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1.
Synthesis,characterization and luminescent properties of europium complexes with 2,4,6‐tris‐(2‐pyridyl)‐s‐triazine as highly efficient sensitizers 下载免费PDF全文
Jie Kang Ying‐Nan Chen Ai‐Ling Wang Hai‐Yan Li Yan‐Rong Qu Hai‐Xia Zhang Hai‐Bin Chu Yong‐Liang Zhao 《Luminescence》2015,30(8):1360-1366
Using 2,4,6‐tris‐(2‐pyridyl)‐s‐triazine (TPTZ) as a neutral ligand, and p‐hydroxybenzoic acid, terephthalic acid and nitrate as anion ligands, five novel europium complexes have been synthesized. These complexes were characterized using elemental analysis, rare earth coordination titrations, UV/vis absorption spectroscopy and infrared spectroscopy. Luminescence spectra, luminescence lifetime and quantum efficiency were investigated and the mechanism discussed in depth. The results show that the complexes have excellent emission intensities, long emission lifetimes and high quantum efficiencies. The superior luminescent properties of the complexes may be because the triplet energy level of the ligands matches well with the lowest excitation state energy level of Eu3+. Moreover, changing the ratio of the ligands and metal ions leads to different luminescent properties. Among the complexes, Eu2(TPTZ)2(C8H4O4)(NO3)4(C2H5OH)·H2O shows the strongest luminescence intensity, longest emission lifetime and highest quantum efficiency. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
2.
Synthesis,crystal structure and fluorescence properties of terbium complexes with phenoxyacetic acid and 2,4,6‐tris‐(2‐pyridyl)‐s–triazine 下载免费PDF全文
Xiao‐Yan Wei Yan‐Rong Qu Bin Yue Jie Kang Hai‐Bin Chu Yong‐Liang Zhao 《Luminescence》2015,30(6):835-841
Two complexes of Tb3+, Gd3+/Tb3+ and one heteronuclear crystal Gd3+/Tb3+ with phenoxyacetic acid (HPOA) and 2,4,6‐tris‐(2‐pyridyl)‐s–triazine (TPTZ) have been synthesized. Elemental analysis, rare earth coordination titration, inductively coupled plasma atomic emission spectrometry (ICP‐AES) and thermogravimetric analysis‐differential scanning calorimetry (TG‐DSC) analysis show that the two complexes are Tb2(POA)6(TPTZ)2·6H2O and TbGd(POA)6(TPTZ)2·6H2O, respectively. The crystal structure of TbGd(POA)6(TPTZ)2·2CH3OH was determined using single‐crystal X‐ray diffraction. The monocrystal belongs to the triclinic system with the P‐1 space group. In particular, each metal ion is coordinately bonded to three nitrogen atoms of one TPTZ and seven oxygen atoms of three phenoxyacetic ions. Furthermore, there exist two coordinate forms between C6H5OCH2COO– and the metal ions in the crystal. One is a chelating bidentate, the other is chelating and bridge coordinating. Fluorescence determination shows that the two complexes possess strong fluorescence emissions. Furthermore, the fluorescence intensity of the Gd3+/Tb3+ complex is much stronger than that of the undoped complex, which may result from a decrease in the concentration quench of Tb3+ ions, and intramolecular energy transfer from the ligands coordinated with Gd3+ ions to Tb3+ ions. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
3.
