scholarly journals A Way to Improve Luminescent Efficiency of Bis-Chalcone Derivatives

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Meng Guan Tay ◽  
Mee Hing Tiong ◽  
Ying Ying Chia ◽  
Suzie Hui Chin Kuan ◽  
Zhi-Qiang Liu
Keyword(s):  
Quantum Yield ◽  
Phenyl Ring ◽  
Unsaturated Ketone ◽  
Addition Compound ◽  
Polar Solvents ◽  
Chalcone Derivatives ◽  
Emission Efficiency ◽  
Nonpolar Solvents ◽  
Chalcone Derivative ◽  
Related Compounds

Chalcone related compounds have been reported as a poor luminescence molecule due to the quenching processes from the intramolecular torsional motions andcis-transisomerization in theα,β-unsaturated ketone moiety. Despite this limitation, we found a way to improve the luminescent efficiency of our bis-chalcone derivative. In this project, two series of bis-chalcone compounds have been synthesized through Claisen-Schmidt condensation by reacting terephthaldehyde or 2,5-dimethoxyterephthaldehyde with the respective R-acetophenone [where R = H (1aand2a) andortho-hydroxy (1band2b)] in 1 : 2 mole ratio. The presence of a methoxy (OMe) substituent on the central phenyl ring of bis-chalcone has weakened the C=C bond at theα,β-unsaturated ketone moiety of2aand2b. Interestingly, the OMe group has improved the emission efficiency of the bis-chalcone; that is, the quantum yield of1ain DCM solution was not able to be determined due to poor luminescence, but the quantum yield of2ain DCM solution was improved to 0.57. In addition, compound2aalso shows solvatochromism effect where theλmaxemission shifted from 499 nm in nonpolar solvents (benzene) to 523 nm in polar solvents (acetonitrile). This work provides another way to improve the emission efficiency of chalcone related compounds apart from using the complexation method which has been reported before.

scholarly journals Isomerization and Properties of Isomers of Carbocyanine Dyes

Sci ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 5 ◽  
Author(s):  
Pavel Pronkin ◽  
Alexander Tatikolov
Keyword(s):  
Phenyl Ring ◽  
Steric Effect ◽  
Cyanine Dyes ◽  
Information Storage ◽  
Polymethine Chain ◽  
Trans Isomers ◽  
Trans Form ◽  
Polar Solvents ◽  
Carbocyanine Dyes ◽  
Nonpolar Solvents

One of the important features of polymethine (cyanine) dyes is isomerization around one of C–C bonds of the polymethine chain. In this review, spectral properties of the isomers, photoisomerization and thermal back isomerization of carbocyanine dyes, mostly meso-substituted carbocyanine dyes, are considered. meso-Alkyl-substituted thiacarbocyanine dyes are present in polar solvents mainly as cis isomers and, hence, exhibit no photoisomerization, whereas in nonpolar solvents, in which the dyes are in the trans form, photoisomerization takes place. In contrast, the meso-substituted dyes 3,3′-dimethyl-9-phenylthiacarbocyanine and 3,3′-diethyl-9-(2-hydroxy-4-methoxyphenyl)thiacarbocyanine occur as trans isomers and exhibit photoisomerization in both polar and nonpolar solvents. The behavior of these dyes may be explained by the fact that the phenyl ring of the substituent in their molecules can be twisted at some angle, removing the substituent from the plane of the molecule and reducing its steric effect on the conformation of the trans isomer. In some cases, photoisomerization of cis isomers of meso-substituted carbocyanine dyes is also observed (for some meso-alkyl-substituted dyes complexed with DNA and chondroitin-4-sulfate; for 3,3′-diethyl-9-methoxythiacarbocyanine in moderate polarity solvents). The cycle photoisomerization–thermal back isomerization of cyanine dyes can be used in various systems of information storage and deserves further investigation using modern research methods.

Einfluß von Substituenten und polaren Lösungsmitteln auf die Deaktivierung des S1Zustandes bei Donator-Akzeptor-substituierten trans-Stilbenen/Influence of Substituents and Polar Solvents on the Deactivation of the First Excited Singlet of Donor-acceptor Substituted Trans-stilbenes

1980 ◽  
Vol 35 (12) ◽  
pp. 1411-1414 ◽  
Author(s):  
D. Gloyna ◽  
A. Kawski ◽  
I. Gryczyński
Keyword(s):  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Singlet State ◽  
Excited Singlet State ◽  
Excited Singlet ◽  
Polar Solvents ◽  
Effect Of Substituents ◽  
Nonpolar Solvents ◽  
Donor Acceptor ◽  
Influence Of Substituents

AbstractThe effect of substituents on the fluorescence quantum yield φf of trans-stilbenes (1) in dimethylformamide, acetonitrile, and n-propanol, as well as in n-heptane, is mainly due to radiationless deactivation. Contrary to n-heptane, the rate kd of radiationless deactivation in the above mentioned polar solvents for compounds 1 of similar structure is not a monotoneous function of the polarity of the first excited singlet state. The maximum of kd corresponds to compounds with medium polarity (1h, 1i). The effect of substituents on the fluorescence rate kfn in polar and nonpolar solvents is small compared to that on kd. In all solvents kfn drops with increasing polarity of the first excited singlet state.

