16 results on '"Lu, Ran"'
Search Results
2. Studying of photoluminescence property of carbazole unit based push-pull oligomers.
- Author
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Chen, Ying, Lu, Ran, Sui, Ning, Zhang, Ye, Wang, Wenyan, Kang, Zhi-hui, Wang, Ying-hui, and Zhang, Han-zhuang
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CARBAZOLE , *INTRAMOLECULAR charge transfer , *LIGHT emitting diodes , *PHOTOLUMINESCENCE , *REDSHIFT , *EXCITED states - Abstract
The photoluminescence (PL) property of two push-pull oligomers named C2B and DC2B, comprising of carbazole and difluoroboron β-diketonate units, were probed by many optical tests. A comparison of the PL property of C2B and DC2B indicated that the introduction of carbazole unit red shifted the spectral feature and accelerated PL relaxation rate. Meanwhile, it also accelerated the rate of intramolecular charge transfer (ICT), the reorganization of excited state and relaxation from the ICT state to the ground state, based on the global analysis of transient absorption data. Finally, C2B and DC2B were mixed together and engineered into white light emitting diode test, showing a correlated color temperatures (CCT) value of 4687 K, indicating their potential in the organic displaying devices. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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3. Luminescent Organogels Generated from Nucleosides Functionalized with Carbazole: Synthesis and Probing for F-.
- Author
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Jia, Xiaoyu, Zhao, Jinyu, Xu, Shenzheng, Zhang, Fushuang, Sun, Jingbo, and Lu, Ran
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NUCLEOSIDES ,NUCLEOSIDE synthesis ,GELATION ,CARBAZOLE ,CHEMICAL synthesis ,LUMINESCENCE - Abstract
Novel luminescent organogelators based on nucleoside functionalized with carbazole (UC8, UC12 and UC16) were designed and synthesized. Their gelation ability was tested and it was found that both UC12 and UC16 could form stable organogels in toluene/petroleum ether. The UV-vis absorption, fluorescence emission and IR spectral changes during the gelation of UC12 proved that the self-assembly was driven by H- bonding. The morphology of the xerogel UC16 obtained from toluene/petroleum ether (v/v = 1/1) displayed tough rod-like microstructures, and 3D networks formed from lots of nanofibers were observed for the xerogel UC16 obtained from toluene/petroleum ether (v/v = 2/1). It was interesting that the obtained organogels emitting blue light could be destroyed by the addition of F-, accompanied with the declining the emission intensity. Therefore, these organogels could be used as sensory materials to recognize F-. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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4. Role of tert-butyl in the linear and nonlinear optical property of push-pull chromophores.
- Author
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Chi, Xiao-Chun, Lu, Ran, Yu, Gao, Wang, Ying-Hui, Zhou, Shang-Hang, Sui, Ning, Wang, Wen-Yan, Ni, Mou-Cui, Yang, Yan-Qiang, and Zhang, Han-Zhuang
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BUTYL group , *CHROMOPHORES , *NONLINEAR optics , *BORON , *CARBAZOLE - Abstract
Through comparing the linear and nonlinear optical property of two pull-push chromophores, which are composed of difluoroboron β-diketonate functionalized with carbazole and tert-butyl carbazole, the role of tert-butyl in chromosphere has been discussed in detail. The tert-butyl unit would lead to the absorption and fluorescence peak red shift and accelerate the fluorescence relaxation rate of chromophores. Moreover, the tert-butyl unit would affect obviously the two-photon optical property of chromophore according to the Z-scan test. The transient absorption (TA) data shows that these two pull-push chromopphores both own intramolecular charge transfer (ICT) characteristics and the tert-butyl unit accelerate the dynamic rate of ICT generation and relaxation process, which may be responsible for the variance of fluorescence property. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
