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Synthesis and characterization of novel benzodithiophene-fused perylene diimide acceptors: Regulate photovoltaic performance via structural isomerism
摘要： Two isomeric benzodithiophene-fused perylene diimides, BPDI-1 and BPDI-2, are designed and synthesized via photo-induced ring-closure reaction between perylene diimide (PDI) acceptor and both isomeric benzodithiophene donor cores, including benzo[2,1-b:3,4-b']dithiophene (BDP) and benzo[1,2-b:4,3-b']dithiophene (BdT). The effect of structural isomerism on the molecular geometry, absorption, energy level, film morphology as well as photovoltaic performance is comparatively studied. It is found that the variation of the S atom substituted position in the donor cores results in distinct molecular geometries for the newly-developed BPDI-1 and BPDI-2 acceptors. Compared with BDP-containing BPDI-1, the incorporation of BdT core endows BPDI-2 with a remarkably enhanced backbone distortion. When blended with the commercially available polymer donor (PTB7-Th), such twisted structure feature for the BPDI-2 acceptor plays a key role in reducing molecule aggregation, which is helpful for the enhancements of short-circuit current density and photovoltaic efficiency effectively. As a result, non-fullerene solar cells fabricated from BPDI-2 acceptor achieve higher photovoltaic efficiency (4.44%) than that of BPDI-1 (2.98%), mainly benefited from superior short-circuit current density. This work provides us comparative understanding of isomeric geometry and device performance.
关键词： Benzodithiophene,Molecular geometry,Non-fullerene organic solar cells,Perylene diimide derivatives
更新于2025-11-19 16:56:42
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Two pH-responsive fluorescence probes based on indole derivatives
摘要： Two new pH ?uorescent probes 2,8-bis((E)-2-(1,1-dimethyl-1H-benzo[e]indol-2-yl)vinyl)-6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine (1) and 2,8-bis((E)-2-(3,3-dimethyl-3H-indol-2-yl)vinyl)-6H,12H-5,11-methanodibenzo[b,f] [1,5]diazocine (2) were designed and synthesized via ethylene bridging of the Tr?ger's Base (TB) framework and indole derivatives. As the protonation of nitrogen atoms of indole derivatives, both probes displayed the signi?cant pH-dependent spectral properties. The probing behavior toward pH variations indicated that probes exhibited excellent pH dependent behavior in the pH ranges of 2.07–7.01 (1) and 1.96–7.01 (2), especially possessing good linear response in the pH ranges of 2.50–4.00. The emissions of 1 can be reversibly switched between brilliant yellow and dark states by protonation and deprotonation. Also, the yellow-green ?uorescence emission of 2 could be quenched upon protonation. Such behaviors enable them to work as turn-o? ?uorescent pH sensors in the solution state. Furthermore, protonation and deprotonation on indole moiety nitrogen of the probe 1 and 2 provided a sensing mechanism for pH changes. In addition, both probes performed good photostability, high selectivity and excellent reversibility.
关键词： Sensors,Fluorescent probe,pH detection,Luminescence,Indole derivatives
更新于2025-11-19 16:56:35
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A mitochondria-targeted ratiometric fluorescent probe for detection of SO2 derivatives in living cells and in vivo
摘要： A new near-infrared (NIR) ?uorescent probe for colorimetric and ratiometric detection of SO2 derivatives was developed based on conjugated hybrid coumarin-hemicyanine. The probe can detect HSO3?/SO32? in HEPES bu?er (10 mM, pH 7.4, with 10% DMF, v/v) with a large emission shift (259 nm). Importantly, it was successfully used for ?uorescence imaging of endogenous bisul?te in BT-474 cells and zebra?sh.
