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A fluorescent probe based on tetrahydro[5]helicene derivative with large Stokes shift for rapid and highly selective recognition of hydrogen sulfide
摘要： In this work, we have designed and synthesized a dinitrobenzene-sulfonate tetrahydro[5]helicene (H-DNP) as an effective fluorescent probe for detection of hydrogen sulfide (H2S). Upon the addition of H2S, a significant fluorescence enhancement (75-fold) at 495 nm can be observed with a distinct color change from colorless to yellow. Additionally, H-DNP shows low background spectroscopic signal, large Stokes Shift up to ~140 nm, good sensitivity, rapid response time less than 2 min, low detection limit (48 nM) and high selectivity towards common bio-thiols (Cysteine, Homocysteine and Glutathione). Compared with the previous dinitrophenoxy tetrahydro[5]helicene, this probe has shorter response time and lower detection limit. Most importantly, this probe H-DNP has low toxicity to cells and excellent cell permeability, which can be applied to visualize H2S in living cells.
关键词： Fluorescence,Cell imaging,Probe,4-dinitrobenzene,Helicene,2,Hydrogen sulfide
更新于2025-11-21 11:08:12
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D-??-D molecular semiconductors for perovskite solar cells: the superior role of helical versus planar ??-linker
摘要： Controlling the mode of molecular packing and the size of molecular aggregate are of fundamental importance for high-performance charge transporting materials in next-generation optoelectronic devices. To clarify the peculiar role of helicene as kernal blocks in the exploration of unconventional organic semiconductors, in this work thia[5]helicene (T5H) is duplicately aminated with electron-donating dimethoxydiphenylamine to afford T5H-OMeDPA, which is systematically compared with its perylothiophene (PET) congener (PET-OMeDPA). On the basis of quantum theory of atoms in molecules and energy decomposition analysis of single-crystals, it is suprisingly found that while π-π stacking of planar PET is stronger than that of helical T5H, this desirable effect for charge transport of organic semiconductors is completely lost for donor-π-donor (D-π-D) typed PET-OMeDPA, but is retained for T5H-OMeDPA to a large extent. Consequently, T5H-OMeDPA single-crystal presents an about 5 times higher theoretical hole-mobility than PET-OMeDPA. More critically, the solution-processed racemic glassy film of T5H-OMeDPA displays a 3 times higher hole-mobility in comparison with the PET-OMeDPA counterpart, due to a larger domain of molecular aggregate. With respect to PET-OMeDPA, there is a weaker electronic coupling of helical T5H-OMeDPA with perovskite, leading to a reduced interfacial charge recombination. Due to reduced transport resistance and enhanced recombination resistance, perovskite solar cells with T5H-OMeDPA exhibit a power conversion efficiency of 21.1%, higher than that of 19.8% with PET-OMeDPA and that of 20.6% with spiro-OMeTAD control.
关键词： charge transport,perovskite solar cells,helicene,molecular semiconductors,π-π stacking
更新于2025-09-23 15:21:01
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Sequential selfa??catalytic reactions in the formation of heteroa??doublea??helix and their selfa??assembled gels by pseudoenantiomer mixtures of ethynylhelicene oligomers
摘要： A 1:1 mixture of pseudoenantiomer ethynylhelicene (P)-pentamer and (M)-tetramer in toluene formed hetero-double-helix and their self-assembled gels. Kinetic analysis under isothermal conditions showed a complex nonlinear nature with regard to temperature changes. At 60°C, sigmoidal kinetics were observed, which disappeared after seeding with the self-assembled gels. These findings indicate the involvement of self-catalytic reaction I, in which a hetero-double-helix catalyzes the reaction to form a hetero-double-helix from random-coils. At 20°C, stairwise biphasic kinetics were observed, which disappeared after seeding. This phenomenon was explained by the involvement of two reactions with sigmoidal kinetics, namely, the formation of self-assembled gel I from hetero-double-helix by self-catalytic reaction II and the formation of self-assembled gel II by self-catalytic reaction III. Constant-rate temperature change experiments between 90 and 5°C showed nonsigmoidal thermal hysteresis in accordance with the involvement of sequential self-catalytic reactions with different reaction rates.
关键词： stairwise biphasic kinetics,helicene oligomer,self-assembly,hetero-double-helix,sequential self-catalytic reactions
更新于2025-09-23 15:19:57