5. Mechanofluorochromism of D-π-A-Type Difluoroboron β-Carbonyl Cyclic Ketonate Complexes that Contain a Carbazole Unit.
- Author
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Zhang, Fushuang, Liu, QingwEN, ChEN, Yuannan, Zhai, Lu, Liu, Mingyang, Sun, Jingbo, Mi, WENhua, Sun, MENg, and Lu, Ran
- Subjects
CARBAZOLE ,BUTYL group ,MOLECULAR emission cavity analysis - Abstract
Four new D-π-A-type difluoroboron β-carbonyl cyclic ketonate complexes that contain carbazole units ( TCCH, TCCP, CCH, and CCP) have been synthesized that exhibited reversible mechanofluorochromic (MFC) behaviors. Interestingly, TCCH and TCCP, which contained a tert-butyl carbazole group, exhibited high-contrast mechanofluorochromism compared with CCH and CCP, which just contained a carbazole group. For example, shifts of Δ δ=49 and 20 nm were detected during the mechanofluorochromism of TCCH and CCH, respectively. We found that tert-butyl carbazole derivatives existed as isolated molecules in the as-synthesized crystals, on account of the steric hindrance of the tert-butyl groups, and that J-aggregates were formed upon grinding. Transformation between the isolated and aggregated molecules, which was stimulated by mechanical force, led to clear changes in the emission properties. However, J-aggregates were formed in the as-synthesized crystals of carbazole derivatives, and grinding only weakened the strength of the π-π interactions, thereby resulting in low-contrast mechanofluorochromism. Therefore, this approach provides a useful strategy for the design of MFC dyes with high performance. [ABSTRACT FROM AUTHOR]
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- 2017
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6. Luminescence switching of a persistent room-temperature phosphorescent pure organic molecule in response to external stimuli.
- Author
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Xue, Pengchong, Sun, Jiabao, Chen, Peng, Wang, Panpan, Yao, Boqi, Gong, Peng, Zhang, Zhenqi, and Lu, Ran
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CARBAZOLE ,CHEMICAL synthesis ,ALDEHYDES ,BENZENE ,LUMINESCENCE ,MECHANICS (Physics) - Abstract
4-(Carbazol-9-yl)benzaldehyde could emit yellow RTP, which could last for 3 s because of efficient intersystem crossing. Moreover, multicolor luminescent switches could be realized by simply applying a mechanical force stimulus. [ABSTRACT FROM AUTHOR]
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- 2015
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7. Linear Oligocarbazole-Based Organogelators: Synthesis and Fluorescent Probing of Explosives.
- Author
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Hong, Guanghui, Qian, Chong, Xue, Pengchong, Liu, Xingliang, Wang, Qingqing, Liu, Mingyang, Gong, Peng, and Lu, Ran
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CARBAZOLE ,AMINES ,NANOFIBERS ,ULTRAVIOLET radiation ,TOLUENE - Abstract
The simplest carbazole-based organogelator C1 (9-hexadecyl-9 H-carbazole) has been synthesized and can self-assemble into nanofibers in the gel phase directed by balanced π-π interactions. To extend the conjugation of the π gelator, we prepared linear carbazole-based trimer C3 and pentamer C5, which also exhibited gelation behavior in some organic solvents upon ultrasound stimulation. It is found that the xerogel of C3 emits strong blue light under UV irradiation. Notably, the emission of C3 in nanofiber-based films can be quenched upon exposure to vapors of TNT and DNT. The steady-state Stern-Volmer plots of C3 in toluene revealed that the fluorescent quenching induced by aromatic nitro compounds is due to photoinduced electron transfer. Therefore the emitting nanofibers fabricated from linear carbazole by organogelation can be used as fluorescent sensors to detect explosives. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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8. High-contrast mechanofluorochromism and acidochromism of D-π-A type quinoline derivatives.
