wp\/v2\/comments?post=84454"}],"version-history":[{"count":1,"href":"https:\/\/www.waseda.jp\/inst\/research\/wp-json\/wp\/v2\/posts\/84454\/revisions"}],"predecessor-version":[{"id":84458,"href":"https:\/\/www.waseda.jp\/inst\/research\/wp-json\/wp\/v2\/posts\/84454\/revisions\/84458"}],"wp:attachment":[{"href":"https:\/\/www.waseda.jp\/inst\/research\/wp-json\/wp\/v2\/media?parent=84454"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.waseda.jp\/inst\/research\/wp-json\/wp\/v2\/categories?post=84454"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.waseda.jp\/inst\/research\/wp-json\/wp\/v2\/tags?post=84454"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}