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1.
Fluorescence emission properties of substituted 3-styrylindoles viz 3-(2-phenylethenyl-E)-NH-indole (1), 3-[2-(4-cyanophenyl)ethenyl-E]-NH-indole (2), and 3-(2-cyano-2-phenylethenyl-Z]-NH-indole (3) in n-hexane, THF–H2O binary mixtures and solid state are reported. In general, fluorescence efficiency in solid state is found to be much higher than in n-hexane solution. The fluorescence enhancement in solid state is attributed to restricted intramolecular motions. Interestingly, the molecules of 3 in solid state are also bound together through intermolecular hydrogen bonds yielding polymer like structure, leading to further enhancement of fluorescence emission. In THF–H2O binary mixtures, drastic enhancement of fluorescence efficiency is observed due to aggregate formation. 相似文献
2.
Elisabete M. S. Castanheira M. Solange D. Carvalho Daniel J. G. Soares Paulo J. G. Coutinho Ricardo C. Calhelha Maria-João R. P. Queiroz 《Journal of fluorescence》2011,21(3):911-922
Fluorescence properties of four new potential antitumoral compounds, 3-arylbenzothieno[2,3-c]pyran-1-ones, were studied in solution and in lipid membranes of dipalmitoyl phosphatidylcholine (DPPC), egg yolk phosphatidylcholine
(Egg-PC) and dioctadecyldimethylammonium bromide (DODAB). The 3-(4-methoxyphenyl)benzothieno[2,3-c]pyran-1-one (1c) exhibits the higher fluorescence quantum yields in all solvents studied. All compounds present a solvent sensitive emission,
with significant red shifts in polar solvents for the methoxylated compounds. The results point to an ICT character of the
excited state, more pronounced for compound 1c. Fluorescence (steady-state) anisotropy measurements of the compounds incorporated in liposomes of DPPC, DODAB and Egg-PC
indicate that all compounds have two different locations, one due to a deep penetration in the lipid membrane and another
corresponding to a more hydrated environment. In general, the methoxylated compounds prefer hydrated environments inside the
liposomes. The 3-(4-fluorophenyl)benzothieno[2,3-c]pyran-1-one (1a) clearly prefers a hydrated environment, with some molecules located at the outer part of the liposome interface. On the
contrary, the preferential location of 3-(2-fluorophenyl)benzothieno[2,3-c]pyran-1-one (1b) is in the region of lipid hydrophobic tails. Compounds with a planar geometry (1a and 1c) have higher mobility in the lipid membranes when phase transition occurs. 相似文献
3.
The use of fluorescent solid films of a 1-(p-butyloxyphenyl)-4-(p-cyanophenyl)buta-1E, 3E-diene as an efficient temperature sensor is described. The fluorescence changes in these films are proposed to occur due
to a reversible temperature-dependent variation in its monomer-aggregate ratio. Photoisomerization of the butadiene chromophore
in solid films was observed to occur only at elevated temperatures (> 120∘C), making the material also useful for reversible photochemical generation of fluorescence patterns with nondestructive readout
properties. 相似文献
4.
Three new pyridylindolizine derivatives, 1, 2, 3-tricarbometoxi-7-(4-pyridyl)-pyrrolo[1, 2-a]pyridine (I), 1,2-dicarboethoxy-3-(4-bromobenzoyl)-7-(4-pyridyl)-pyrrolo[1,2-a]pyridine (II) and its isomer 1,2-dicarboethoxy-3- (4-bromobenzoyl) -5- (2-pyridyl) -pyrrolo[1, 2-a]pyridine (III) have been investigated in different solutions by UV-VIS absorption, steady-state, and time-resolved fluorescence methods. The effects of the substituent and solvent on the spectroscopic properties have been demonstrated. The fluorescence decay data could be fitted to a single-exponential function. The lifetime values are higher in protic polar than in aprotic apolar solvents for compound I. In the case of compounds II and III the fluorescence intensities and lifetimes are very low, with the exception of III in aprotic solvents. The absorption and fluorescence properties of the compounds showed a solvent dependence. 相似文献
5.