《Luminescence》2003,18(3):162-172
The reaction of iron(III) tetrakis‐5,10,15,20‐(N‐methyl‐4‐pyridyl)porphyrin (Fe(III)TMPyP) with hydrogen peroxide (H2O2) and the catalytic activity of the reaction intermediates on the luminescent peroxidation of luminol in aqueous solution were studied by using a double‐mixing stopped‐flow system. The observed luminescence intensities showed biphasic decay depending on the conditions. The initial flashlight decayed within <1 s followed by a sustained emission for more than 30 s. Computer deconvolution of the time‐resolved absorption spectra under the same conditions revealed that the initial flashlight appeared during the formation of the oxo–iron(IV) porphyrin, TMPyPFe(IV) = O, which is responsible for the sustained emission. The absorption spectra 0.0–0.5 s did not reproduce well by a simple combination of the two spectra of Fe(III)TMPyP and TMPyPFe(IV) = O, indicating that transient species was formed at the initial stage. Addition of uric acid (UA) caused a significant delay in the initiation of the luminol emission as well as in the formation of the TMPyPFe(IV) = O. Both of them were completely diminished in the presence of UA equimolar with H2O2, while mannitol had no effect at all. The delay of the light emission as well as the appearance of TMPyPFe(IV) = O was directly proportional to the [UA]0 but other kinetic profiles were not changed significantly. Based on these observations and the kinetic analysis, we confirmed the involvement of the oxo–iron(IV) porphyrin radical cation, (TMPyP)·+Fe(IV) = O, as an obligatory intermediate in the rate‐determining step of the overall reaction, Fe(III)TMPyP + H2O2 → TMPyPFe(IV) = O, with a rate constant of k = 4.3 × 104/mol/L/s. The rate constants for the reaction between the (TMPyP)·+Fe(IV) = O and luminol, and between the TMPyPFe(IV) = O and luminol were estimated to be 3.6 × 106/mol/L/s and 1.31 × 104/mol/L/s, respectively. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
4.
The interactions of cobalt(II)–4‐[(5‐chloro‐2‐pyridyl)azo]‐1,3‐diaminobenzene (5‐Cl‐PADAB) complex with different kinds of homopolymer oligonucleotides in basic medium were investigated based on the measurements of resonance light scattering, UV–vis, circular dichroism spectra and dark field light‐scattering imaging. Experiments showed that only thymidine homopolymer (poly T) oligonucleotides with the length in the range of poly T6 to poly T18 could interact with the Co(II)–5‐Cl‐PADAB complex in alkaline conditions and cause evident color and spectral change. Thus, the binary complex of Co(II)–5‐Cl‐PADAB could be employed as a visual probe for selectively recognizing the poly T oligonucleotides. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
5.
《Luminescence》2003,18(5):259-267
High‐valent oxo‐iron(IV) species are commonly proposed as the key intermediates in the catalytic mechanisms of iron enzymes. Water‐soluble iron(III) tetrakis‐5,10,15,20‐(N‐methyl‐4‐pyridyl)porphyrin (Fe(III)TMPyP) has been used as a model of heme‐enzyme to catalyse the hydrogen peroxide (H2O2) oxidation of various organic compounds. However, the mechanism of the reaction of Fe(III)TMPyP with H2O2 has not been fully established. In this study, we have explored the kinetic simulation of the reaction of Fe(III)TMPyP with H2O2 and of the catalytic reactivity of FeTMPyP in the luminescent peroxidation of luminol. According to the mechanism that has been established in this work, Fe(III)TMPyP is oxidized by H2O2 to produce (TMPyP)·+Fe(IV)=O (k1 = 4.5 × 104/mol/L/s) as a precursor of TMPyPFe(IV)=O. The intermediate, (TMPyP)·+Fe(IV)=O, represented nearly 2% of Fe(III)TMPyP but it does not accumulate in suf?cient concentration to be detected because its decay rate is too fast. Kinetic simulations showed that the proposed scheme is capable of reproducing the observed time courses of FeTMPyP in various oxidation states and the decay pro?les of the luminol chemiluminescence. It also shows that (TMPyP)·+Fe(IV)=O is 100 times more reactive than TMPyPFe(IV)=O in most of the reactions. These two species are responsible for the initial sharp and the sustained luminol emissions, respectively. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
6.
Dan Wu Yanyan Han Qin Wei Yanfang Zhao Kexia Mao Yanyan Cai Ru Li Yuxue Dai 《Luminescence》2011,26(6):629-633
Based on the inhibition effect of transferrin (Tf) on the reaction of the luminol–hydrogen peroxide (H2O2) chemiluminescence (CL) system, catalysed by meso‐tetra‐(3‐methoxyl‐4‐hydroxyl) phenyl manganese porphyrin (MnP) as a mimetic enzyme of peroxides, a sensitive flow‐injection CL method has been developed for the determination of Tf in an alkaline medium. The CL reaction was carefully investigated by examining the variations of reaction conditions. Under optimum conditions, the linear range for the determination of transferrin was 0.04–20.0 μg/mL and the detection limit was 1.62 ng/mL. This proposed method was sensitive, convenient and simple, and has been successfully applied to the determination of transferrin in a serum sample. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
7.
