Photophysical Properties of 7-(diethylamino)Coumarin-3-carboxylic Acid in the Nanocage of Cyclodextrins and in Different Solvents and Solvent Mixtures

2012 ◽  
Vol 89 (2) ◽  
pp. 280-293 ◽  
Author(s):  
Aninda Chatterjee ◽  
Debabrata Seth
Keyword(s):  
Carboxylic Acid ◽  
Photophysical Properties ◽  
Solvent Mixtures

Effects of Natural Cyclodextrins on the Photophysical Properties of Dibenzofuran-2-carboxylic Acid

2004 ◽  
Vol 108 (3) ◽  
pp. 392-402 ◽  
Author(s):  
Pablo R. Sainz-Rozas ◽  
José Ramón Isasi ◽  
Miguel Sánchez ◽  
Gloria Tardajos
Keyword(s):  
Carboxylic Acid ◽  
Photophysical Properties

Crystal Structures and Photophysical Properties of 9-Anthracene Carboxylic Acid Derivatives for Photomechanical Applications

2011 ◽  
Vol 11 (11) ◽  
pp. 4975-4983 ◽  
Author(s):  
Lingyan Zhu ◽  
Rabih O. Al-Kaysi ◽  
Robert J. Dillon ◽  
Fook S. Tham ◽  
Christopher J. Bardeen
Keyword(s):  
Carboxylic Acid ◽  
Crystal Structures ◽  
Photophysical Properties

Aggregation studies of benzoporphyrin derivative

2001 ◽  
Vol 79 (5-6) ◽  
pp. 1068-1074 ◽  
Author(s):  
David Delmarre ◽  
Noboru Hioka ◽  
Ron Boch ◽  
Ethan Sternberg ◽  
David Dolphin
Keyword(s):  
Dielectric Constant ◽  
Photodynamic Therapy ◽  
Photophysical Properties ◽  
Equilibrium Constants ◽  
Solvent Mixtures ◽  
Ph Values ◽  
Beer's Law ◽  
Beer’S Law ◽  
Solvent Systems ◽  
Porphyrin Dimers

The photophysical properties of a ring B benzoporphyrin derivative 1,3-diene dimethylester were investigated in solution (water–DMSO mixtures). At low proportions of water in DMSO, the diester obeys Beer's law at all pH values and ionic strengths investigated. For solvent systems containing more than 30% water, the extent of deviation from Beer's law as a function of porphyrin concentration is attributed to formation of porphyrin dimers. Dimerization equilibrium constants (Kd) have been determined in different percentage of solvent mixtures, using absorption and fluorescence spectroscopies, and were found to exhibit a linear correlation between log (Kd) and the inverse of the dielectric constant (log (Kd) = 24.6 – 1060.4 × 1/εmix). This equation permits the calculation of Kd in mixtures of water–DMSO.Key words: porphyrins, dimerization, aggregation, fluorescence, benzoporphyrin derivative, photodynamic therapy, photosensitizers.

scholarly journals ICT and AIE Characteristics Two Cyano-Functionalized Probes and Their Photophysical Properties, DFT Calculations, Cytotoxicity, and Cell Imaging Applications

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 585 ◽  
Author(s):  
Arup Tarai ◽  
Meina Huang ◽  
Pintu Das ◽  
Wenhui Pan ◽  
Jianguo Zhang ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Fluorescence Intensity ◽  
Emission Band ◽  
Density Functional ◽  
Cell Imaging ◽  
Photophysical Properties ◽  
High Water ◽  
Aggregation Behavior ◽  
Solvent Mixtures ◽  
Water Fractions

