Synthesis and spectral properties of coumarins derivatives fluorescence emitters: Experiment and DFT/TDDFT calculations (original) (raw)
Related papers
3-(p-nitrophenyl)Coumarin derivatives: Synthesis, linear and nonlinear optical properties
Optical Materials, 2019
A serie of 3-(p-nitrophenyl)coumarin derivatives have been synthesized, characterized using 1 H, 13 C NMR and FT-IR spectroscopy and systematically analyzed by means of confocal optical microscopy as well as second harmonic generation (SHG) microscopy. A red shift of photophysical properties and an enhancement of the dipole moment of the dyes after excitation indicate that the emission is mainly caused by an intramolecular charge transfer (ICT). A positive solvatochromism and an increase in the fluorescence intensity have been detected in various solvents. Theoretical calculations based on the DFT and TDDFT theories have been performed in the aim to better understand the correlation between structural, electronic and photophysical properties of the synthesized dyes. The non-linear optical response of all the dyes has been also examined. Efficient NLO responses have been proved and showed a strong dependence on the chemical structure.
Spectrochimica Acta Part A-molecular and Biomolecular Spectroscopy, 1995
4-Alkyl-and 7-alkoxycoumarin derivatives have been investigated for their spectroscopic properties in three different solvents. The substituents are methyl, ethyl, propyl and butyl groups. Absorption and emission spectra, quantum yields and mean fluorescence decay times have been determined. The spectroscopic studies together with calculations of the radiative transition probabilities indicate that the 4-alkyl-and 7-alkoxy substituents do not change the symmetry of the electronic cloud of the coumarin skeleton. The changes observed for the rates of radiative transitions and also for the positions of the absorption and emission maxima can be explained by changes in the molecular electronic transition moment, caused by the weak donation potential of the substituents. A strong dependence of the quantum yields and mean fluorescence decay times on solvent viscosity has been found, leading to the suggestion that torsional rotations of the alkyl and alkoxy substituents significantly increase the internal non-radiative energy conversion rate.
Molecules
A set of 3-ethynylaryl coumarin dyes with mono, bithiophenes and the fused variant, thieno [3,2-b] thiophene, as well as an alkylated benzotriazole unit were prepared and tested for dye-sensitized solar cells (DSSCs). For comparison purposes, the variation of the substitution pattern at the coumarin unit was analyzed with the natural product 6,7-dihydroxycoumarin (Esculetin) as well as 5,7-dihydroxycomarin in the case of the bithiophene dye. Crucial steps for extension of the conjugated system involved Sonogashira reaction yielding highly fluorescent molecules. Spectroscopic characterization showed that the extension of conjugation via the alkynyl bridge resulted in a strong red-shift of absorption and emission spectra (in solution) of approximately 73–79 nm and 52–89 nm, respectively, relative to 6,7-dimethoxy-4-methylcoumarin (λabs = 341 nm and λem = 410 nm). Theoretical density functional theory (DFT) calculations show that the Lowest Unoccupied Molecular Orbital (LUMO) is mostly...
Journal of Physical Organic Chemistry, 2019
The electronic inductive, mesomeric, and electromeric substituent effects on the electronic absorption and fluorescence spectra of eleven substituted coumarins have been quantitatively studied by means of structure-reactivity relationships. The Hammett, Brown-Okamoto, and Yukawa-Tsuno correlations have been applied to the coumarins electronic absorption and fluorescence spectra wavenumbers, and Stokes shifts. The Stokes shift of coumarins decreased when the substituent electron-donor inductive/ mesomeric power increased.
Effect of substituents on the fluorescence and absorption spectra of coumarins
Spectrochimica Acta Part A: Molecular Spectroscopy, 1988
The absorption and fluorescence ernlsslon of substituted coumarms have been studied m different solvents It IS observed that the substituents alter both the absorption and fluorescence emission maxlma These shifts are discussed in terms of the change m mobility of n-electrons caused by the nature and position of the substltuent group m the parent compound
Comptes Rendus Chimie, 2006
The optical properties of two new iminocoumarin dyes, bearing a cyano group at the 3-position and an N-diethylamino group at the 7-position, were studied by UV-vis absorption and fluorescence spectroscopy in a large number of solvents. Dye 1 bears a free imino group, while dye 2 is substituted by an ethoxycarbonyl group on the imino function. The properties of these dyes were compared with those of 3-cyano-7-diethylaminocoumarin (3). The study shows that the three compounds display close spectroscopic behaviour in a large range of solvents, but the iminocoumarins exhibit much better fluorescence efficiency than the coumarin in polar and moderately protic solvents. This shows that iminocoumarin derivatives can advantageously replace coumarins in this type of solvents, and confirms that substitution on the imino group is a convenient way to obtain good fluorescent probes designed for various purposes. To cite this article: H. Turki et al., C. R. Chimie 9 (2006).