A simple, rapid chemiluminescence (CL) method was described for the determination of piroxicam, a commonly used analgesic agent drug. A strong CL signal was detected when cerium(IV) sulphate was injected into tris‐(4,7‐diphenyl‐1,10‐phenanthrolinedisulphonic acid) ruthenium(II) (RuBPS)–piroxicam solution. The CL signal was proportional to the concentration of piroxicam in the range 2.8 × 10–8–1.2 × 10–5 mol/L. The detection limit was 2 × 10–8 mol/L and the relative standard deviation (RSD) was 3.7% (c = 7.0 × 10–7 mol/L piroxicam; n = 11). The proposed method was applied to the determination of piroxicam in pharmaceutical preparations in capsules, spiked serum and urine samples with satisfactory results. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
8.
Alexey S. Gorovoy Olga Gozhina John‐Sigurd Svendsen George V. Tetz Anna Domorad Victor V. Tetz Tore Lejon 《Journal of peptide science》2013,19(10):613-618
Tuberculosis is still affecting millions of people worldwide, and new resistant strains of Mycobacterium tuberculosis are being found. It is therefore necessary to find new compounds for treatment. In this paper, we report the synthesis and in vitro testing of peptidyl β‐aminoboronic acids and β‐aminoboronates with anti‐tubercular activity. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
9.
Incretinomimetic and Insulinomimetic Effect of (2E)‐N′‐(1′‐Naphthyl)‐3,4,5‐Trimethoxybenzohydrazide for Glycemic Homeostasis 下载免费PDF全文
Marisa Jádna Silva Frederico Alessandra Mascarello Allisson Jhonatan Gomes Castro Gabrielle Da Luz Delsi Altenhofen Camila Pires Mendes Paulo Cesar Leal Rosendo Augusto Yunes Ricardo José Nunes Fátima Regina Mena Barreto Silva 《Journal of cellular biochemistry》2016,117(5):1199-1209
10.
Synthesis and discovery of potent carbonic anhydrase,acetylcholinesterase, butyrylcholinesterase,and α‐glycosidase enzymes inhibitors: The novel N,N′‐bis‐cyanomethylamine and alkoxymethylamine derivatives 下载免费PDF全文
Parham Taslimi Cuneyt Caglayan Vagif Farzaliyev Oruj Nabiyev Afsun Sujayev Fikret Turkan Ruya Kaya İlhami Gulçin 《Journal of biochemical and molecular toxicology》2018,32(4)
During this investigation, N,N′‐bis‐azidomethylamines, N,N′‐bis‐cyanomethylamine, new alkoxymethylamine and chiral derivatives, which are considered to be a new generation of multifunctional compounds, were synthesized, functional properties were investigated, and anticholinergic and antidiabetic properties of those compounds were studied through the laboratory tests, and it was approved that they contain physiologically active compounds rather than analogues. Novel N‐bis‐cyanomethylamine and alkoxymethylamine derivatives were effective inhibitors of the α‐glycosidase, cytosolic carbonic anhydrase I and II isoforms, butyrylcholinesterase (BChE), and acetylcholinesterase (AChE) with Ki values in the range of 0.15–13.31 nM for α‐glycosidase, 2.77–15.30 nM for human carbonic anhydrase isoenzymes I (hCA I), 3.12–21.90 nM for human carbonic anhydrase isoenzymes II (hCA II), 23.33–73.23 nM for AChE, and 3.84–48.41 nM for BChE, respectively. Indeed, the inhibition of these metabolic enzymes has been considered as a promising factor for pharmacologic intervention in a diversity of disturbances. 相似文献
11.
