Suchergebnisse

A unique rippled nanographene constituted by 52 fused rings is presented in which six out-of-plane motifs are fully fused into a triangular aromatic surface of ca. 2.5 nm size. Three units of an unprecedented fully lateral π-extended octabenzo[5]helicene together with three units of saddle-shaped heptagonal rings are combined in a single structure leading to a well-soluble warped nanographene. The two pairs of possible enantiomers have been isolated and their linear, non-linear and chiroptical properties evaluated, revealing an outstanding quantum yield and brightness values at low energy together with good chiroptical responses both in the absorption and emission ; We acknowledge the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (ERC-2015-STG-677023) and the Ministerio de Economía y Competitividad (MINECO, Spain) (CTQ2015-70283- P, UNGR15-CE-3478, BES-2016-076371 and RyC-2013-12943). E.M. thanks the Fundação para a Ciência e a tecnologia (PTDC/NAN-MAT729317/2017 and PTDC/QUI-QFI/29319/2017). We thank the CSIRC-Alhambra from the University of Granada.

A new family of distorted ribbon-shape nanographenes was designed, synthesized and their optical and electrochemical properties were measured, pointing out an unprecedented correlation between their structural characteristics and their two photon absorption (TPA) responses and electrochemical band gaps. Three nanographene ribbons have been prepared: a seven-membered ring containing nanographene presenting a tropone moiety at the edge, its full-carbon analogue and the purely hexagonal one. We have found that the TPA cross-sections and the electrochemical band gaps of the seven-membered ring containing compounds are higher and lower, respectively, than those of the fully hexagonal polycyclic aromatic hydrocarbon (PAH). Interestingly, the difference between presenting or not the electron withdrawing group, barely changes these parameters compared with those of the nanoribbon without the heptagon. ; -European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (ERC-2015-STG-677023) -Ministerio de Ciencia Innovación y Universidades (PGC2018-101181-B-I00) -Ministerio de Economía y Competitividad (BES-2016-076371 and RyC-2013-12943).