Journal of Chemical Sciences, 2017
Nonlinear optical properties of 3-styryl and 3-vinyl coumarin dyes have been investigated with Density Functional Theory (DFT) using global hybrid (GH) and range-separated hybrid (RSH) functionals. The performance of GHs-B3LYP, BHHLYP, PBE0, M06, M06L, M062X, and M06HF and RSHs-CAM-B3LYP, HISSbPBE, HSEH1PBE, wB97, wB97X, and wB97XD in combination with 6-311++G(d,p) basis set has been analyzed. Estimated (hyper) polarizability (α 0 , β 0) obtained from the GHs-M06, M062X and PBE0 are in agreement with each other. The RSHs-wB97 and wB97X estimate very close values of β 0. The β 0 value of 3-styryl and 3-vinyl coumarins reaches the maximum as the bond length alternation and bond order alternation parameters tend to zero. Natural bond orbital analysis shows there is extensive charge transfer in the excited state leading to large value of β 0. The vibrational contribution to α 0 and β 0 is significantly less when the donor is methoxy group and acceptor is nitro group in the 3-styryl coumarin. The dye, (E)-7-(diethylamino)-3-(4nitrostyryl)-2H-chromen-2-one (3c) is found to give the highest NLO response. An increasing electrophilicity originating from the decreased HOMO-LUMO band gap leads to an increase in α 0 and β 0 in all the cases.
Synthesis of novel fluorinated coumarins: Excellent UV-light excitable fluorescent dyes
Bioorganic & Medicinal Chemistry Letters, 1998
Two new fluorinated fluorescent dyes, 6,8-difiuoro-7-hydroxy-4-methylcoumarin (Marina Blue TM) and 3-carboxy-6,8-difluoro-7-hydroxycoumarin (Pacific BlueTM), exhibit excellent photophysical properties among a series of novel fluorinated 7-hydroxycoumarins. Most of these fluorinated coumarins have quantum yields (0.63 to 0.89) equal to or higher than that of the parent compound (0.63), which, in combination with their lower pK, s and higher photostability, make them superior fluorescent dyes for use as reporter molecules in biological systems.
Optical properties of new fluorescent iminocoumarins: Part 1
Dyes and Pigments, 2007
The optical properties of 10 new iminocoumarin dyes, bearing a cyano group at the 3-position, were studied in CH 2 Cl 2 by UV/vis absorption and fluorescence spectroscopy. Five of the dyes bear a free imino group, and differ by the nature and position of their electron-donor group. Among them, the dye bearing a diethylamino group at the 7-position displayed the most interesting optical properties. All the compounds were compared to analogues containing an ethoxycarbonyl group on the imino function. The presence of the ethoxycarbonyl group systematically induced a shift of the absorption and emission spectra towards long wavelengths. For the three dyes where charge transfer is weak, substitution reduced fluorescence efficiency. In contrast, the fluorescence quantum yield and lifetime were slightly increased for the compounds with strong charge transfer, and especially for that bearing a diethylamino group at the 7-position. This shows that substitution on the imino group can be a convenient way to obtain good fluorescent probes designed for various purposes.
Synthesis and Characterization of N-Coumarin Derivatives for Organic Light-Emitting Diodes (OLEDs)
2010
In this work, a series of new emissive materials based on pyrene substituted thiophenyl N-coumarins was developed for use in organic light-emitting diodes. The designed four molecules namely CTnP and CTnCP (n = 1-2) having thiophene moieties in the molecules up to two units were synthesized using a combination of condensation, bromination, Suzuki cross-coupling and Ullmann coupling reactions. Their chemical structures were confirmed by NMR techniques. The optical properties were measured by UV-Vis and fluorescence spectroscopy. Major absorption and emissive bands at λmax 420-480 nm and λmax 520-535 nm were observed, respectively. These peaks exhibit a red shift as the number of thiophene moiety increasing from 1 to 2 units. They are highly fluorescence with emission colors varying from green to orange. With the same the thiophene unit, molecules bearing carbazole-pyrenes substituent showed blue shifted spectra compared to those having pyrene. The CV measurements exhibited reversible...