The Experts below are selected from a list of 5877 Experts worldwide ranked by ideXlab platform
Fafu Yang - One of the best experts on this subject based on the ideXlab platform.
-
Triphenylene-fluorescein-Triphenylene trimers: novel columnar liquid crystals with solid fluorescence
Liquid Crystals, 2020Co-Authors: Ying Chen, Hongyu Guo, Fafu YangAbstract:This paper reported the first Triphenylene-fluorescein-Triphenylene trimers (3a and 3b), which exhibited stable hexagonal columnar mesophase and good fluorescence in comparison with the similar tri...
-
Bowl liquid crystal based on cyclotriveratrylene derivatives with multiple Triphenylene units: The influences of the numbers of Triphenylene units on mesomorphic behaviors
Journal of Molecular Liquids, 2018Co-Authors: Shibing Chen, Hongyu Guo, Xiaotong Geng, Fafu YangAbstract:Abstract Series of novel CTV derivatives with one, two and three Triphenylene units were designed and synthesized via click reaction in 72–84% yields. The influences of the numbers of Triphenylene units on mesomorphic behaviors were investigated. The results suggested that one Triphenylene unit could not counteract the rigidity of CTV skeleton, resulting in no mesophase for CTV derivative 6 with one Triphenylene unit. The strong induction of more Triphenylene units leaded to the mesophase for CTV derivative 7 with two Triphenylene units and 8 with three Triphenylene units. The more Triphenylene units decreased the phase transition temperatures. The XRD analysis suggested that compound 8 possessed higher ordered hexagonal columnar mesophase than compound 7, implying that the more Triphenylene units were favorable for improving the structural symmetry and produced the ordered columnar stacking. Compound 8 was the first example of high ordered hexagonal columnar liquid crystalline molecule based on CTV skeleton.
-
Near-infrared fluorescent and columnar liquid crystal: synthesis, and photophysical and mesomorphic properties of Triphenylene-Bodipy-Triphenylene triad
RSC Advances, 2017Co-Authors: Xiaoting Fang, Fafu Yang, Hongyu Guo, Jianrong LinAbstract:The first near-infrared fluorescent and columnar liquid crystal based on Bodipy was achieved by modifying 3,5-alkenyl substituted Bodipy with two Triphenylene units. Triphenylene-Bodipy-Triphenylene triad with 3,5-alkenyl groups exhibited hexagonal columnar mesophase and near-infrared fluorescence at 650–800 nm with the quantum yield of 31%.
-
Triphenylene perylene Triphenylene triads with bay substituents synthesis mesomorphism and electron transfer properties
Tetrahedron Letters, 2016Co-Authors: Hongyu Guo, Mingguang Zhu, Zusheng Wang, Fafu YangAbstract:Abstract Three novel Triphenylene–perylene–Triphenylene triads 5 , 6, and 7 with short amido spacer and bay-substituents (H, Br, and tert -butylphenyl) were synthesized in yields of 40–70%. Their structural and conformational characterization had been achieved by FT-IR, NMR, and HR-MS. The studies of liquid crystalline behaviors suggested that triads 5 , 6, and 7 possessed hexagonal columnar mesophase. The bay-substituents were favorable for decreasing the phase transitions temperature and enlarging the ranges of phase transfer temperatures. Their absorption spectra were similar to the absorption bands of analogues of Triphenylene and perylene. Their fluorescence spectra exhibited strong Dexter electron transfer between Triphenylene moiety and perylene moiety, resulting in drastic fluorescence quenching. The larger π–π conjugated system of perylene core enhanced the electron transfer property.
-
Triphenylene–perylene–Triphenylene triads with bay-substituents: synthesis, mesomorphism, and electron transfer properties
Tetrahedron Letters, 2016Co-Authors: Hongyu Guo, Mingguang Zhu, Zusheng Wang, Fafu YangAbstract:Abstract Three novel Triphenylene–perylene–Triphenylene triads 5 , 6, and 7 with short amido spacer and bay-substituents (H, Br, and tert -butylphenyl) were synthesized in yields of 40–70%. Their structural and conformational characterization had been achieved by FT-IR, NMR, and HR-MS. The studies of liquid crystalline behaviors suggested that triads 5 , 6, and 7 possessed hexagonal columnar mesophase. The bay-substituents were favorable for decreasing the phase transitions temperature and enlarging the ranges of phase transfer temperatures. Their absorption spectra were similar to the absorption bands of analogues of Triphenylene and perylene. Their fluorescence spectra exhibited strong Dexter electron transfer between Triphenylene moiety and perylene moiety, resulting in drastic fluorescence quenching. The larger π–π conjugated system of perylene core enhanced the electron transfer property.