Pyrazolo[3,4-b]pyridines having 4-chloro-5-chloroethyl side chain are synthesized by the reaction of 5-aminopyrazole and cyclic β-formylester
gave aminopyrazolodihydrofuranone intermediate, which on cyclization in phosphorous oxychloride exclusively converted in to
4-chloro-5-chloroethyl pyrazolo[3,4-b]pyridines 4(a-b) in major amount. The side chain with acetic acid, thiourea and aromatic amines are used to form angular ring leads to formation
of tricyclic Furo[2,3-d]pyrazolo[2,3-b]pyridines 5(a-b), pyrazolo[3,4-b]thieno[2,3-d]pyridines 6(a-b) and pyrazolo[3,4-b]pyrrolo[2,3-d]pyridines 7(a-n) respectively. The substituents effect at C4 position on fluorescence properties of pyrazolopyridines has been studied. Moreover the effect of electron donor and halogen
substituents on fluorescence properties of pyrazolopyrrolopyridines 7(a-n) has been investigated along with their fluorescent quantum yield. 相似文献
6.
Four novel copper(II) complexes of the composition [CuLX] where L = 2,6-bis(benzimidazole-2yl)pyridine, X = dipyridophenazine
(L1), 1,10-phenanthroline (L2), hydroxyproline (L3) and 2,6-pyridine dicarboxylic acid (L4) were synthesized and characterized by using elemental analysis, FT-IR, UV–vis, ESI-MS, molar conductance and magnetic susceptibility
measurements. The complexes [CuLL1](NO3)2 [1], [CuLL2](NO3)2 [2], [CuLL3](NO3) [3] and [CuLL4] (NO3) [4] are stable at room temperature. In DMSO the complexes [1] and [2] are 1:2 electrolytes, [3] and [4] are 1:1 electrolytes. Based on elemental and spectral studies five coordinated geometry is assigned to all the four complexes.
The interaction of four copper ion complexes with calf thymus DNA were carried out by UV–vis titrations, fluorescence spectroscopy,
thermal melting and viscosity measurements .The binding constant (Kb) of the above four metal complexes were determined as 5.43 × 104 M,−1 2.56 × 104 M−1, 1.21 × 104 M−1 and 1.57 × 104 M−1 respectively. Quenching studies of the four complexes indicates that these complexes strongly bind to DNA, out of all complex
1 is binding more strongly. Viscosity measurements indicate the binding mode of complexes with CT DNA by intercalation through
groove. Thermal melting studies also support intercalative binding. The nuclease activity of the above metal complexes shows
that 1, 2 and 3 complexes cleave DNA through redox chemistry. 相似文献
7.
Yanling Si Yuqi Liu Godefroid Gahungu Xiaochun Qu Zhijian Wu 《Molecular physics》2013,111(24):3716-3725
DFT/TDDFT calculations were carried out to investigate the electronic structures, absorption and phosphorescence properties of a series of heteroleptic Ir(III) complexes consisting of two N-heterocyclic carbene ligands and a conjugated bicyclic N,N′-heteroaromatic (N?N) ligand. On the basis of the results reported herein, we attempt to explain the experimental observations according to which complex (mpmi)2Ir(pybi) (1) [Hmpmi = 1-(4-tolyl)-3-methyl-imidazole; Hpybi = 2-(pyridin-2-yl)-1H-benzo[d]imidazole] emits green light with an extremely high-quantum phosphorescence efficiency (Φ PL ) of 79.3%, while a relatively lower Φ PL (only 11%) was measured for (fpmi)2Ir(tfpypz) (2) [fpmi = 1-(4-fluorophenyl)-3-methylimdazolin-2-ylidene-C, C2′; tfpypz = 2-(3-(trifluoromethyl)-1H-pyrazol-5-yl)pyridinato] emitting blue light by tuning the N?N ligands. Besides, we also designed (fpmi)2Ir(pyN3) (3) [pyN3H = 2-(5-(trifluoromethyl)-2H-1,2,4-triazol-3-yl)pyridine] and (fpmi)2Ir(pyN4) (4) [pyN4H = 2-(1H-tetrazol-5-yl)pyridine] to explore the influence of electron-withdrawing substituents on N?N ligands on the electronic and optical properties of these Ir(III) complexes. The results revealed that electron-withdrawing substituents can stabilise both HOMOs and LUMOs and induce HOMO–LUMO energy gap change. Moreover, the emission properties can be significantly tuned by introducing different N?N ligands. While new insights were gained on structural and electronic properties, the extremely high Φ PL of 1 was found to be not inherent to spin-orbital coupling effects, but determined by its large transition dipole moment (μS 1) upon S 0–S 1 transition compared with that of 2. On the basis of these results, the designed complexes 3 and 4 are considered to be the promising candidates for blue-emitting phosphorescence materials with higher Φ PL than the complex 2. 相似文献
8.
