LIQUID CRYSTALS
·
2020
·
IF 2.908
Tianwen Fan,Rongxin Shi,Huaying Tang,Hongyu Guo,Fafu Yang
This paper reported not only the first fluorescein liquid crystals but also revealed the influence of peripheral alkyl chains on mesomorphic properties and photophysical properties. Novel fluorescein-triphenylene dimers 4a–4f with different alkyl chains were designed and synthesised in yields of 76–83%. Samples 4a, 4b, 4c and 4d with CH3 and C4H9 exhibited the columnar mesophase but samples 4e and 4f with C8H17 showed no mesophase. The longer alkyl chains on fluorescein units resulted in the lower phase transition temperature. The too long alkyl chain destroyed the liquid crystalline behaviour. Their fluorescence quantum yields were as high as 0.78–0.87 in CH2Cl2 solution and 0.11–0.17 in solid states. The longer alkyl chains leaded to the higher emission efficiencies.
研究领域:
材料化学
·
物理化学
✓ 已验证
DOI
高影响因子
LIQUID CRYSTALS
·
2018
·
IF 2.636
Huiyi Feng,Xiaotong Geng,Jianrong Lin,Hongyu Guo,Fafu Yang
The novel triphenylene-Bodipy derivatives 6 and 7 based on 1,3,5-triazine core were designed and synthesised by introducing BODIPY unit and triphenylene units sequentially onto cyanuric chloride. The Bodipy derivative 6 with one triphenylene unit was a nematic liquid crystal but the derivative 7 with two triphenylene units was a hexagonal columnar liquid crystal. The investigation on photophysical properties suggested that both of them exhibited excellent fluorescence with high fluorescence quantum yields and the Stokes shifts were larger than their Bodipy precursors. This research presented a good example of design and synthesis of columnar Bodipy liquid crystal with high fluorescence and large Stokes shift.
研究领域:
材料化学
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光学材料
·
有机合成
✓ 已验证
DOI
高影响因子
LIQUID CRYSTALS
·
2024
·
IF 2.4
Tao Deng,Hua Yan,Liangbin Lin,Hongyu Guo,Fafu Yang
Although some cyclotriveratrylene (CTV) liquid crystals had been reported, the CTV liquid crystal with high fluorescence in mesophase was not presented up to now. By introducing diphenylacrylonitrile units on CTV skeleton, two CTV derivatives with AIE units (7a and 7b) were prepared for the first time. Their structures and crown conformations were characterised by 1H NMR, 13C NMR, MALDI-MS spectra and elemental analysis. Samples 7a and 7b exhibited the reversible liquid crystalline behaviours with hexagonal columnar mesophase supported by the DSC, POM and XRD analysis. The studies on photophysical properties of samples 7a and 7b suggested the high fluorescence in solid state and mesophase. The absolute fluorescence quantum yield of 7b in mesophase was as high as 0.45. This work not only reported the first CTV liquid crystals with high fluorescence in aggregated state but also provided a good strategy for constructing the novel CTV liquid crystals with excellent fluorescence.
研究领域:
材料化学
·
光学材料
·
分子设计与合成
✓ 已验证
DOI
高影响因子
JOURNAL OF FLUORESCENCE
·
2024
·
IF 2.6
Li Maomao,Zhu Wenjie,Song Dongdong,Liang Zuoqin,Ye Changqing
Latent fingerprints (LFPs) is one of the most important physical evidence in the criminal scene, playing an important role in forensic investigations. Therefore, developing highly sensitive and convenient materials for the visualization of LFPs is of great significance. We designed and synthesized an organic fluorescent molecule TP-PH with aggregation-induced enhanced emission (AIEE) activity. By simply soaking, blue fluorescent images with high contrast and resolution are readily developed on various surfaces including tinfoil, steel, glass and plastic. Remarkably, LFPs can be visualized within 5 min including the first-, second- and tertiary-level details. In addition, TP-PH exhibits interesting photoactivated fluorescence enhancement properties. Under irradiation of 365 nm UV light with a power density of 382 mW/cm 2 , the fluorescence quantum yield displays approximately 21.5-fold enhancement. Mechanism studies reveals that the photoactivated fluorescence is attributed to the irreversible cyclodehydrogenation reactions under UV irradiation. This work provides a guideline for the design of multifunctional AIEE fluorescent materials.