关键词： Near-infrared ?uorescent probe,SO2 derivatives,Mitochondria-targeted,Ratiometric,Colorimetric
更新于2025-11-19 16:56:35
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Tunable Photophysical Properties of Thiophene Based Chromophores: Conjoined Experimental and Theoretical Investigation
摘要： In this paper we report synthesis and photophysical properties of six novel thiophene derivatives (ThD) with D-π-A structure. The subject of this work are three nitrophenyls (1) BT-Th-NO2 and three benzonitriles (2) BT-Th-CN, substituted at different positions of aromatic ring ((a) ortho-, (b) meta- or (c) para-). Dyes were obtained using simple three-step synthesis and their chemical structures were confirmed by 1H and 13C NMR, IR as well as high resolution mass spectrometry. The influence of positional isomerism on optical properties has been explored experimentally and theoretically. The photophysical properties were investigated using steady-state as well as time-resolved spectroscopy and the obtained results were supported by quantum-chemical calculations. TD-DFT calculations indicated that charge-transfer strength can be correlated with the observed optical properties. In addition, the influence of the acceptor position on photoluminescence spectra, fluorescence quantum yields and emission lifetimes was specified. We show that ThD optical properties can be tuned in wide spectral range by the change made in only single step of synthesis reaction.
关键词： push-pull chromophores,Thiophene derivatives,TD-DFT,quantum yield,charge transfer
更新于2025-11-19 16:46:39
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Spectroscopic and Theoretical Studies of Dual Fluorescence in 2-Hydroxy-N-(2-phenylethyl)benzamide Induced by ESIPT Process – Solvent Effects
摘要： This work discusses the theoretical ([TD]DFT) and spectroscopic investigation into 2-Hydroxy-N-(2-phenylethyl)benzamide (SAL3) and its physiochemical behaviour in the selected organic solvents. The compound demonstrated a dual fluorescence effect in alcoholic solutions (methanol, ethanol, isopropanol), while in acetonitrile (ACN), dimethylsulfoxide (DMSO) and non-polar solvents (n-Hexane, n-Heptane, chloroform) only a single emission maximum was observed. The noticeable shortening of average fluorescence lifetime, the employed detailed analysis of solvatochromic shifts of absorption spectra in the function of polarizability related to a change in the induction polarization of the environment and, above all, the performed quantum-mechanical calculations [TD] DFT with a detailed analysis of excited states, clearly indicate a connection between the observed fluorescence effects and processes related to changes in the system’s structure in the excited state. Based on these experimental and theoretical studies, it has been proposed that the environment (solvent) polarity-induced dual fluorescence effect in SAL3 is related to the Excited-State Intramolecular Proton Transfer (ESIPT) process. Also, the quantum-mechanic studies [TD] DFT point to the specific conformation of SAL3 molecule characteristic of dual fluorescence emission.
关键词： dual fluorescence effect,salicylic acid derivatives,[TD] DFT calculations,molecular spectroscopy,H-bonds
更新于2025-09-23 15:23:52
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Nitrogen-embedded small-molecule semiconducting materials: Effect of chlorine atoms on their electrochemical, self-assembly, and carrier transport properties
摘要： We reported three novel nitrogen-embedded small molecules 4a, 4b, and 4c, which were synthesized from the condensation reactions of benzo[1,2-b:4,5-b']difuran-2,6(3H,7H)-dione with 1-(2-ethylhexyl)-1H-pyrrolo[2,3-b]pyridine-2,3-dione, 6-chloro-1-(2-ethylhexyl)-1H-pyrrolo[2,3-b]pyridine-2,3-dione, or 4,6-dichloro-1-(2-ethylhexyl)-1H-pyrrolo[2,3-b]pyridine-2,3-dione, respectively. Their optical, electrochemical properties, self-assembly behavior, and carrier transport properties were studied by a range of experimental and theoretical methods, and the effect of chlorine atoms were well discussed. Energy levels of the highest occupied molecular orbitals and the lowest unoccupied ones for these molecular materials locate at ?5.92～?6.02 and ?4.25～?4.37 eV, respectively. Bottom gate/bottom contact field-effect transistors based on 4a, 4b, and 4c exhibited n-channel transport characteristics with the highest electron mobility of 7.57 × 10?3 cm2 V?1 s?1. Thin film microstructure investigations revealed 4a and 4c perform lamellar molecular packing with random orientations to the OTS-treated SiO2 substrate, while 4b conducts a highly crystalline, edge-on, lamellar packing though large grain boundaries exist in its thin film.