- Author
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Shen, Yanbing, Xue, Pengchong, Liu, Jiaxi, Ding, Jipeng, Sun, Jingbo, and Lu, Ran
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QUINOLINE derivatives , *TRIPHENYLAMINE , *CARBAZOLE , *FLUORESCENCE , *BLUE light - Abstract
Abstract New D-π-A type quinoline derivatives (CbzVQ and TPAVQ) were synthesized via Knoevenagel condensation reactions. They exhibited reversible high-contrast mechanofluorochromic (MFC) behavior under grinding/fuming treatment. Taking CbzVQ as an example, its fluorescence could be switched from blue to greyish green by grinding the as-synthesized sample into ground powders, and the fluorescence emission was red-shifted from 449 nm (with shoulders at 475 nm and 520 nm) to 578 nm (with shoulders at ca. 450 nm and 500 nm). Such large shift of the maximal emission peak during MFC processes was rare reported. In addition, the casting films of CbzVQ and TPAVQ emitted blue and green light, respectively, which was turned to red rapidly induced by TFA (trifluoroacetic acid) vapor. Moreover, the emission could be recovered stimulated by TEA (triethylamine) vapor, so the quinoline derivatives exhibited reversible fluorescent sensory properties. TPAVQ showed better performance in the detection of TFA vapor than CbzVQ due to the strong electron-donating ability of triphenylamine compared with carbazole. The detection limit and the decay time of TPAVQ towards TFA vapor were 163 ppb and 0.22 s, respectively. Apparently, the D-π-A type quinoline derivatives are candidates as multi-stimuli responsive fluorescent materials. Graphical abstract Image 1 Highlights • New D-π-A type quinoline derivatives bearing carbazole and triphenylamine are synthesized. • Quinoline derivatives show reversible high-contrast mechanofluorochromism. • The shift of the maximal emission for CbzVQ reaches 129 nm during mechanofluorochromic processes. • The emitting color of quinoline derivatives is turn to red from blue or green rapidly stimulated by TFA vapor. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
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9. Switching in visible-light emission of carbazole-modified pyrazole derivatives induced by mechanical forces and solution-organogel transition.
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Sun, Meng, Zhai, Lu, Sun, Jingbo, Zhang, Fushuang, Mi, Wenhua, Ding, Jipeng, and Lu, Ran
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PYRAZOLES , *VISIBLE spectra , *FLUORESCENCE , *ORGANIC solvents , *NONAQUEOUS solvents - Abstract
Abstract New carbazole-modified pyrazole derivatives were synthesized. It was found that tert -butylcarbazole derivatives of TCPDP , TCPHP , TCPPM and TCPPF exhibited reversible mechanofluorochromic (MFC) behavior under the treatment of grinding/fuming with CH 2 Cl 2. Particularly, the emission of the as-synthesized crystals of TCPDP was weak and emerged in the ultraviolet region, while the grinding led to significant red-shift of the emission to the visible-light region, accompanied with the significant fluorescence enhancement on account of the formation of J -aggregates. Thus, TCPDP showed intriguing fluorescence switching in visible-light region during MFC processes, which could be easily observed visually. Additionally, TCPDP , TCPHP , TCPPM and TCPPF could form stable organogels in some organic solvents. Notably, the solutions of TCPPM and TCPPF were almost non-emissive, but gelation-induced blue emission was achieved. Thus, the fluorescence could be also turned on due to the AIE (aggregation-induced emission) during the gel formation. Graphical abstract Image 1 Highlights • New carbazole-modified pyrazole derivatives were synthesized. • Tert -butylcarbazole derivatives showed reversible mechanofluorochromism and good gelation abilities. • High-contrast mechanofluorochromism of TCPDP was achieved via fluorescence switching in visible-light region. • Gelation-induced emission of TCPPM and TCPPF was detected. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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10. Mechanofluorochromism of NIR-emitting dyes based on difluoroboron β-carbonyl cyclic ketonate complexes.
- Author
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Zhang, Fushuang, Zhai, Lu, Feng, Siwei, Mi, Wenhua, Sun, Jingbo, Sun, Meng, Zhao, Jinyu, and Lu, Ran
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NEAR infrared spectroscopy , *INFRARED spectroscopy , *SOLID state chemistry , *LUMINESCENCE , *PHOTON emission - Abstract
New difluoroboron β-carbonyl cyclic ketonate complexes CnB (n = 2, 16), in which carbazole was linked to difluoroboron β-diketonate directly, and DCnB (n = 2, 16), where two terminal carbazole units were bridged by vinyl groups to link to difluoroboron β-diketonate core, were synthesized. They exhibited reversible mechanofluorochromic (MFC) behavior under grinding/fuming or heating treatment. Particularly, the emission of DC2B and DC16B emerged in the range of 650–850 nm in the solid-state. They gave red and rose-red luminescence in the as-synthesized crystals and in the ground powders, respectively, during MFC processes. Such MFC materials emitting NIR (near-infrared) light were seldom reported. In addition, compared with C2B , C16B showed high-contrast mechanofluorochromism because the long alkyl chain might decrease the strength of π-π interactions in the as-synthesized crystals, leading to the emission appeared at the high-energy region (483 nm). The disassembling of parts of π-aggregates and the improvement of the molecular planarity led to red-shift of the emission (509 nm) upon grinding. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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11. Self-assembling and photophysical properties of the organogelators based on cyanostyryl-substituted carbazoles.