Hongyu Guo - One of the best experts on this subject based on the ideXlab platform.
-
Triphenylene-fluorescein-Triphenylene trimers: novel columnar liquid crystals with solid fluorescence
Liquid Crystals, 2020Co-Authors: Ying Chen, Hongyu Guo, Fafu YangAbstract:This paper reported the first Triphenylene-fluorescein-Triphenylene trimers (3a and 3b), which exhibited stable hexagonal columnar mesophase and good fluorescence in comparison with the similar tri...
-
Bowl liquid crystal based on cyclotriveratrylene derivatives with multiple Triphenylene units: The influences of the numbers of Triphenylene units on mesomorphic behaviors
Journal of Molecular Liquids, 2018Co-Authors: Shibing Chen, Hongyu Guo, Xiaotong Geng, Fafu YangAbstract:Abstract Series of novel CTV derivatives with one, two and three Triphenylene units were designed and synthesized via click reaction in 72–84% yields. The influences of the numbers of Triphenylene units on mesomorphic behaviors were investigated. The results suggested that one Triphenylene unit could not counteract the rigidity of CTV skeleton, resulting in no mesophase for CTV derivative 6 with one Triphenylene unit. The strong induction of more Triphenylene units leaded to the mesophase for CTV derivative 7 with two Triphenylene units and 8 with three Triphenylene units. The more Triphenylene units decreased the phase transition temperatures. The XRD analysis suggested that compound 8 possessed higher ordered hexagonal columnar mesophase than compound 7, implying that the more Triphenylene units were favorable for improving the structural symmetry and produced the ordered columnar stacking. Compound 8 was the first example of high ordered hexagonal columnar liquid crystalline molecule based on CTV skeleton.
-
Near-infrared fluorescent and columnar liquid crystal: synthesis, and photophysical and mesomorphic properties of Triphenylene-Bodipy-Triphenylene triad
RSC Advances, 2017Co-Authors: Xiaoting Fang, Fafu Yang, Hongyu Guo, Jianrong LinAbstract:The first near-infrared fluorescent and columnar liquid crystal based on Bodipy was achieved by modifying 3,5-alkenyl substituted Bodipy with two Triphenylene units. Triphenylene-Bodipy-Triphenylene triad with 3,5-alkenyl groups exhibited hexagonal columnar mesophase and near-infrared fluorescence at 650–800 nm with the quantum yield of 31%.
-
Triphenylene perylene Triphenylene triads with bay substituents synthesis mesomorphism and electron transfer properties
Tetrahedron Letters, 2016Co-Authors: Hongyu Guo, Mingguang Zhu, Zusheng Wang, Fafu YangAbstract:Abstract Three novel Triphenylene–perylene–Triphenylene triads 5 , 6, and 7 with short amido spacer and bay-substituents (H, Br, and tert -butylphenyl) were synthesized in yields of 40–70%. Their structural and conformational characterization had been achieved by FT-IR, NMR, and HR-MS. The studies of liquid crystalline behaviors suggested that triads 5 , 6, and 7 possessed hexagonal columnar mesophase. The bay-substituents were favorable for decreasing the phase transitions temperature and enlarging the ranges of phase transfer temperatures. Their absorption spectra were similar to the absorption bands of analogues of Triphenylene and perylene. Their fluorescence spectra exhibited strong Dexter electron transfer between Triphenylene moiety and perylene moiety, resulting in drastic fluorescence quenching. The larger π–π conjugated system of perylene core enhanced the electron transfer property.
-
Triphenylene–perylene–Triphenylene triads with bay-substituents: synthesis, mesomorphism, and electron transfer properties
Tetrahedron Letters, 2016Co-Authors: Hongyu Guo, Mingguang Zhu, Zusheng Wang, Fafu YangAbstract:Abstract Three novel Triphenylene–perylene–Triphenylene triads 5 , 6, and 7 with short amido spacer and bay-substituents (H, Br, and tert -butylphenyl) were synthesized in yields of 40–70%. Their structural and conformational characterization had been achieved by FT-IR, NMR, and HR-MS. The studies of liquid crystalline behaviors suggested that triads 5 , 6, and 7 possessed hexagonal columnar mesophase. The bay-substituents were favorable for decreasing the phase transitions temperature and enlarging the ranges of phase transfer temperatures. Their absorption spectra were similar to the absorption bands of analogues of Triphenylene and perylene. Their fluorescence spectra exhibited strong Dexter electron transfer between Triphenylene moiety and perylene moiety, resulting in drastic fluorescence quenching. The larger π–π conjugated system of perylene core enhanced the electron transfer property.