Aaron JJ Párkányi C Adenier A Potin C Zajíčková Z Martínez OR Svoboda J Pihera P Váchal P 《Journal of fluorescence》2011,21(6):2133-2141
The electronic absorption, fluorescence excitation and emission spectra, and fluorescence quantum yields of novel fused thienobenzofurans,
including thieno[3,2-b][1]benzofuran (1), [1]benzothieno[3,2-b]furan (2), and [1]benzothieno[3,2-b][1]benzofuran (3), were recorded in fourteen solvents of different polarities at room temperature. Compound 2 was not fluorescent. Experimental ground-state dipole moments of compounds 1–3 were measured in benzene at 298 K and compared with the corresponding theoretical dipole moment values. The solvent effects
on the electronic absorption and fluorescence spectra of these thienobenzofurans were quantitatively investigated by means
of solvatochromic correlations based on the Kawski-Chamma-Viallet and McRae equations. A weak negative solvatochromic behavior
was found for these compounds, showing that their dipole moments are slightly lower in the excited singlet-state than in the
ground-state. Kamlet-Abboud-Taft multiparameter relationships were also established for electronic absorption and fluorescence
wavenumbers, and fluorescence quantum yields in most solvents, demonstrating the occurrence of specific solute-solvent interactions. 相似文献
9.
Synthesis and Fluorescence Studies of Some New Fluorophores and Their Effect on Hybridization of Oligodeoxyribonucleotides 总被引:1,自引:1,他引:0
Some novel fluorophores, viz. 6-(6-isobutyrylamino-1,3-dioxo-1H,3H-benzo[de]isoquinolin-2-yl)-hexanoic acid (1), 6-(6-dimethylamino-1,3-dioxo-1H, 3H-benzo[de]isoquinolin-2-yl)-hexanoic acid (2), 6-(6-benzoylamino-1, 3-dioxo-1H, 3H-benzo[de]isoquinolin-2-yl)-hexanoic acid (3), 6-(6-amino-1-oxo-1H, 3H-benzo[de]isoquinolin-2-yl)-hexanoic acid (4) and 6-(6-amino-1H,3H-benzo[de] isoquinolin-2-yl)-hexanoic acid (5) have been designed, synthesized and characterized. Their comparative fluorescence has been studied in different organic
solvents and aqueous solutions containing inorganic ions. Out of these, two fluorophores, 1 and 2 have been used for labelling of nucleosides which were finally converted into their phosphoramidites, and used for labelling
of oligodeoxyribonucleotides through covalent attachment. These fluorophores after attachment on oligodeoxyribonucleotides
showed good fluorescence signals and higher hybridisation affinity than unlabelled oligodeoxyribonucleotides. 相似文献
10.