- Author
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Simalou, Oudjaniyobi, Boyode, Pakoupati, Kpegba, Kafui, Xue, Pengchong, Lu, Ran, and Zhang, Tierui
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CARBAZOLE derivatives , *CARBAZOLE , *MOLECULAR self-assembly , *SCANNING electron microscopy , *GELATION - Abstract
Four cyanostyryl-substituted carbazole derivatives (CN-ODEC1, CN-ODEC2, CN-DDEC1, and CN-DDEC) were synthesized and their self-assembly properties have been studied. It was found that they could form organogels especially in aromatic solvents. Scanning electron microscopy and light microscopy images show that the xerogels formed from monosubstituted derivatives (CN-O/DDEC1) gave well-organized tapes, and those from disubstituted derivatives (CN-O/DDEC2) exhibited heavy entangled three-dimensional structures. The UV–vis absorption and fluorescence emission spectra, as well as X-ray diffraction patterns, suggest that carbazole derivatives underwent J-type π-stacking. Meanwhile, we suggested that strong H-bonding and moderate π–π interactions were the key driving force for the gelation of the monosubstituted derivatives, and head-to-tail “ladder-type” J-aggregates were formed in the gel state. On the other hand, strong π–π interaction might be considered as the main driving force for the gelation of disubstituted derivatives, and J-aggregates with no well-organized packing mode of molecules were obtained in the gel phase. It should be noticed that aggregation-induced emission was observed during the gelation processes. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
12. Multi-color solid-state luminescence of difluoroboron β-diketonate complexes bearing carbazole with mechanofluorochromism and thermofluorochromism.
- Author
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Liu, Mingyang, Zhai, Lu, Sun, Jingbo, Xue, Pengchong, Gong, Peng, Zhang, Zhenqi, Sun, Jiabao, and Lu, Ran
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BORON compounds , *CARBAZOLE , *LUMINESCENCE , *THERMOCHROMISM , *FLUORESCENCE yield , *SOLID state chemistry , *COMPLEX compounds - Abstract
New difluoroboron β-diketonate complexes functionalized with tert -butyl carbazole and carbazole ( TCBM and CBM ) have been synthesized, and they give strong emission in solid states with the fluorescence quantum yields of 0.63 and 0.99, respectively. Reversible mechanofluorochromic behaviors of TCBM and CBM are realized upon the treatment of grinding/fuming with CH 2 Cl 2 . Interestingly, the emitting colors of the annealed samples gained from the ground powders of TCBM depend on the heating temperature, and change from orange to yellow, yellowish green, and green with increasing temperature. The X-ray diffraction patterns illustrate that the transformation processes from crystalline structure to partial destroyed crystalline structure, till to amorphous state lead to the multi-color solid-state luminescence during thermofluorochromism. We deduced that tert -butyl can lead to the incompact packing of luminophores, which is more sensitive to external stimuli, so that multi-color solid-state luminescence can be afforded during mechanofluorochromic and thermofluorochromic processes. [ABSTRACT FROM AUTHOR]
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- 2016
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13. Synthesis of π-extended N-fused heteroacenes via regioselective Cadogan reaction.
