Organic Letters, Год журнала: 2024, Номер 26(44), С. 9486 - 9491
Опубликована: Окт. 28, 2024
Three novel azatwistarenes 5a, 8, and 13 have been synthesized via the Povarov reaction fully characterized. All of enantiomers were separated using chiral high-performance liquid chromatography, their optical properties investigated through circular dichroism circularly polarized luminescence spectra. In addition, such desired a positive response to acid in dichloromethane.
Язык: Английский
Journal of the American Chemical Society, Год журнала: 2024, Номер 146(23), С. 16161 - 16172
Опубликована: Май 9, 2024
Introducing helical subunits into negatively curved π-systems has a significant effect on both the molecular geometry and photophysical properties; however, synthesis of these embedded with nonbenzenoid remains challenging due to high strain deriving from curvature helix. Here, we report family nonalternant nanographenes containing nitrogen (N)-doped cyclopenta[ef]heptalene unit. Among them, CPH-2 CPH-3 can be viewed as hybrids benzoannulated aza[7]helicene. The crystal structures revealed saddle for CPH-1, saddle-helix hybrid CPH-2, twist-helix CPH-3. Experimental measurements theoretical calculations indicate that moieties in CPHs undergo flexible conformational changes at room temperature, while aza[7]helicene subunit exhibits dramatically increased racemization energy barrier (78.2 kcal mol–1 143.2 CPH-3). combination lone electron pairs N-doped unit twisted helix fragments results rich photophysics distinctive fluorescence phosphorescence CPH-1 similar Both enantiopure display distinct circular dichroism (CD) signals UV–vis range. Notably, compared reported fully π-extended nanographenes, excellent chiroptical properties |gabs| value 1.0 × 10–2 |glum| 7.0 10–3; values are among highest nanographenes.
Язык: Английский
Процитировано
15
Precision Chemistry, Год журнала: 2024, Номер 2(9), С. 488 - 494
Опубликована: Авг. 13, 2024
Multiple helicenes display distinct aromatic cores characterized by highly twisted rings that are shared or fused with constituent helicene moieties. Diversifying these unlocks avenues for creating multiple properties and topologies. Herein we report the synthesis of a quadruple[6]helicene featuring pyrene as core. The involved key steps annulative π-extension reaction Scholl reaction. By extending along axial direction, degree contortion core can be controlled from nearly flat to twisted. Notably, exhibits significant red-shift 0.49 eV compared quadruple[4]helicenes, which arises both augmented effective conjugation due enhanced twisting. Quantum chemical calculations demonstrate in adeptly governs energy levels HOMO LUMO, offers an alternative strategy beyond mere enlargement π backbone. An intriguing serendipitous finding reveals formation one-molecule-thick supramolecular homochiral nanosheets through self-interlocking interactions enantiomers single crystals, rare packing motif helicenes.
Язык: Английский
Процитировано
4
Angewandte Chemie International Edition, Год журнала: 2024, Номер unknown
Опубликована: Окт. 31, 2024
Herein, corannulene-based quintuple [6]helicenes (Q[6]H-1 and Q[6]H-2) [7]helicene (Q[7]H) were synthesized via penta-fold Heck Mallory reaction. Notably, Q[7]H represents the highest reported helicene based on corannulene. X-ray crystallography reveals that Q[6]H-2 adopts a propeller-shaped conformation with well-preserved corannulene core, while Q[6]H-1 exhibit quasi-propeller-shaped conformations. Upon heating, conformer undergoes conversion to thermodynamically more stable Q[6]H-2, whereas remains unchanged due larger steric congestion. Racemization of enantiomer conformational observed simultaneously at elevated temperature, DFT studies indicating racemization barrier 32.06 kcal ⋅ mol
Язык: Английский
Процитировано
3
Organic Letters, Год журнала: 2025, Номер unknown
Опубликована: Март 28, 2025
A quadruple helicene with a cyclooctatetrapyrrole core was synthesized via simple Ullmann reaction. Its single-crystal structure exhibits saddle shape. The compound shows fluorescence emission λem = 575 nm and good chiroptical properties, including dissymmetric absorption factor (|gabs|) of 5.84 × 10–3 (|glum|) 1.21 10–2.
Язык: Английский
Процитировано
0
Chemical Society Reviews, Год журнала: 2025, Номер unknown
Опубликована: Янв. 1, 2025
Chiral nanographenes: molecular architecture, key constituents, and their circularly polarized luminescence.