Xinying Zhang Dongfang Li Xuesen Fan Xia Wang Xiaoyan Li Guirong Qu Jianji Wang 《Molecular diversity》2010,14(1):159-167
The utilization of an ionic liquid, [bmim][BF4] as both reaction medium and promoter for a multi-component reaction of aldehyde (1) and 5-amino-3-methyl-1-phenylpyrazole (2) with Meldrum acid (3) or dimedone (5) is studied. From this reaction, pyrazolo[3,4-b]pyridinone (4) and pyrazolo[3,4-b]quinolinone (6) derivatives were prepared in high yields. This novel procedure showed such advantages as environmentally benign nature,
enhanced efficiency, simple operation process, and mild reaction conditions. As an application, the procedure was successfully
used in the preparation of a set of pyrimidine nucleoside–pyrazolo[3,4-b]pyridine and pyrazolo[3,4-b]quinolinone hybrids with potential biological activities. 相似文献
11.
Patil NR Melavanki RM Kapatkar SB Ayachit NH Saravanan J 《Journal of fluorescence》2011,21(3):1213-1222
The absorption and fluorescence spectra of three Carboxamides namely (E)-2-(4-Chlorobenzylideneamino)-N-(2-chlorophenyl)-4,
5, 6, 7-tetrahydrobenzo[b]thiophene-3-carboxamide (C1), (E)-N-(3-Chlorophenyl)-2-(3, 4-dimethoxybenzylideneamino)-4, 5, 6, 7-tetrahydrobenzo[b]thiophene-3-carboxamide (C2) and (E)-N-(3-Chlorophenyl)-2-(3, 4, 5-trimethoxybenzylideneamino)-4, 5, 6, 7-tetrahydrobenzo[b]thiophene-3-carboxamide (C3) have been recorded at room temperature in solvents of different polarities using dielectric constant (ε) and refractive
index (n). Experimental ground (μg) and excited (μe) state dipole moments are estimated by means of solvatochromic shift method and also the excited dipole moments are estimated
in combination with ground state dipole moments. It was estimated that dipole moments of the excited state were higher than
those of the ground state of all three molecules. Further, the changes in dipole moment (Dm \Delta \mu ) were calculated both from solvatochromic shift method and on the basis of microscopic empirical solvent polarity parameter
(ETN E_T^N ) and the values are compared. 相似文献
12.
Salman A. Khan 《Journal of fluorescence》2017,27(3):929-937
2-amino-4-(4-bromophenyl)-8-methoxy-5,6-dihydrobenzo[h]quinoline-3-carbonitrile (ABDC) was synthesized by the reaction of (2E)-2-(4 bromobenzylidene) - 6 -methoxy-3,4-dihydronaphthalen-1(2H)-one (Chalcone) with malononitrile and ammonium acetate under microwave irradiation. Chalcone was synthesised by the reaction 4-bromobenzaldehyd, 6-methoxy-1,2,3,4-tetrahydro-naphthalin-1-one under the same condition. Structure of ABDC was conformed by 1H and 13C NMR, FT-IR, EI-MS spectral studies and elemental analysis. The electronic absorption and fluorescence spectra of ABDC have been studied in solvents of different polarities, and the data were used to study the solvatochromic properties such as excitation coefficient, stokes shift, oscillator strength, transition dipole moment and fluorescence quantum yield. The absorption maximum and fluorescence emission maximum was observed red shift when increase solvent polarity n-Hexane to DMSO. ABDC undergoes solubilization in different micelles and may be used as a probe and quencher to determine the critical micelle concentration (CMC) of CTAB and SDS. The anti-bacterial activity of chalcone and its cyclized product ABDC was tested in vitro by the disk diffusion assay against two Gram-positive and two Gram-negative bacteria was determined with the reference of standard drug Tetracycline. Results showed that the ABDC is better anti-bacterial agent as compared to chalcone. The anti-bacterial activity was further supported by the quantum chemistry calculation. 相似文献
13.