- Author
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Gong, Peng, Li, Leijiao, Sun, Jingbo, Xue, Pengchong, and Lu, Ran
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ACENES , *CHEMICAL reactions , *CARBAZOLE , *SUBSTITUTION reactions , *CHEMICAL synthesis - Abstract
New indolocarbazole derivatives have been synthesized via Cadogan reaction. It has been found that the reductive cyclization of 3-(2-nitrophenyl)carbazoles prefers to take place on 4-position instead of 2-position in carbazole rings. Because electrophilic substitution was one of the main steps in Cadogan reaction and the Fukui function analysis for 9-methyl-3-(2-nitrophenyl)-9 H -carbazole revealed that more positive part of f − ( r ) function was localized at 4-position than at 2-position in carbazole, the 4-position was the favorite reactive site for the reductive cyclization. Such regioselective Cadogan reaction would be useful for the synthesis of π-extended N -fused heteroacenes with desired functionalities. [ABSTRACT FROM AUTHOR]
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- 2016
- Full Text
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14. Luminescent nanofibers fabricated from triphenylvinyl substituted carbazole derivatives via organogelation for sensing gaseous nitroaromatics.
- Author
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Gong, Peng, Sun, Jingbo, Xue, Pengchong, Qian, Chong, Zhang, Zhenqi, Sun, Jiabao, and Lu, Ran
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LUMINESCENCE , *PHENYL compounds , *CARBAZOLE derivatives , *SUBSTITUTION reactions , *GELATION , *NITROAROMATIC compounds - Abstract
New triphenylvinyl substituted carbazole derivatives TPEICE , TPEC and TPECBr have been synthesized. They could self-assemble into nanofibers via organogelation processes in some organic solvents. Notably, the obtained xerogel-based films could emit strong fluorescence although the three compounds were non-emissive in solutions, indicating AIE in gel phases. The emission of TPEICE and TPEC in xerogel-based films could be quenched significantly upon exposed to gaseous DNT and TNT, while TPECBr could not sense nitro compounds on account of its poor electron donating ability. We also found that reversibility of the fluorescence response of TPEC was better than TPEICE because the photo-induced electron transfer would happen during the recognition of nitroaromatics for TPEICE and TPEC , except for the formation of charge–transfer complex between TPEICE and nitro compounds. Therefore, the different fluorescence response behaviors of TPEICE , TPEC and TPECBr towards nitroaromatics were resulted from their different electron donating abilities. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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15. Branched benzothiadiazole-cored oligomers with terminal carbazoles: Synthesis and fluorescence probing nitroaromatics.
- Author
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Peng, Jiang, Ye, Kaiqi, Sun, Jingbo, Zhan, Yong, Jia, Junhui, Xue, Pengchong, Zhang, Gonghe, Zhang, Zhenqi, and Lu, Ran
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THIADIAZOLES , *NITROAROMATIC compounds , *OLIGOMERS , *CARBAZOLE , *FLUORESCENT probes , *CHEMICAL synthesis , *PHOTOINDUCED electron transfer - Abstract
New branched benzothiadiazole-cored conjugated oligomers with terminal carbazoles 1 and 2 have been synthesized. It was found that no obvious shifts of the maximal absorption bands for 1 and 2 were detected in the films compared with those in solutions, indicating weak π-π stacking occurred in the solid states on account of site isolation effect of the branched architectures. Hence, the synthesized oligomers could emit strong red light in the films. Notably, the emission of the films based on 1 and 2 could be quenched obviously upon exposed to gaseous TNT and DNT. The fluorescence quenching efficiency of the oligomer 2 -based film reached 91% when exposed to the saturated vapor of DNT for 3 min at 55 °C. The linear Stern–Volmer plot and the decrease of the fluorescence lifetime of 2 induced by DNT suggested the fluorescence sensing mechanism was due to the photo-induced electron transfer. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
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16. Synthesis, photophysical and electroluminescent properties of phenanthroimidazole derivatives with terminal carbazole or pyrene.
- Author
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Peng, Jiang, Ye, Kaiqi, Zhang, Gonghe, Zhan, Yong, Jia, Junhui, Xue, Pengchong, and Lu, Ran
- Subjects
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IMIDAZOLES , *ELECTROLUMINESCENCE , *CHEMICAL synthesis , *CHEMICAL derivatives , *CARBAZOLE , *PYRENE - Abstract
Highlights: [•] Synthesis of phenanthroimidazole derivatives with terminal carbazole or pyrene. [•] Photophysical properties of phenanthroimidazole derivatives. [•] Electroluminescent properties of phenanthroimidazole derivatives. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
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