Twisted nanographenes(NGs)are currently attracting a lot of attention owing to their geometrical and electronic structures that differ substantively from conventional planar and nonplanar NGs,while the strategic synth...Twisted nanographenes(NGs)are currently attracting a lot of attention owing to their geometrical and electronic structures that differ substantively from conventional planar and nonplanar NGs,while the strategic synthesis of twisted NGs is still a topic of interest because the products are often interconvertible among unidirectionally,alternatively,or randomly twisted geometries and otherwise obtained as a mixture of them.Herein,we report the conformationally specific synthesis of twisted NGs where the geometry was reinforced by introducing 1,4-dioxane rings at a K-region of a central pyrene core that bears a large contortion.The 1,4-dioxane rings were generated by semi-deprotection,of tetraoxa[4.4.4]propellanes in precursor molecules,which were confirmed to be engaged in forming C-C bonds via a Friedel-Crafts type mechanism.The large contortion within the pyrene core causes a narrowed HOMO-LUMO gap on account of unusual pz-lobe overlap between+z and-z sides,giving rise to red emission with a high quantum yield of 94%as well as stable redox processes of 2e^(-)uptake/release.展开更多
基金provided by the National Natural Science Foundation of China(22161035)the Education Department of Inner Mongolia Autonomous Region(NJYT22089)+2 种基金the Funding Scheme for High-Level Overseas Chinese Students’Return,the International Collaborative Research Program of Institute for Chemical Research(ICR),Kyoto University(2022-39 and 2023-46)JSPS KAKENHI Grant JP22H04538,Advanced Technology Institute Research Grants 2023,ISHIZUE 2024 of Kyoto University,JACI Prize for Encouraging Young Researcher,Yazaki Memorial Foundation for Science and Technology,and the Asahi Glass Foundation.We are grateful to Mr.He Meng,Mr.Yuzhan Jiaosupport of NMR and quantum yield measurements.
文摘Twisted nanographenes(NGs)are currently attracting a lot of attention owing to their geometrical and electronic structures that differ substantively from conventional planar and nonplanar NGs,while the strategic synthesis of twisted NGs is still a topic of interest because the products are often interconvertible among unidirectionally,alternatively,or randomly twisted geometries and otherwise obtained as a mixture of them.Herein,we report the conformationally specific synthesis of twisted NGs where the geometry was reinforced by introducing 1,4-dioxane rings at a K-region of a central pyrene core that bears a large contortion.The 1,4-dioxane rings were generated by semi-deprotection,of tetraoxa[4.4.4]propellanes in precursor molecules,which were confirmed to be engaged in forming C-C bonds via a Friedel-Crafts type mechanism.The large contortion within the pyrene core causes a narrowed HOMO-LUMO gap on account of unusual pz-lobe overlap between+z and-z sides,giving rise to red emission with a high quantum yield of 94%as well as stable redox processes of 2e^(-)uptake/release.