Sandeep Kumar - One of the best experts on this subject based on the ideXlab platform.
-
Novel Triphenylene−ammonium−ammonium−Triphenylene-based discotic ionic liquid crystalline dimers
Liquid Crystals, 2012Co-Authors: Satyam Kumar Gupta, Sandeep KumarAbstract:In this work, two novel Triphenylene−ammonium−ammonium−Triphenylene diads were synthesised. The effect of the peripheral chain length around Triphenylene and the length of the linker connecting Triphenylene with an ammonium moiety on the liquid crystalline behaviour was studied. The molecular structures were verified using proton and carbon nuclear magnetic resonance, mass spectrometry and elemental analysis. The liquid crystalline properties of these compounds were determined by polarising optical microscopy, differential scanning calorimetry and X-ray diffraction studies. These Triphenylene−ammonium-based gemini dimers with tetrafluoroborate as the counter ion were found to exhibit liquid crystalline behaviour with a hexagonal columnar phase morphology.
-
Novel benzene-bridged Triphenylene-based discotic dyads.
The journal of physical chemistry. B, 2009Co-Authors: Satyam Kumar Gupta, V. A. Raghunathan, V. Lakshminarayanan, Sandeep KumarAbstract:We report the synthesis and characterization of two series of novel Triphenylene-based benzene-bridged symmetric discotic dimers. Two Triphenylene discotics have been connected to a rigid benzene ring via flexible methylene spacers. In one series, Triphenylene moiety was tethered with benzene via an ester linkage, while in the second series it is via an ether linkage. Within each series, the orientation of the linkage of the Triphenylene core around the benzene core has been changed by substituting the benzene ring at o-, m-, and p-positions. These materials have been characterized from their spectral and elemental analysis. The thermotropic liquid crystalline properties were investigated by polarizing optical microscopy, differential scanning calorimetry, and X-ray diffraction studies. All the virgin compounds do not display any mesomorphism; however, their charge transfer complexes with trinitrofluorenone, an electron acceptor, exhibited columnar mesophases. The direct current (dc) conductivity of charge transfer complexes at two ratios has been studied at variable temperature. The small conductivity value demonstrates that long spacers as well as connectivity to the rigid benzene ring dilute the column packing, hence making π-π interaction less efficient for the entire column length. A hexagonal assembly of Triphenylene-benzene dimer 12 on a highly oriented pyrolytic graphite (HOPG) surface has been visualized with scanning tunneling microscopy (STM).
-
novel conducting nanocomposites synthesis of Triphenylene covered gold nanoparticles and their insertion into a columnar matrix
Soft Matter, 2007Co-Authors: Sandeep Kumar, Santanu Kumar Pal, Suresh P Kumar, V. LakshminarayananAbstract:Gold nanoparticles fully covered with Triphenylene-based discotic liquid crystals (DLCs) were synthesized and dispersed in a columnar matrix. The thermophysical properties of these nanocomposites, studied using polarizing optical microscopy, differential scanning calorimetry and small angle X-ray diffraction studies (SAXS), confirm their insertion into the columnar matrix. The presence of the gold nanoparticles in the Triphenylene-based DLCs does not disturb the nature of the mesophase other than altering the transition temperatures. We propose that the gold nanoparticles are distributed between the domain gaps of the DLCs in random disordered manner. Interestingly the DC conductivity measurements show an enhancement of the electrical conductivity by more than a million times upon doping of the discotic liquid crystals with the Triphenylene-capped nanoparticles under ambient conditions.
-
Triphenylene based discotic liquid crystal dimers oligomers and polymers
Liquid Crystals, 2005Co-Authors: Sandeep KumarAbstract:Discotic liquid crystals are unique nanostructures with remarkable electronic and optoelectronic properties. Triphenylene derivatives play a major role in the research on discotic liquid crystals. Following recent reviews of the chemistry of Triphenylene‐based monomeric liquid crystals, this article now reviews the chemistry and physical properties of Triphenylene‐based discotic dimeric, oligomeric and polymeric liquid crystals.