scholarly journals Isomerization and Properties of Isomers of Carbocyanine Dyes

Sci ◽  
2019 ◽  
Vol 1 (1) ◽  
pp. 19 ◽  
Author(s):  
Pavel Pronkin ◽  
Alexander Tatikolov
Keyword(s):  
Trans Isomer ◽  
Phenyl Ring ◽  
Spectral Properties ◽  
Information Storage ◽  
Polymethine Chain ◽  
Trans Isomers ◽  
Trans Form ◽  
Polar Solvents ◽  
Carbocyanine Dyes ◽  
Nonpolar Solvents

One of the important features of polymethine (cyanine) dyes is isomerization about one of C–C bonds of the polymethine chain. In this review, spectral properties of the isomers, photoisomer-ization and thermal back isomerization of carbocyanine dyes, mostly meso-substituted carbocy-anine dyes, are considered. meso-Alkyl-substituted thiacarbocyanine dyes are present in polar solvents mainly as cis isomers and, hence, exhibit no photoisomerization, whereas in nonpolar solvents, in which the dyes are in the trans form, photoisomerization takes place. In contrast, the meso-substituted dyes 3,3′-dimethyl-9-phenylthiacarbocyanine and 3,3′-diethyl-9-(2-hydroxy-4-methoxyphenyl)thiacarbocyanine occur as trans isomers and exhibit photoisomerization in both polar and nonpolar solvents. The behavior of these dyes may be ex-plained by the fact that the phenyl ring of the substituent in their molecules can be twisted at some angle, removing the substituent from the plane of the molecule and reducing its steric ef-fect on the conformation of the trans isomer. In some cases, photoisomerization of cis isomers of meso-substituted carbocyanine dyes is also observed (for some meso-alkyl-substituted dyes com-plexed with DNA and chondroitin-4-sulfate; for 3,3′-diethyl-9-methoxythiacarbocyanine in moderate polarity solvents). The cycle photoisomerization–thermal back isomerization of cya-nine dyes can be used in various systems of information storage and deserves further investiga-tion using modern research methods.

scholarly journals Isomerization and Properties of Isomers of Carbocyanine Dyes

Sci ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 5
Author(s):  
Pavel Pronkin ◽  
Alexander Tatikolov
Keyword(s):  
Phenyl Ring ◽  
Steric Effect ◽  
Cyanine Dyes ◽  
Information Storage ◽  
Polymethine Chain ◽  
Trans Isomers ◽  
Trans Form ◽  
Polar Solvents ◽  
Carbocyanine Dyes ◽  
Nonpolar Solvents

One of the important features of polymethine (cyanine) dyes is isomerization around one of C–C bonds of the polymethine chain. In this review, spectral properties of the isomers, photoisomerization and thermal back isomerization of carbocyanine dyes, mostly meso-substituted carbocyanine dyes, are considered. meso-Alkyl-substituted thiacarbocyanine dyes are present in polar solvents mainly as cis isomers and, hence, exhibit no photoisomerization, whereas in nonpolar solvents, in which the dyes are in the trans form, photoisomerization takes place. In contrast, the meso-substituted dyes 3,3′-dimethyl-9-phenylthiacarbocyanine and 3,3′-diethyl-9-(2-hydroxy-4-methoxyphenyl)thiacarbocyanine occur as trans isomers and exhibit photoisomerization in both polar and nonpolar solvents. The behavior of these dyes may be explained by the fact that the phenyl ring of the substituent in their molecules can be twisted at some angle, removing the substituent from the plane of the molecule and reducing its steric effect on the conformation of the trans isomer. In some cases, photoisomerization of cis isomers of meso-substituted carbocyanine dyes is also observed (for some meso-alkyl-substituted dyes complexed with DNA and chondroitin-4-sulfate; for 3,3′-diethyl-9-methoxythiacarbocyanine in moderate polarity solvents). The cycle photoisomerization–thermal back isomerization of cyanine dyes can be used in various systems of information storage and deserves further investigation using modern research methods.

scholarly journals Regeneration of Spent Lubricant Refining Clays by Solvent Extraction

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Yan-zhen Wang ◽  
Hai-long Xu ◽  
Li Gao ◽  
Meng-meng Yan ◽  
Hong-ling Duan ◽  
...  
Keyword(s):  
Solvent Extraction ◽  
Petroleum Ether ◽  
Oil Recovery ◽  
Oil Refining ◽  
Lubricating Oil ◽  
Polar Solvents ◽  
Base Oil ◽  
Nonpolar Solvents ◽  
Total Oil ◽  
Storage Times

Step-by-step solvent extraction was used to regenerate spent clay by recovering the adsorbed oil in lubricating oil refining clay. Several polar and nonpolar solvents were tested, and petroleum ether (90–120°C) and ethanol (95 v%) were selected as the nonpolar and polar solvents, respectively. The spent clay was first extracted using petroleum ether (90–120°C) to obtain ideal oil and then extracted with a mixed solvent of petroleum ether (90–120°C) and ethanol (95 v%) two or three times to obtain nonideal oil before being extracted with ethanol and water. Finally, the clay was dried at 130°C to obtain regenerated clay. The total oil recovery can be more than 99 wt% of the adsorbed oil. The recovered ideal oil can be used as lubricating base oil. Shorter storage times for spent clay produce better regeneration results. The regenerated clay can be reused to refine the lubricating base oils.

