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Physicochemical and Electronic Properties of Cationic [6]Helicenes: from Chemical and Electrochemical Stabilities to Far‐Red (Polarized) Luminescence 下载免费PDF全文
Dr. Johann Bosson Geraldine M. Labrador Dr. Simon Pascal Dr. François‐Alexandre Miannay Oleksandr Yushchenko Haidong Li Dr. Laurent Bouffier Prof. Neso Sojic Roberto C. Tovar Prof. Gilles Muller Prof. Denis Jacquemin Dr. Adèle D. Laurent Dr. Boris Le Guennic Prof. Eric Vauthey Prof. Jérôme Lacour 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(51):18394-18403
The physicochemical properties of cationic dioxa ( 1 ), azaoxa ( 2 ), and diaza ( 3 ) [6]helicenes demonstrate a much higher chemical stability of the diaza adduct 3 (pKR+=20.4, =?0.72 V) compared to its azaoxa 2 (pKR+=15.2, =?0.45 V) and dioxa 1 (pKR+=8.8, =?0.12 V) analogues. The fluorescence of these cationic chromophores is established, and ranges from the orange to the far‐red regions. From 1 to 3 , a bathochromic shift of the lowest energy transitions (up to 614 nm in acetonitrile) and an enhancement of the fluorescence quantum yields and lifetimes (up to 31 % and 9.8 ns, respectively, at 658 nm) are observed. The triplet quantum yields and circularly polarized luminescence are also reported. Finally, fine tuning of the optical properties of the diaza [6]helicene core is achieved through selective and orthogonal post‐functionalization reactions (12 examples, compounds 4 – 15 ). The electronic absorption is modulated from the orange to the far‐red spectral range (560–731 nm), and fluorescence is observed from 591 to 755 nm with enhanced quantum efficiency up to 70 % (619 nm). The influence of the peripheral auxochrome substituents is rationalized by first‐principles calculations. 相似文献
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Inside Back Cover: Circularly Polarized Luminescence from Axially Chiral BODIPY DYEmers: An Experimental and Computational Study (Chem. Eur. J. 45/2016) 下载免费PDF全文
Francesco Zinna Dr. Torsten Bruhn Dr. Ciro A. Guido Dr. Johannes Ahrens Prof. Martin Bröring Prof. Lorenzo Di Bari Prof. Gennaro Pescitelli 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(45):16323-16323
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Dr. Kazuteru Usui Nozomi Narita Ryosuke Eto Seika Suzuki Atsushi Yokoo Dr. Kosuke Yamamoto Prof. Dr. Kazunobu Igawa Naoko Iizuka Yuki Mimura Dr. Tomohiro Umeno Shota Matsumoto Dr. Masashi Hasegawa Prof. Dr. Katsuhiko Tomooka Prof. Dr. Yoshitane Imai Prof. Dr. Satoru Karasawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(65):e202202922
Small chiral organic molecules with CD properties are in high demanded due to their potential use in promising electronic and biological applications. Herein, we reveal a system in which the oxidation of a phosphino group to the corresponding phosphine oxide on the inner rim of a helicene derivative induces a CPL response. Laterally π-extended 7,8-dihydro[5]helicenes bearing phosphine and phosphine oxide groups on their inner helical rims (i. e., the C1 position) were synthesized, and their helical structures were unambiguously determined by X-ray crystallography. The photophysical (UV/visible and emission) and chiroptical properties of these compounds were investigated in various solvents. Despite their structural similarities, phosphine oxide showed a significantly better CPL response than phosphine, with a high dissymmetry factor for emission (|glum|=(1.3–1.9)×10−3) that can be attributed to structural changes in the interior of the helicene helix. 相似文献
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Acid/Base‐Triggered Switching of Circularly Polarized Luminescence and Electronic Circular Dichroism in Organic and Organometallic Helicenes 下载免费PDF全文
Nidal Saleh Barry Moore II Monika Srebro Nicolas Vanthuyne Loïc Toupet J. A. Gareth Williams Christian Roussel Kirandeep K. Deol Gilles Muller Jochen Autschbach Jeanne Crassous 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(4):1673-1681
Electronic circular dichroism and circularly polarized luminescence acid/base switching activity has been demonstrated in helicene‐bipyridine proligand 1 a and in its “rollover” cycloplatinated derivative 2 a . Whereas proligand 1 a displays a strong bathochromic shift (>160 nm) of the nonpolarized and circularly polarized luminescence upon protonation, complex 2 a displays slightly stronger emission. This strikingly different behavior between singlet emission in the organic helicene and triplet emission in the organometallic derivative has been rationalized by using quantum‐chemical calculations. The very large bathochromic shift of the emission observed upon protonation of azahelicene‐bipyridine 1 a has been attributed to the decrease in aromaticity (promoting a charge‐transfer‐type transition rather than a π–π* transition) as well as an increase in the HOMO–LUMO character of the transition and stabilization of the LUMO level upon protonation. 相似文献