Anna???gowska Dawid?D?bowski Adam?Lesner Magdalena?Wysocka Krzysztof?Rolka 《Molecular diversity》2010,14(1):51-58
A peptomeric library consisting of 360 monocyclic analogues of trypsin inhibitor SFTI-1 isolated from sunflower seeds was
designed and synthesized by a solid-phase approach in order to select chymotrypsin and cathepsin G inhibitors. All peptomers
contained a proteinogenic-Phe-mimicking N-benzylglycine (Nphe) at positions 5 and 12. Into the synthesized library, different peptoid monomers were introduced in the
7–10 segment. Deconvolution of the library against both proteinases through an iterative method in solution revealed that
the strongest chymotrypsin inhibitory activity was displayed by two analogues, [Nphe5,12]SFTI-1 (1) and [Nphe5,12, Naem8]SFTI-1 (2), where Naem stands for N-(2-morpholinoethyl)glycine. After deconvolution against a cathepsin G analogue, [Nphe5,12, Npip8,9, Nnle10] SFTI-1 (3) (Npip = N-(3,4-methylenedioxybenzyl)glycine) appeared to be the most potent inhibitor with a high serum stability. It is worth noting
that the analogues obtained by a combinatorial approach display high specificity towards one of the experimental enzymes.
Another interesting feature is the lack of Pro8 in analogues 2 and 3, the amino acid residue absolutely conserved in the family of Bownan–Birk inhibitors. 相似文献
14.
Madhukar N. Jachak Sandeep M. Bagul Dilip R. Birari Maruti G. Ghagare Muddassar A. Kazi Raghunath B. Toche Vijayavitthal T. Mathad 《Journal of fluorescence》2010,20(3):787-796
A rapid and efficient method for the synthesis of novel dipyrazolo[3,4-b:3′,4′-d]pyridines (DPP) from pyrazolo[3,4-b]pyridine was successfully developed. The DPP derivative was further N-alkylated (6, 8) as well as N-linked with amino acids (13) and their photophysical properties were studied along with N-aryl DPP 4 and observed that the chromophores at C4 position in the aryl ring changed the absorption and emission λmax. 相似文献
15.
Naresh Kumar Mahalingavelar Paramasivam Jagdeep Kumar Anamika Gusain Prasanta Kumar Hota 《Journal of fluorescence》2018,28(5):1207-1216
Various electron donor and acceptor substituted (NO2, CN, Cl, H, OCH3, NH2) p-phenyl ethenyl-E- thiophenes (1–6) were synthesized and substituent dependent optical properties (dipole moment, transition dipole moment, oscillator strength, optical band gap, hyperpolarizability) were studied using Solvatochromism and Density functional theory. It is shown that thiophene acts as a weak electron donor in presence of an electron withdrawing p-phenyl substituent (NO2, CN, Cl), whereas thiophene acts as a weak electron acceptor in presence of an electron donating p-phenyl substituent (OCH3, NH2). In comparison to ethenyl thiophene 4, the HOMO-LUMO energy band gap is decreased upon increasing the electron donating or electron withdrawing capacity of p-phenyl substituent. From the excited state dipole moment calculation, it is shown that the excited state is highly dipolar for nitro and amino compounds 1 and 6, whereas compounds 2–5 show a non-polar excited state. As compared to the ethenyl thiophene 4, the first hyperpolarizability (β) increases upon substitution either with a strong electron withdrawing or strong electron donating p-phenyl substituent. A large β value is found for p-nitro phenyl ethenyl-E-thiophene and p-amino phenyl ethenyl-E- thiophene. Overall, these studies provide useful information in understanding the optical properties of phenyl and heterocyclic based ethenyl systems. 相似文献
16.