-
Synthesis and characterization of novel imidazolium-based ionic discotic liquid crystals with a Triphenylene moiety
Tetrahedron Letters, 2005Co-Authors: Sandeep Kumar, Santanu Kumar PalAbstract:Abstract Two novel Triphenylene-tethered imidazolium salts were synthesized either by the quaternization of 1-methylimidazole with an ω-bromo-substituted Triphenylene or by the quaternization of a Triphenylene-substituted imidazole with methyl iodide. Their chemical structures were determined by 1 H NMR, 13 C NMR, IR, UV spectroscopy and elemental analysis. The thermotropic liquid crystalline properties of these salts were investigated by polarizing optical microscopy and differential scanning calorimetry. These Triphenylene-based imidazolium salts with bromide or iodide as counterion show columnar mesophase properties over a wide temperature range.
Jianwei Xie - One of the best experts on this subject based on the ideXlab platform.
-
Novel discotic liquid crystal oligomers: 1,3,5-triazine-based Triphenylene dimer and trimer with wide mesophase
Liquid Crystals, 2012Co-Authors: Fafu Yang, Jianwei Xie, Hongyu GuoAbstract:Series of novel 1,3,5-triazine-based Triphenylene oligomers 7, 10 and 12 with large bridging polyaromatic core were designed and synthesised by simple procedures in high yields. Their structures were confirmed by FTIR, 1H NMR, ESI-MS and elemental analyses. Their mesomorphic behaviours were studied by differential scanning calorimetry, polarising optical microscopy and X-ray diffraction. 1,3,5-triazine-based Triphenylene monomer 7 has no mesomorphic property, but 1,3,5-triazine-based Triphenylene dimer 10 and 1,3,5-triazine-based Triphenylene trimer 12 possess excellent mesomorphic properties. The mesomorphic temperature range of compound 12 was as wide as 180°C. These studies indicated that the mesomorphic properties were determined by the numbers of Triphenylene units. More units of Triphenylene in the oligomers resulted in better mesomorphic properties.
-
Novel symmetrical triads of Triphenylene-calix[4]arene-Triphenylene: synthesis and mesomorphism
Tetrahedron Letters, 2012Co-Authors: Fafu Yang, Hongyu Guo, Jianwei XieAbstract:Abstract Two novel symmetrical triads of Triphenylene-calix[4]arene-Triphenylene bridged by aromatic amido or hydrazone spacers were synthesized with stepwise procedures in yields of 67% and 68%, respectively. They exhibited interesting mesomorphic behavior of Triphenylene column with calix[4]arene units on ancillary lateral sides.
-
Synthesis of Calixarene-Linked Discotic Triphenylene
European Journal of Organic Chemistry, 2011Co-Authors: Fafu Yang, Hongyu Guo, Jianwei Xie, Jianrong LinAbstract:The syntheses of new macrocyclic molecules containing calixarene and discotic Triphenylene units in good yields are reported. Structural and conformational characterization of these new compounds was achieved by UV/Vis, FTIR, and NMR spectroscopy; mass spectrometry; and elemental analysis. The liquid-crystalline behavior was studied by polarizing optical microscopy, differential scanning calorimetry, and X-ray diffraction. The symmetrical calix[4]arene-linked Triphenylene dimer with a C10 chain (2b) exhibited the liquid-crystalline behavior of a calixarene bowlic column with two Triphenylene units as ancillary lateral columns.
Keqing Zhao - One of the best experts on this subject based on the ideXlab platform.
-
discotic mesogens based on Triphenylene fused benzimidazole or perimidine facile synthesis mesomorphism optical properties and self assembly
Liquid Crystals, 2020Co-Authors: Shengyuan Fan, Dongmei Fang, Keqing Zhao, Chun Feng, Shikai Xiang, Biqin WangAbstract:Four new mesomorphic Triphenylene-fused nitrogen-containing heterocyclic systems, including three benzimidazole and one perimidine derivatives with extended Triphenylene core of different sizes are...
-
Star-shaped oligomers with truxenone centre and Triphenylene branches: mesomorphism, optical and electronic properties
Liquid Crystals, 2020Co-Authors: Wen Zhang, Biqin Wang, Chun Feng, Shikai Xiang, Keqing ZhaoAbstract:Three star-shaped oligomers with an electron-deficient truxenone (TrO) as the central core and three electron-rich Triphenylenes (TP) as the peripheral arms were prepared, in which the Triphenylene...
