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A π‐expanded X‐type double [5]helicene comprising dihydropyracylene moieties was synthesized from commercially available acenaphthene. X‐ray crystallographic analysis revealed the unique highly twisted structure of the compound resulting in the occurrence of two enantiomers which were separated by chiral HPLC, owing to their high conformational stability. The compound shows strongly bathochromically shifted UV/vis absorption and emission bands with small Stokes shift and considerable photoluminescence quantum yield and circular polarized luminescence response. The electrochemical studies revealed five facilitated reversible redox events, including three reductions and two oxidations, thus qualifying the compound as chiral multistage redox amphoter. The experimental findings are in line with the computational studies based on density functional theory pointing towards increased spatial extension of the frontier molecular orbitals over the polycyclic framework and a considerably narrowed HOMO–LUMO gap. [ABSTRACT FROM AUTHOR]

Four substituted nonacenes were prepared and characterized by UV‐vis and EPR spectroscopy and X‐ray crystallography. The compounds are the most stable and soluble nonacenes to date – due to six strategically placed triisopropylsilyl(TIPS)‐ethynyl groups. They are stable for several weeks in the solid state. In dilute solution their half‐life is 5–9 h. Crystal structure analyses of two nonacenes prove their structures. A nonacene derivative was tested in a solution‐processed transistor and exhibits ambipolar charge transport (μe=0.007 cm2/Vs; μh=0.023 cm2/Vs). [ABSTRACT FROM AUTHOR]

Herein, we describe a gold‐catalyzed cascade cyclization of Boc‐protected benzylamines bearing two tethered alkyne moieties in a domino reaction initiated by a 6‐endo‐dig cyclization. The reaction was screened intensively, and the scope was explored, resulting in nine new Boc‐protected dihydrobenzo[c]phenanthridines with yields of up to 98 %; even a π‐extension and two bidirectional approaches were successful. Furthermore, thermal cleavage of the Boc group and subsequent oxidation gave substituted benzo[c]phenanthridines in up to quantitative yields. Two bidirectional approaches under the optimized conditions were successful, and the resulting π‐extended molecules were tested as organic semiconductors in organic thin‐film transistors. [ABSTRACT FROM AUTHOR]

Azo compounds, computational chemistry, excitonic coupling, isomerization, photochemistry Keywords: azo compounds; computational chemistry; excitonic coupling; isomerization; photochemistry EN azo compounds computational chemistry excitonic coupling isomerization photochemistry 1 1 1 07/08/22 20220706 NES 220706 B You can't separate this couple b : One of the azo-substituted tripycenes synthesized in this work is highlighted in front of its UV-Vis absorption spectrum. Cover Feature: Azobenzene-Substituted Triptycenes: Understanding the Exciton Coupling of Molecular Switches in Close Proximity (Chem. Eur. J. 38/2022). [Extracted from the article]

Chemiluminescence, fluorescence, mechanochemistry, polymers, sensors Keywords: chemiluminescence; fluorescence; mechanochemistry; polymers; sensors EN chemiluminescence fluorescence mechanochemistry polymers sensors 15823 15823 1 11/19/21 20211117 NES 211117 B As potential analytical tools b for collecting and mapping mechanical information in polymer materials, optical force probes (OFPs) have been developed over the last decade. [Extracted from the article]