Two probes, AIE-1 and AIE-2, were synthesized to investigate the effect of substitutional functional group on aggregation (aggregation-caused quenching (ACQ) or aggregation-induced emission (AIE)) and intramolecular charge transfer (ICT) behavior as well as on the cell imaging aspect. The yellow-color non-substituted probe AIE-1 showed weak charge-transfer absorption and an emission band at 377 nm and 432 nm, whereas the yellowish-orange color substituted probe AIE-2 showed a strong charge-transfer absorption and an emission band at 424 nm and 477 nm in THF solvent. The UV-Vis studies of AIE-1 and AIE-2 in THF and THF with different water fractions showed huge absorption changes in AIE-2 with high water fractions due to its strong aggregation behavior, but no such noticeable absorption changes were observed for AIE-1. Interestingly, the fluorescence intensity of AIE-1 at 432 nm gradually decreased with increasing water fractions and became almost non-emissive at 90% water. However, the monomer-type emission of AIE-2 at 477 nm was shifted to 584 nm with a 6-fold increase in fluorescence intensity in THF-H2O (1:9, v/v) solvent mixtures due to the restriction of intramolecular rotation on aggregation in high water fractions. This result indicates that the probe AIE-1 shows ACQ and probe AIE-2 shows AIE behaviors in THF-H2O solvent mixtures. Furthermore, the emission spectra of AIE-1 and AIE-2 were carried out in different solvent and with different concentrations to see the solvent- or concentration-dependent aggregation behavior. Scanning electron microscope (SEM) and dynamic light scattering (DLS) experiments were also conducted to assess the morphology and particle size of two probes before and after aggregation. Both of the probes, AIE-1 and AIE-2, showed less toxicity on HeLa cells and were suitable for cell imaging studies. Density functional theory (DFT) calculation was also carried out to confirm the ICT process from an electron-rich indole moiety to an electron-deficient cyano-phenyl ring of AIE-1 or AIE-2.

scholarly journals Fluorescence and photostability studies of anthracene-9-carboxylic acid in different media

2000 ◽  
Vol 2 (1) ◽  
pp. 47-53 ◽  
Author(s):  
M. S. A. Abdel-Mottaleb ◽  
H. R. Galal ◽  
A. F. M. Dessouky ◽  
M. El-Naggar ◽  
D. Mekkawi ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Aqueous Media ◽  
Chemical Species ◽  
Ammonium Bromide ◽  
Solvent Mixtures ◽  
Photochemical Degradation ◽  
Acid Base ◽  
Photodegradation Rate ◽  
Acid Base Equilibrium ◽  
Cetyltrimethyl Ammonium

Electronic absorption and fluorescence spectra of anthracene-9-carboxylic acid (ANCA) were studied in different homogeneous solvents, binary protic/aprotic solvent mixtures and in heterogeneous solutions of the cationic cetyltrimethyl ammonium bromide (CTAB) micelle. Different chemical species of ANCA were identified spectroscopically in different media. The results are discussed on the basis of a mechanism that involves two equilibria: acid-base equilibrium and monomer-dimer equilibrium. These equilibria were found to be very sensitive to the nature of the medium and the concentration of ANCA.Moreover, while it is photostable in most solvents studied, the ANCA was found to be photolabile in aqueous media of different pHs. The acid-base catalyzed photodegradation rate was studied by following up absorption and/or fluorescence intensities as a function of illumination dose. The determined rate of the photochemical degradation of ANCA depends on the nature of the medium. The first order degradation rate constant is remarkably enhanced in heterogeneous medium of CTAB. As expected, the determined activation energy is low (∼3.2 kJ.mol-1). This result favors photooxidation process. Anthraquinone was the main photodegradation product obtainedvia9,9′-dicarboxylic head-to-head dimer of anthracene that was identified by GC-Mass technique.

Cyclometalated Ir(III) Complexes Containing Pyrazole/Pyrazine Carboxylate Ligands

2011 ◽  
Vol 64 (5) ◽  
pp. 561 ◽  
Author(s):  
Tanima Hajra ◽  
Jitendra K. Bera ◽  
Vadapalli Chandrasekhar
Keyword(s):  
Carboxylic Acid ◽  
Dicarboxylic Acid ◽  
Room Temperature ◽  
Photophysical Properties ◽  
Emission Spectra ◽  
Carboxylate Ligands ◽  
Ancillary Ligands

Two cyclometalated Ir(iii) complexes using 2-phenylpyridine (ppy-H) as the cyclometalating ligand, and pyrazole-3-carboxylic acid (prca-H) and pyrazine 3,5-dicarboxylic acid (pzdca-H2) as ancillary ligands; were synthesized from the chloro-bridged dimer precursor [{(ppy)2Ir}2(μ-Cl)2]. The title compounds [Ir(ppy)2(prca)] (1) and [{Ir(ppy)2}2(pzdca)] (2) are monomeric and dimeric neutral Ir(iii) complexes, respectively. Their electrochemical and photophysical properties were examined. They exhibit metal-based oxidations and ligand-based reductions. These complexes exhibit emission in the blue-green region with lifetimes in the micro-second range at room temperature. The nature of the emission spectra indicates differences in the origin of emission in these two compounds.

scholarly journals The remarkable influence of M2δ to thienyl π conjugation in oligothiophenes incorporating MM quadruple bonds