3‐(4‐Nitrophenylethenyl‐E)‐NH‐indole ( 1 ), 3‐(4‐nitrophenyl ethenyl‐E)‐N‐acetylindole ( 2 ), and 3‐(4‐nitrophenylethenyl‐E)‐N‐benzenesulfonylindole ( 3 ) are relatively less fluorescent in organic solvents, with fluorescence quantum yield (Φf) in the range of 0.002 to 0.066 depending on the solvent polarity. However, in bovine serum albumin (BSA)‐phosphate buffer, the fluorescence of these compounds gets drastically enhanced with Φf in the range of 0.21 to 0.67, depending on the substituent on the indolic nitrogen atom. Additionally, linear increase in the fluorescence intensity of 2 and 3 occurs on increasing the BSA concentration. These fluorescence properties together with the neutral, hydrophobic nature of these compounds make these fluorophores good fluorescence probe for studying the micropolarity of proteins like BSA and in general the ligand–protein interactions. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
17.
A series of benzo[b][1,8]naphthyridines has been synthesized by Friedl?nder condensation of 2-aminoquinoline-3-carbaldehyde 1 (o-aminoaldehyde) with alicyclic ketones in basic medium. Benzonaphthyridines branched with various side-chains and substituents
are prepared with the aim of being investigated as a good fluorescent material. Electronic absorption and fluorescence properties
of some representative benzonaphthyridines in organic solvents, water-dioxane, and SDS, CTAB and Triton-X-100 micelles have
been examined. The linear correlation between solvent polarity and fluorescence properties is observed. This study may provide
new directions for the development of fluorescence probes as reporters of microenvironments of organized assemblies. 相似文献
18.
We have explored the thermoluminescence (TL) properties of a few series of liquid crystal unsymmetrical and symmetrical azomethines and poly(azomethines) with different shapes. Rod-, bent- and star-shaped compounds were investigated as thermoluminescent detectors. All of the investigated compounds, except ASB3, AG2 and PAZ2, exhibited mesomorphic behavior. The thermoluminescence studies have shown that molecular structure of the compound along with shape influenced the TL properties of azomethines and poly(azomethines). Thermoluminescence intensity (I), temperature of maximum TL (T), activation energy values (E) and frequency factor (s) were detected. For the first time, to the best of our knowledge, thermoluminescence properties of liquid crystalline azomethines and polyazomethines were described and compared in this article. 相似文献
19.
81Br NQR frequencies and differential scanning calorimetry (DSC) were measured as a function of temperature. [NH3(CH2)4 NH3]CdBr4 (1) and [NH3(CH2)5NH3]CdBr4 (2) showed a doublet and quartet 81Br NQR spectrum, respectively. [NH3(CH2)5NH3]ZnBr4 (3) and [NH3(CH2)6NH3]ZnBr4 (4) exhibited a four-line 81Br NQR spectrum. From the NQR results, it is inferred that (1) and (2) consist of infinite two-dimensional sheets of corner-sharing CdBr6 octahedra, whereas (3) and (4) have isolated [ZnBr4]2− tetrahedra. All of the crystals except (1) showed at least one structural phase transition above 380 K. 相似文献
20.
Salem Saïd Noureddine Mhadhbi Fadhel Hajlaoui Samia Yahyaoui Alexander J. Norquist Tahar Mhiri 《Phase Transitions》2013,86(1):71-84
Single crystals of [(R)-C5H14N2][Cu(SO4)2(H2O)4]·2H2O (1) were grown through the slow evaporation of a solution containing H2SO4, (R)-C5H12N2 and CuSO4·5H2O. These crystals spontaneously transform to [(R)-C5H14N2]2[Cu(H2O)6](SO4)3 (2) over the course of four days at room temperature. The same single crystal on the same mounting was used for the determination of the structure of (1) and the unit cell determination of (2). A second single crystal of the transformed batch has served for the structural determination of (2). Compound 1 crystallizes in the noncentrosymmetric space group P21 (No. 4) and consists of trimeric [Cu(SO4)2(H2O)4]2? anions, [(R)-C5H14N2]2+ cations and occluded water molecules. Compound 2 crystallizes in P21212 (No. 18) and contains [Cu(H2O)6]2+ cations, [SO4]2? anions and occluded water molecules. The thermal decompositions of compounds 1 and 2 were studied by thermogravimetric analyses and temperature-dependent X-ray diffraction. 相似文献