关键词： Isoindigo derivatives,Chlorine atoms,Small-molecule semiconductors,Electron mobilities,Organic field-effect transistors
更新于2025-09-23 15:23:52
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A Complete Active Space Self-Consistent Field and Density Functional Theory Study of S0, T1, S1 States of Five Phenol ortho-Derivatives
摘要： The low-lying electronic states (S0, S1 and T1) of five phenol ortho-derivatives have been studied by the complete active space self-consistent field (CASSCF) and B3LYP methods. Structure optimizations indicate that the S1 structures of 2-nitrophenol, salicylaldehyde, 2-acetylphenol are H transfer structures, but those of salicylamide and salicylic acid not. The T1 structures are all H transfer structures. To these five phenol ortho-derivatives, all the transitions of S0→S1 and S0→T1 are come from the HOMO to LUMO orbital, and show π-π* transition characters. Additionally, ortho-effect is also discussed.
关键词： Phenol o-derivatives,Complete active space self-consistent field,Density functional theory
更新于2025-09-23 15:23:52
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Metal-Organic Frameworks as Hosts for Fluorinated Azobenzenes: A Path Towards Quantitative Photoswitching with Visible Light
摘要： Fifteen new photochromic hybrid materials were synthesized by gas phase loading of fluorinated azobenzenes, namely ortho-tetrafluoroazobenzene (tF-AZB), 4H,4H'-octafluoroazobenzene (oF-AZB), and perfluoroazobenzene (pF-AZB), into the pores of the well-known metal-organic frameworks MOF-5, MIL-53(Al), MIL-53(Ga), MIL-68(Ga), and MIL-68(In). Their composition was analysed by elemental (CHNS) and DSC/TGA analysis. For pF-AZB0.34@MIL-53(Al) a structural model based on high-resolution synchrotron powder diffraction data was developed and the host-guest and guest-guest interactions were elucidated from this model. These interactions of O-H…F and π…π type were confirmed by significant shifts of the O-H frequencies in loaded and unloaded MOFs of the MIL-53 and MIL-68 series. Most remarkably, all of the synthesized F-AZB@MOF systems can be switched with visible light and some of them show almost quantitative (> 95 %) photo-isomerization between its E and Z forms with no significant fatigue after repeated switching cycles.
关键词： azobenzene,fluorinated derivatives,solid state switching,metal-organic frameworks,photochromism
更新于2025-09-23 15:23:52
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New Coumarin-benzoxazole derivatives: Synthesis, photophysical and NLO properties
摘要： In this work, a series of novel D-π-A structure coumarin-benzoxazole derivatives have been synthesized. The third-order NLO properties of the coumarin derivatives in DMSO are investigated by Z-scan measurement, and the photophysical properties of the compounds are studied through experimental and theoretical calculation methods. The results showed that the introducing specific functional groups at multiple active sites of coumarin reduced the π-π intermolecular stacking, while the formation of push-pull structure decreased E-gap of entire molecule. The excellent third-order NLO responses based on chromophore 4c with maximum nonlinear absorptive coefficients is 50.64 × 10-13 esu and the largest second-order NLO hyperpolarizability is 7.12 × 10-30 esu. Experimental results have also been confirmed through DFT, TDDFT and ZINDO calculations. Our results indicate that the coumarin fluorescent dyes are promising candidate materials for NLO applications.
关键词： ZINDO calculation,DFT,Fluorescent,Third-order nonlinear,Coumarin derivatives
更新于2025-09-23 15:23:52
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Synthesis, characterization and photophysical properties of meso-indole-boron-dipyrromethene derivatives and their cell imaging and viscosity sensing
摘要： Based on the molecular design and structural modification of boron-dipyrromethene (BODIPY), two new BODIPY derivatives with meso-substituted functional indole moieties were successfully prepared. These new compounds were characterized by NMR, HRMS and FTIR, exhibiting the different UV-vis and PL spectral phenomena because of their varied molecular structures in various solvents and different degrees of negative solvatochromism. Theoretical calculations and CV results show that the substituted NO2 group at 5-position of indole is favorable for increasing the oxidation potential of the molecules, while the NH2 group is the opposite. These two BODIPY derivatives have different sensitivities to pH changes, and can be appropriately applied as cell imaging materials due to their good physical chemical characteristics and excellent biocompatibility. In particular, the fluorescence characteristics of BODIPY derivative with the substituted NH2 group at 5-position of indole show a good solvent viscosity dependence, highlighting its potential application for testing the intracellular viscosity changes of the living cell in disease diagnosis.
关键词： meso-indole boron-dipyrromethene derivatives,photoluminescence,fluorescence characteristics,cell imaging,viscosity sensing
更新于2025-09-23 15:23:52