2008 ◽  
Vol 105 (40) ◽  
pp. 15247-15252 ◽  
Author(s):  
G. T. Burdzinski ◽  
M. H. Chisholm ◽  
P.-T. Chou ◽  
Y.-H. Chou ◽  
F. Feil ◽  
...  
Keyword(s):  
Thin Films ◽  
Carboxylic Acid ◽  
Energy Gap ◽  
Photophysical Properties ◽  
Visible Region ◽  
Triplet States ◽  
Relaxation Dynamics ◽  
Dual Emission ◽  
Molybdenum Complexes ◽  
Quadruple Bonds

Oligothiophenes incorporating MM quadruple bonds have been prepared from the reactions between Mo2(TiPB)4 (TiPB = 2,4,6-triisopropyl benzoate) and 3′,4′-dihexyl-2,2′-:5′,2″-terthiophene-5,5″-dicarboxylic acid. The oligomers of empirical formula Mo2(TiPB)2(O2C(Th)-C4(n-hexyl)2S-(Th)CO2) are soluble in THF and form thin films with spin-coating (Th = thiophene). The reactions between Mo2(TiPB)4 and 2-thienylcarboxylic acid (Th-H), 2,2′-bithiophene-5-carboxylic acid (BTh-H), and (2,2′:5′,2″-terthiophene)-5-carboxylic acid (TTh-H) yield compounds of formula trans-Mo2(TiPB)2L2, where L = Th, BTh, and TTh (the corresponding thienylcarboxylate), and these compounds are considered as models for the aforementioned oligomers. In all cases, the thienyl groups are substituted or coupled at the 2,5 positions. Based on the x-ray analysis, the molecular structure of trans-Mo2(TiPB)2(BTh)2 reveals an extended Lπ-M2δ-Lπ conjugation. Calculations of the electronic structures on model compounds, in which the TiPB are substituted by formate ligands, reveal that the HOMO is mainly attributed to the M2δ orbital, which is stabilized by back-bonding to one of the thienylcarboxylate π* combinations, and the LUMO is an in-phase combination of the thienylcarboxylate π* orbitals. The compounds and the oligomers are intensely colored due to M2δ–thienyl carboxylate π* charge transfer transitions that fall in the visible region of the spectrum. For the molybdenum complexes and their oligomers, the photophysical properties have been studied by steady-state absorption spectroscopy and emission spectroscopy, together with time-resolved emission and transient absorption for the determination of relaxation dynamics. Remarkably, THF solutions the molybdenum complexes show room-temperature dual emission, fluorescence and phosphorescence, originating mainly from 1MLCT and 3MM(δδ*) states, respectively. With increasing number of thienyl rings from 1 to 3, the observed lifetimes of the 1MLCT state increase from 4 to 12 ps, while the phosphorescence lifetimes are ≈80 μs. The oligomers show similar photophysical properties as the corresponding monomers in THF but have notably longer-lived triplet states, ≈200 μs in thin films. These results, when compared with metallated oligothiophenes of the later transition elements, reveal that M2δ–thienyl π conjugation leads to a very small energy gap between the 1MLCT and 3MLCT states of <0.6 eV.

Cholesteryl oleate-appended phthalocyanines as potential photosensitizers in the treatment of leishmaniasis

2015 ◽  
Vol 19 (01-03) ◽  
pp. 320-328 ◽  
Author(s):  
Laura E. Sánchez Contreras ◽  
Johannes Zirzlmeier ◽  
Sabrina V. Kirner ◽  
Francesca Setaro ◽  
Fernando Martínez ◽  
...  
Keyword(s):  
Excited State ◽  
Singlet Oxygen ◽  
Cutaneous Leishmaniasis ◽  
Photophysical Properties ◽  
Cholesteryl Oleate ◽  
Solvent Mixtures ◽  
Water Impact ◽  
Ldl Particles

Two phthalocyanines (Pcs) with either a zinc or a ruthenium metal at the center of the macrocycle have been functionalized by a cholesteryl oleate moiety. The potential photosensitizers (PSs) for the treatment of cutaneous leishmaniasis have been studied on their photophysical properties and their ability to generate singlet oxygen. These experiments corroborate that solvent mixtures containing variable ratios of THF and water impact the excited state deactivation. The compounds were used preloaded into LDL particles and their phototoxic activity was evaluated in a preliminary way.

Sign in / Sign up

Export Citation Format

Share Document