研究领域:
材料科学
·
法医学
·
有机化学
✓ 已验证
DOI
PubMed
高影响因子
ACS Applied Nano Materials
·
2020
·
IF 0
Jun Wang,Qing Kuang,Xiaofang Su,Xiaowen Lu,Leipeng Leng,Mingyang Zhang,Chunmu Guo,Tong Li,Qian Xu,Shuhui Sun,J. Hugh Horton,Wei Wu,Zhijun Li
Supported single-atom catalysts have become one of the most exciting frontiers in heterogeneous catalysis. The physicochemical properties of these materials are highly interesting; however, the generation of stable single atoms on solid supports is still challenging. Herein, we report an efficient and operationally simple postsynthesis method, consisting of spatial confining, freeze-drying, and reducing steps, for the construction of singly dispersed palladium atoms on SAPO-31 (Pd1/SAPO-31) with promising application prospects in the semihydrogenation of alkynes. A typical Pd–N–C single-atom catalyst derived from the ZIF-8-supported palladium complex was prepared and compared to Pd1/SAPO-31. The Pd1/SAPO-31 catalyst showed outstanding performance in the semihydrogenation of both phenylacetylene (85% selectivity at 99% conversion, 40 min) and 1-chloro-4-ethynylbenzene (95% selectivity at 99% conversion, 60 min). In addition, this single-atom palladium catalyst was highly active in triethoxysilane oxidation. Most importantly, this catalyst retained its atomic dispersion and catalytic activity after high-temperature thermal treatment in Ar at 700 °C. This study demonstrates how zeolites can be used to confine atomically dispersed metal species and tune the activity and stability of these materials to meet the needs of practical applications.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2023
·Vol. 25
·期 17
·12342-12351
·
IF 3.3
Jie Peng,Xin He,Yao Li,Jianxin Guan,Baihua Wu,Xinmao Li,Zhihao Yu,Jian Liu,Junrong Zheng
Elucidating the mechanism of aggregation-induced emission (AIE) is a prerequisite for designing more AIE-gens. The diphenylethylene (DPE) featured molecules are one of the most important AIE-gens due to their propeller structure. Three representative DPE-featured AIE-gens, triphenylethylene, cis-stilbene, and trans-stilbene, are explored via ultrafast ultraviolet/infrared (UV/IR) spectroscopy and theoretical calculations. Both experimental and computational results suggest that readily crossing conical intersections (CIs) with flexible structural evolutions in solutions significantly reduces fluorescence, whereas crossing CIs is restricted because of high energy cost, and therefore no fast nonradiative decay can compete with spontaneous emission in solids. The mechanism also well explains the different emission quantum yields and interconversion ratios between cis-stilbene and trans-stilbene after photoexcitation.
研究领域:
光化学
·
理论计算
·
超快光谱学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Zhijun Li,Honghong Li,Dundong Yuan,Leipeng Leng,Mingyang Zhang,Minghui Di,J. Hugh Horton,Jun Wang,Litao Sun,Weiwei Sun
Exploring the interaction between metal and support is of great importance in enhancing the catalytic performance and deepening the mechanistic understanding of single atom catalysis. Here we describe a photoinduction method to construct atomically dispersed palladium atoms supported over defect-containing boehmite (γ-AlOOH) nanoleaf with a palladium loading of 0.32 wt%. The existence of singly dispersed palladium atoms is confirmed by spherical aberration correction electron microscopy, extended X-ray absorption fine structure measurement, and CO-absorbed diffuse reflectance infrared Fourier transform spectroscopy. This catalyst shows excellent catalytic efficiency in trans -stilbene epoxidation to yield trans -stilbene oxide (TOF: 416 h −1 ; conversion: 84 %; selectivity: 99 %), along with excellent recyclability and scalability. In addition, various aromatic olefins were successfully transformed into the corresponding epoxides with high selectivity and excellent yield. DFT study further reveals that the high catalytic activity originates from under-coordinated single palladium atoms in the defect-containing γ-AlOOH in a unique coordination environment. This lays the foundation for the facile creation of single atom catalysts and sheds light on the possibility for scale-up production.
研究领域:
催化化学
·
材料科学
·
理论化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）