Язык: Английский
Процитировано
0
Organic Letters, Год журнала: 2025, Номер unknown
Опубликована: Май 2, 2025
Double [8]helicene 1, featuring a dibenzo[g,p]chrysene core, was synthesized via the Scholl reaction, and its structure unambiguously confirmed by single-crystal X-ray diffraction analysis of dicationic salt [1-Cl]2+·(SbCl6-)2. The compound exhibits red fluorescence with an emission maximum at 618 nm (λem) quantum yield 16.2%, highlighting potential in optoelectronic applications. Furthermore, circular dichroism (CD) circularly polarized luminescence (CPL) measurements reveal notable chiroptical activity, absorption dissymmetry factors |gabs| = 5.11 × 10-3 |glum| 7.1 10-4, respectively.
Язык: Английский
Процитировано
0
Angewandte Chemie International Edition, Год журнала: 2024, Номер unknown
Опубликована: Июль 19, 2024
Abstract Heteroatom‐embedded helical nanographenes (NGs) constitute an important and appealing class of intrinsically chiral materials. In this work, a series B,N‐embedded NGs (BN‐HNGs) bearing azepines was synthesized via stepwise regioselective cyclodehydrogenation. First, the phenyl‐ or nitrogen‐bridged dimers were efficiently clipped into highly congested model compounds 1 2 . Later, controllable Scholl reactions tetraphenyl‐tethered precursor generated 1, 7 8 new C−C bonds, thereby establishing robust method for preparation nonalternant BN‐HNGs with up to 31 fused rings. The bilayer nature unambiguously verified by X‐ray diffraction analysis. chirality transferred stereogenic boron centers upon fluoride coordination, concave‐concave structure comply skeleton. Notably, largest BN‐HNG ( 6 ) spontaneously resolved homochiral 4 helix as molecular spiral staircase during crystallization conglomerate formation at single‐crystal scale. large twisted C ‐symmetric π‐surface dynamic skeleton induced curved might have synergistic effects on self‐recognition enantiomers achieve intriguing spontaneous resolution behavior. chiroptical properties enantiomer further investigated, revealing that had strong response in visible range (400–700 nm).
Язык: Английский
Процитировано
3
Angewandte Chemie, Год журнала: 2024, Номер 136(42)
Опубликована: Июль 19, 2024
Abstract Heteroatom‐embedded helical nanographenes (NGs) constitute an important and appealing class of intrinsically chiral materials. In this work, a series B,N‐embedded NGs (BN‐HNGs) bearing azepines was synthesized via stepwise regioselective cyclodehydrogenation. First, the phenyl‐ or nitrogen‐bridged dimers were efficiently clipped into highly congested model compounds 1 2 . Later, controllable Scholl reactions tetraphenyl‐tethered precursor generated 1, 7 8 new C−C bonds, thereby establishing robust method for preparation nonalternant BN‐HNGs with up to 31 fused rings. The bilayer nature unambiguously verified by X‐ray diffraction analysis. chirality transferred stereogenic boron centers upon fluoride coordination, concave‐concave structure comply skeleton. Notably, largest BN‐HNG ( 6 ) spontaneously resolved homochiral 4 helix as molecular spiral staircase during crystallization conglomerate formation at single‐crystal scale. large twisted C ‐symmetric π‐surface dynamic skeleton induced curved might have synergistic effects on self‐recognition enantiomers achieve intriguing spontaneous resolution behavior. chiroptical properties enantiomer further investigated, revealing that had strong response in visible range (400–700 nm).
Язык: Английский
Процитировано
2
Angewandte Chemie International Edition, Год журнала: 2024, Номер unknown
Опубликована: Июль 20, 2024
Abstract Introduction of non‐hexagons and/or heteroatoms allows for finely tuning the physicochemical properties nanographenes. Heteroatoms doping have dominated modulation nanographenes with tunable band gap, rich electrochemical activities and so on. The pair non‐hexagons, instance, pentagon‐heptagon pairs, furnished aromatic antiaromatic characteristics, open‐shell In order to meet growing demand versatile in materials science, research on novel heteroatom doped non‐hexagonal pairs has been aroused recent years. this review, we focus nitrogen‐doped paris including synthesis, structure analysis, photophysical properties, potential applications organic devices.
Язык: Английский
Процитировано
2
Angewandte Chemie International Edition, Год журнала: 2024, Номер unknown
Опубликована: Ноя. 18, 2024
The synthesis and stabilization of heteroatom-doped nanocarbon molecules, such as carbazole-containing (super)helicenes, present significant challenges due to the complexities involved in maintaining structural integrity electronic functionality. In this study, we successfully synthesized a carbazole-centered expanded tris-hexabenzo[7]helicene (1) via facile FeCl
Язык: Английский
Процитировано
1