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1.
Chemistry ; : e202402257, 2024 Jul 02.
Article in English | MEDLINE | ID: mdl-38955898

ABSTRACT

Boron-doped helicenes, known for their unique electronic and photophysical properties, are of great interest for numerous applications. This research introduces two new azabora[6]helicenes, H[6]BN1 and H[6]BN2, synthesized through an efficient method. These molecules have boron and nitrogen atoms in opposing positions, enhancing their distinctive attributes. Both helicenes show excellent emission properties, with H[6]BN1 and H[6]BN2 exhibiting narrowband blue fluorescence and circularly polarized luminescence (CPL), achieving glum values of 4~5 ×10-4 which is beneficial for chiroptical applications. The addition of a donor group, 3, 6-di-tert-butyl-9H-carbazole, in H[6]BN2 improves luminescence, likely due to enhanced molecular orbital overlap and electron delocalization. H[6]BN1's needle-like single crystals exhibit mechanochromism, changing luminescent color from yellow to green under mechanical stress, which is promising for stimulus-responsive materials. In conclusion, this study presents a novel class of BN[6]helicenes with superior chiroptical properties. Their combination of electronic features and mechanochromism makes them ideal for advanced chiroptical materials, expanding the potential of helicene-based compounds and offering new directions for the synthesis of molecules with specific chiroptical characteristics.

2.
Angew Chem Int Ed Engl ; 63(5): e202317294, 2024 Jan 25.
Article in English | MEDLINE | ID: mdl-38087842

ABSTRACT

A series of triarylboron-based graphdiyne analogues (TAB-GDYs) with tunable pore size were prepared through copper mediated coupling reaction. The elemental composition, chemical bond, morphology of TAB-GDYs were well characterized. The crystallinity was confirmed by selected area electron diffraction (SAED) and stacking modes were studied in combination with high resolution transmission electron microscope (HRTEM) and structure simulation. The absorption and desorption isotherm revealed relatively high specific surface area of these TAB-GDYs up to 788 m2 g-1 for TMTAB-GDY, which decreased as pore size enlarged. TAB-GDYs exhibit certain selectivity for CO2 /N2 (21.9), CO2 /CH4 (5.3), CO2 /H2 (41.8) and C2 H2 /CO2 (2.3). This work has developed a series of boron containing two-dimensional frameworks with clear structures and good stability, and their tunable pore sizes have laid the foundation for future applications in the gas separation field.

3.
Angew Chem Int Ed Engl ; 61(1): e202112290, 2022 Jan 03.
Article in English | MEDLINE | ID: mdl-34734465

ABSTRACT

Achieving full-color emission from a single chromophore is not only highly desirable from practical considerations, but also greatly challenging for fundamental research. Herein, we demonstrated the density-dependent emission colors from a single boron-containing chromophore, from which multi-color fluorescent polyurethanes were prepared as well. Originating from its switchable molecular conformations, the emission color of the chromophore was found to be governed by the packing density and strongly influenced by hydrogen bonding interactions. The chromophore was incorporated into polyurethanes to achieve full-color emitting materials; the emission color was only dependent on the chromophore density and could be tuned via synthetic approach by controlling the compositions. The emission colors could also be modulated by physical approaches, including by swelling/deswelling process, compression under high pressure, and even blending the fluorescent polyurethane with non-emitting ones.

4.
Chemistry ; 27(20): 6274-6282, 2021 Apr 07.
Article in English | MEDLINE | ID: mdl-33496983

ABSTRACT

A series of 9-borafluorene derivatives, functionalised with electron-donating groups, have been prepared. Some of these 9-borafluorene compounds exhibit strong yellowish emission in solution and in the solid state with relatively high quantum yields (up to 73.6 % for FMesB-Cz as a neat film). The results suggest that the highly twisted donor groups suppress charge transfer, but the intrinsic photophysical properties of the 9-borafluorene systems remain. The new compounds showed enhanced stability towards the atmosphere, and exhibited excellent thermal stability, revealing their potential for application in materials science. Organic light-emitting diode (OLED) devices were fabricated with two of the highly emissive compounds, and they exhibited strong yellow-greenish electroluminescence, with a maximum luminance intensity of >22 000 cd m-2 . These are the first two examples of 9-borafluorene derivatives being used as light-emitting materials in OLED devices, and they have enabled us to achieve a balance between maintaining their intrinsic properties while improving their stability.