Liquefaction Properties of Alanine Hydrosulfate Ionic Liquid on Pine

2014 ◽  
Vol 525 ◽  
pp. 177-180
Author(s):  
Jian Hua Huang ◽  
Hong Lu Xie ◽  
Guo Feng Zou
Keyword(s):  
Ionic Liquid ◽  
Fourier Transform ◽  
Sulfuric Acid ◽  
Orthogonal Experiment ◽  
Hydrogen Sulfate ◽  
Mass Ratio ◽  
Polar Solvents ◽  
Orthogonal Experiment Design ◽  
Nonpolar Solvents ◽  
Strong Acidity

Ionic liquid containing alanine cations and hydrogen sulfate was synthesized using alanine and sulfuric acid as materials. Fourier Transform Infrared Specctrometer was used to verify the final product. The results showed that the objective product was developed successfully. General properties of the final product were detected. The results showed that strong acidity, large viscosity, soluble in polar solvents and insoluble in nonpolar solvents were the products properties which were suitable for liquefying. The liquefaction rate of ionic liquid on pine was studied. Study the optimum liquefaction condition using the method of orthogonal experiment design. By stirring at 120°C for 2 hours using ionic liquid with the concentration of 80% and with the mass ratio of 30, liquefaction rate of ionic liquid on pine was high.

Proton Magnetic Resonance Spectra of Some Amphetamines and Related Compounds and Observations on Rotamer Populations

1971 ◽  
Vol 49 (19) ◽  
pp. 3143-3151 ◽  
Author(s):  
K. Bailey ◽  
A. W. By ◽  
K. C. Graham ◽  
D. Verner
Keyword(s):  
Hydrogen Bonding ◽  
Phenyl Ring ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Side Chain ◽  
Amino Group ◽  
Ortho Position ◽  
Electronic Effects ◽  
Related Compounds

Data from the p.m.r. spectra of β-amino-, β-aminohydrochloride-, β-hydroxy-, and β-nitro-α-phenyl-propanes having methyl or methoxy substituants on the phenyl ring (37 compounds in all) are presented. The α and β protons of the side-chain give a pattern usually analyzable as ABX. The data are discussed in terms of correlations of coupling constants and chemical shifts with electronegativity of the substituent groups, steric and electronic effects, and apparent changes in rotamer populations. Hydrogen-bonding between the amino group of amphetamines and a methoxyl function at the ortho position in the phenyl ring is indicated for the salts but not the free bases.

Electron-donating methoxyl group position effect on properties of diarylethene derivatives having a pyrazole unit

2007 ◽  
Vol 85 (1) ◽  
pp. 12-20 ◽  
Author(s):  
Tianshe Yang ◽  
Shouzhi Pu ◽  
Bing Chen ◽  
Jingkun Xu
Keyword(s):  
Quantum Yield ◽  
Electrochemical Properties ◽  
Phenyl Ring ◽  
Position Effect ◽  
Methoxyl Group ◽  
Strong Fluorescence ◽  
First Order ◽  
Group Position

New types of asymmetrical photochromic diarylethene derivatives having a pyrazole unit, namely 1-[1,3,5-trimethyl-1-pyrazol-4-yl],2-[2-methyl-5-(4-methoxylphenyl)-1-thien-3-yl]perfluorocyclopentene (1a), 1-[1,3,5-trimethylpyrazol-4-yl],2-[2-methyl-5-(3-methoxylphenyl)-1-thien-3-yl] perfluorocyclopentene (2a), 1-[1,3,5-trimethyl-pyrazol-4-yl],2-[2-methyl-5-(2-methoxylphenyl)-1-thien-3-yl]perfluorocyclopentene (3a), and 1-[1,3,5-trimethyl-pyrazol-4-yl],2-[2-methyl-5-phenyl-1-thien-3-yl]perfluorocyclopentene (4a), were synthesized. Their optical and electrochemical properties, such as photochromism, photochromic cyclization–cycloreversion kinetics, and fluorescence and electrochemical properties were investigated in detail. The results show that all of these compounds have good photochromism, high cycloreversion quantum yield, and relatively strong fluorescence. Their cyclization-cycloreversion processes were determined to be zeroth to first order reactions. The oxidations of diarylethenes 1a–4a were initiated at 0.73, 1.11, 0.79, and 1.03 V, respectively. Furthermore, introduction of the electron-donating methoxyl group at different positions of the terminal phenyl ring was found to strongly influence these optical and electrochemical properties.Key words: photochromism, diarylethene, electron-donating group, optical and electrochemical properties.

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