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Cover Picture: Inherently Chiral Macrocyclic Oligothiophenes: Easily Accessible Electrosensitive Cavities with Outstanding Enantioselection Performances (Chem. Eur. J. 47/2014) 下载免费PDF全文
Prof. Francesco Sannicolò Prof. Patrizia R. Mussini Prof. Tiziana Benincori Dr. Roberto Cirilli Prof. Sergio Abbate Serena Arnaboldi Simone Casolo Dr. Ettore Castiglioni Prof. Giovanna Longhi Dr. Rocco Martinazzo Dr. Monica Panigati Dr. Marco Pappini Dr. Elsa Quartapelle Procopio Dr. Simona Rizzo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(47):15257-15257
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Rocío Ponce Ortiz Dr. Juan Casado Prof. Víctor Hernández Prof. Juan T. López Navarrete Prof. Joseph A. Letizia Dr. Mark A. Ratner Antonio Facchetti Prof. Tobin J. Marks Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(20):4959-4959
Molecular semiconductors in the guise of three diazine‐functionalized oligothiophenes have been synthesized and their structural, optical, vibrational, electrochemical, and semiconductor properties studied. In their Full Paper on page 5023 ff. , J. T. López Navarrete, A. Facchetti, T. J. Marks et al. describe how these diazine‐functionalized oligothiophenes are reasonably efficient hole transporters.
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Inside Cover: Beryllium‐Based Anion Sponges: Close Relatives of Proton Sponges (Chem. Eur. J. 51/2016) 下载免费PDF全文
Oriana Brea Dr. Inés Corral Prof. Dr. Otilia Mó Prof. Dr. Manuel Yáñez Prof. Dr. Ibon Alkorta Prof. Dr. José Elguero 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(51):18270-18270
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Back Cover: Exploring Excited‐State Tunability in Luminescent Tris‐cyclometalated Platinum(IV) Complexes: Synthesis of Heteroleptic Derivatives and Computational Calculations (Chem. Eur. J. 52/2014) 下载免费PDF全文
Fabio Juliá Dr. Gabriel Aullón Dr. Delia Bautista Dr. Pablo González‐Herrero 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(52):17660-17660
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Thioflavin T: Electronic Circular Dichroism and Circularly Polarized Luminescence Induced by Amyloid Fibrils 下载免费PDF全文
Dr. Anna Rybicka Prof. Giovanna Longhi Prof. Ettore Castiglioni Prof. Sergio Abbate Dr. Wojciech Dzwolak Dr. Viktoria Babenko Dr. Magdalena Pecul 《Chemphyschem》2016,17(18):2931-2937
The circularly polarized luminescence (CPL) spectrum of thioflavin T (ThT) bound to insulin amyloid fibrils has been measured for the first time. It has been found that the samples exhibiting induced circular dichroism (CD) retain the optical activity in the CPL spectra, with the same sign of the rotatory strength. The fluorescence dissymmetry factor is substantial (of the order of magnitude 10?2). Unlike in the corresponding CD and absorption spectra, there is no shift of the CPL band with respect to the fluorescence band. It has been verified that the measured CPL spectra are free from artifacts from circularly polarized scattering of emitted light by conducting additional measurements in a medium with a refractive index similar to insulin (methylsalicylate). The CD and CPL spectra have been interpreted by means of density functional calculations carried out for ThT in its ground and first excited states in different dielectric environments and for ThT interacting with an aromatic ring. It has been found that the presence of an aromatic ring close to the ThT molecule induces Cotton effects of the same order of magnitude as the stabilization of one enantiomeric conformer. Thus, it is expected that both mechanisms contribute to the induced CD and CPL effect to a similar degree. 相似文献
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Inside Back Cover: Redox‐Active Tetraruthenium Macrocycles Built from 1,4‐Divinylphenylene‐Bridged Diruthenium Complexes (Chem. Eur. J. 28/2016) 下载免费PDF全文
Stefan Scheerer Dr. Michael Linseis Dr. Evelyn Wuttke Sabrina Weickert Prof. Dr. Malte Drescher Dr. Oliver Tröppner Prof. Dr. Ivana Ivanović‐Burmazović Andreas Irmler Prof. Dr. Fabian Pauly Prof. Dr. Rainer F. Winter 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(28):9843-9843