5.
Luminescence ; 32(4): 652-660, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28493379

ABSTRACT

A diarylethene bearing a triazole-linked rhodamine B unit was synthesized. Its fluorescent emission was significantly enhanced in the presence of protons or Cu2+ due to transformation from the pirocyclic form to open-ring form. The fluorescence was quenched sequentially upon irradiation with 297 nm light based on the intramolecular fluorescence resonance energy transfer mechanism. In an acetonitrile: water binary solvent (1: 1 v/v), the compound showed significant fluorescent enhancement for Cu2+ compared with a wide range of tested metal ions with a fast response and a limit of detection of 2.86 × 10-8  mol L-1 . Using Cu2+ and UV light as the chemical inputs, and fluorescence intensity at 597 nm as the output, a logic gate was developed at the molecular level. Moreover, the compound can be used with a high accuracy to detect Cu2+ in a natural water sample.


Subject(s)
Copper/analysis , Fluorescent Dyes/chemistry , Rhodamines/chemistry , Acetonitriles/chemistry , Click Chemistry , Copper/metabolism , Fluorescent Dyes/chemical synthesis , Fluorescent Dyes/metabolism , Light , Limit of Detection , Magnetic Resonance Spectroscopy , Protons , Spectrometry, Fluorescence/methods , Trifluoroacetic Acid/chemistry , Water Pollutants, Chemical/analysis
6.
Spectrochim Acta A Mol Biomol Spectrosc ; 316: 124341, 2024 Aug 05.
Article in English | MEDLINE | ID: mdl-38676987

ABSTRACT

Hydrogen sulfide (H2S) is a common toxic gas that threatens the quality and safety of environmental water and food. Herein, a new near-infrared fluorescent probe DTCM was synthesized and characterized by single crystal X-ray diffraction for sensing H2S. It exhibited a remarkable "turn-on" near-infrared (NIR) emission response at 665 nm with a remarkably massive Stokes shift of 175 nm, super-rapid detection ability (within 30 s), excellent photostability, high selectivity and sensitivity (limit of detection, LOD = 58 nM). Additionally, the probe was successfully utilized for the detection of H2S in environmental water samples. The DTCM-loaded test papers enabled convenient and real-time monitoring of H2S produced by food spoilage.


Subject(s)
Fluorescent Dyes , Hydrogen Sulfide , Limit of Detection , Spectrometry, Fluorescence , Water , Hydrogen Sulfide/analysis , Fluorescent Dyes/chemistry , Fluorescent Dyes/chemical synthesis , Water/chemistry , Food Contamination/analysis , Spectroscopy, Near-Infrared/methods , Food Analysis/methods , Water Pollutants, Chemical/analysis
7.
Nat Chem ; 14(9): 1061-1067, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35798950

ABSTRACT

Single-molecule topological insulators are promising candidates as conducting wires over nanometre length scales. A key advantage is their ability to exhibit quasi-metallic transport, in contrast to conjugated molecular wires which typically exhibit a low conductance that decays as the wire length increases. Here, we study a family of oligophenylene-bridged bis(triarylamines) with tunable and stable mono- or di-radicaloid character. These wires can undergo one- and two-electron chemical oxidations to the corresponding mono-cation and di-cation, respectively. We show that the oxidized wires exhibit reversed conductance decay with increasing length, consistent with the expectation for Su-Schrieffer-Heeger-type one-dimensional topological insulators. The 2.6-nm-long di-cation reported here displays a conductance greater than 0.1G0, where G0 is the conductance quantum, a factor of 5,400 greater than the neutral form. The observed conductance-length relationship is similar between the mono-cation and di-cation series. Density functional theory calculations elucidate how the frontier orbitals and delocalization of radicals facilitate the observed non-classical quasi-metallic behaviour.

8.
Org Lett ; 23(15): 5836-5841, 2021 Aug 06.
Article in English | MEDLINE | ID: mdl-34251839

ABSTRACT

A series of dicyanomethylene-functionalized triarylboranes is reported in this work, with low-lying LUMO energy levels at ca. -3.66 eV for FMesB-ACN. The single-crystal structures of the mono- and dianion of Mes*B-ACN were obtained via chemical reduction, which revealed a conversion from a quinoidal to an aromatic structure. The strong Lewis acidity of these compounds is reflected in a fluoride-anion binding experiment. This work introduces a facile strategy for modulating the electron deficiency of boron-containing compounds.

9.
Chem Commun (Camb) ; 57(64): 7926-7929, 2021 Aug 10.
Article in English | MEDLINE | ID: mdl-34286739

ABSTRACT

A highly electron-deficient dicyanomethylene-bridged triarylborane, FMesB-TCN, was reported with a low-lying LUMO and crystallization-induced emission enhancement in its block-shape crystal. DFT calculations revealed lower re-organization energy of the block crystal than that of the weakly emissive acicular crystal. This work explored a novel boron-containing skeleton with interesting optical properties.

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