-
discotic mesogens based on Triphenylene fused benzimidazole or perimidine facile synthesis mesomorphism optical properties and self assembly
Liquid Crystals, 2019Co-Authors: Hongtian Xu, Qianggen Li, Dongmei Fang, Keqing Zhao, Wenhao Yu, Chun Feng, Shikai Xiang, Ping Hu, Biqin WangAbstract:ABSTRACTFour new mesomorphic Triphenylene-fused nitrogen-containing heterocyclic systems, including three benzimidazole and one perimidine derivatives with extended Triphenylene core of different s...
-
Facile transformation of 1-arylTriphenylenes into dibenzo[fg,op]tetracenes by intramolecular Scholl cyclodehydrogenation: synthesis, self-assembly, and charge carrier mobility of large π-extended discogens
Journal of Materials Chemistry C, 2017Co-Authors: Keqing Zhao, Biqin Wang, Min Jing, Yan-hong Wang, Hirosato Monobe, Benoît Heinrich, Bertrand DonnioAbstract:The search for new organic semiconductors with enhanced charge transport properties and self-organizing abilities plays a pivotal role in the development of new applications in the emerging field of organic electronics. We have synthesized two series of discotic mesogenic materials derived from hexasubstituted Triphenylene, including (i) 1-aryl-2,3,6,7,10,11-hexakis(pentyloxy)Triphenylenes (14 new compounds) by a Suzuki cross-coupling reaction between the appropriate 1-bromoTriphenylene precursor and various arylboronic acids and (ii) unsymmetrical facial dibenzo[fg,op]tetracene discotic molecules (11 new compounds) by an FeCl3-oxidized cyclodehydrogenation reaction of the former. The mesomorphism has been investigated by polarizing optical microscopy, differential scanning microscopy, and small-angle X-ray scattering. Most aryl-substituted Triphenylene derivatives exhibit a single hexagonal columnar mesophase, enantiotropic over small temperature ranges or monotropic, with this low stability being likely attributed to the free-rotating bulky side-on arene group that disrupts a perfect stacking. The corresponding more rigid and flat dibenzo[fg,op]tetracene derivatives also self-organize into a hexagonal columnar mesophase, but with a larger mesophase stability than their parents, and occurring slightly above room temperature. The UV/vis absorption and fluorescence emission spectra have been measured. Tetracenes show stronger photoluminescence than arylTriphenylene in solution, while the reversed is observed in thin films, where a strong excimer emission for one of the polar 1-arylTriphenylenes is observed. The charge carrier mobility of two representative discogens has been measured by the time-of-flight photocurrent technique. The results show that the discogen with a lateral nucleus dipole displays a hole mobility of 10−4 cm2 V−1 s−1 in the mesophase, while the non-polar compound exhibits a hole mobility of 10−2 cm2 V−1 s−1 in its metastable-induced ordered phase. The charge carrier mobility is discussed as a function of the supramolecular organization.
-
mesogen jacketed liquid crystalline polyacetylene containing Triphenylene discogen synthesis and phase structure
Polymer Chemistry, 2013Co-Authors: Zhenqiang Yu, Keqing Zhao, Erqiang Chen, Bing-shi Li, Shuang Yang, Ben Zhong TangAbstract:Triphenylene-containing acetylenes with one or three methylene units as spacers and the corresponding mesogen-jacketed liquid crystalline polyacetylenes (MJLCPAs) were designed and synthesized, the mesomorphic properties and phase behaviors of the monomers and novel side-chain liquid crystalline polymers were investigated. The monomers [HCC(CH2)mC18H6(OC6H13)5; m = 1, 3] are prepared by consecutive etherization, coupling, and etherization reactions, and the chemical structures were confirmed by mass spectroscopy and 1H/13C-NMR. The phase behaviors of the monomers were investigated by differential scanning calorimetry (DSC), polarized light microscopy (PLM), and wide-angle X-ray diffraction (WAXD). The results show that both of the monomers form a hexagonal columnar liquid crystal phase at room temperature. The monomers are polymerized using [Rh(nbd)Cl]2 as catalyst and producing soluble polymers in the yields of 55% and 52%, respectively. The chemical structures and phase behaviors of the two polymers are characterized and evaluated by IR, NMR, TGA, DSC, and WAXD analyses. Both of the two polymers show enhanced thermal and chemical stability with thermal decomposition temperatures up to higher than 340 °C due to the protection of the “jacketed effect” of the side-chain Triphenylenes wrapped around the rigid polyacetylene main-chain. The polymers adopt a columnar shaped structure and self-organized into hexagonally packed columnar phase. The relative electron density maps of the columnar structure are also reconstructed.