The modes of binding of 5′‐[4‐(aminoiminomethyl)phenyl]‐[2,2′‐Bifuran]‐5‐carboximidamide (DB832) to multi‐stranded DNAs: human telomere quadruplex, monomolecular R‐triplex, pyr/pur/pyr triplex consisting of 12 T*(T·A) triplets, and DNA double helical hairpin were studied. The optical adsorption of the ligand was used for monitoring the binding and for determination of the association constants and the numbers of binding sites. CD spectra of DB832 complexes with the oligonucleotides and the data on the energy transfer from DNA bases to the bound DB832 assisted in elucidating the binding modes. The affinity of DB832 to the studied multi‐stranded DNAs was found to be greater (Kass ≈ 107M?1) than to the duplex DNA (Kass ≈ 2 × 105M?1). A considerable stabilizing effect of DB832 binding on R‐triplex conformation was detected. The nature of the ligand tight binding differed for the studied multi‐stranded DNA depending on their specific conformational features: recombination‐type R‐triplex demonstrated the highest affinity for DB832 groove binding, while pyr/pur/pyr TTA triplex favored DB832 intercalation at the end stacking contacts and the human telomere quadruplex d[AG3(T2AG3)3] accommodated the ligand in a capping mode. Additionally, the pyr/pur/pyr TTA triplex and d[AG3(T2AG3)3] quadruplex bound DB832 into their grooves, though with a markedly lesser affinity. DB832 may be useful for discrimination of the multi‐sranded DNA conformations and for R‐triplex stabilization. © 2009 Wiley Periodicals, Inc. Biopolymers 93: 8–20, 2010. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com 相似文献
12.
A new system for the determination of nucleic acid by rare earth metallic porphyrin of [tetra‐(3‐methoxy‐4‐hydroxyphenyl)]–Tb3+ [T(3‐MO‐4HP)–Tb3+] porphyrin as fluorescence spectral probe has been developed in this paper. Nucleic acid can enhance the fluorescence intensity of the T(3‐MO‐4HP)–Tb3+ porphyrin in the presence of bis(2‐ethylhexyl)sulfosuccinate sodium salt(AOT) micelle. In pH 8.00 Tris–HCl buffer solution, under optimum conditions, the enhanced fluorescence intensity is in proportion to the concentration of nucleic acids in the range of 0.05–3.00 µg mL?1 for calf thymus DNA (ct DNA) and 0.03–4.80 µg mL?1 for fish sperm DNA(fs DNA). Their detection limits are 0.03 and 0.01 µg mL?1, respectively. In addition, the binding interaction mechanism between T(3‐MO‐4HP)–Tb3+ porphyrin and ct DNA is also investigated by resonance scattering and fluorescence spectra. The maximum binding number is calculated by molar ratio method. The new system can be used for the determination of nucleic acid in pig liver, yielding satisfactory results. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
13.
A dysprosium‐zinc porphyrin, [DyZn(TPPS)H3O]n (1) (TPPS = tetra(4‐sulfonatophenyl)porphyrin), was prepared through solvothermal reactions and structurally characterized by single‐crystal X‐ray diffraction analyses. Complex 1 features a three‐dimensional (3‐D) porous open framework that is thermally stable up to 400 °C. Complex 1 displays a void space of 215 Å3, occupying 9.2% of the unit cell volume. The fluorescence spectra reveal that it shows an emission band in the red region. The fluorescence lifetime is 39 µsec and the quantum yield is 1.7%. The cyclic voltammetry (CV) measurement revealed one quasi‐reversible wave with E1/2 = 0.30 V. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
14.
APN/CD13 is over‐expressed by Psoriatic fibroblasts and is modulated by CGRP and IL‐4 but not by retinoic acid treatment 下载免费PDF全文
Pascale Gerbaud Jean Guibourdenche Rafika Jarray Marc Conti Patricia Palmic Stéphanie Leclerc‐Mercier Julie Bruneau Olivier Hermine Yves Lepelletier Françoise Raynaud 《Journal of cellular physiology》2018,233(2):958-967
15.
Synthesis,crystal structure and biological evaluation of spectroscopic characterization of Ni(II) and Co(II) complexes with N‐salicyloil‐N′‐maleoil‐hydrazine as anticholinergic and antidiabetic agents 下载免费PDF全文
Gulnar Gondolova Parham Taslimi Ajdar Medjidov Vagif Farzaliyev Afsun Sujayev Mansura Huseynova Onur Şahin Bahattin Yalçın Fikret Turkan İlhami Gulçin 《Journal of biochemical and molecular toxicology》2018,32(9)
[Ni(C11H9N2O5)2(H2O)2]?3(C3H7NO) ( 1 ) and [Co(C11H9N2O5)2(H2O)2]?3(C3H7NO) ( 2 ) are synthesized and characterized by elemental analysis, FT‐IR spectra, magnetic susceptibility, and thermal analysis. In addition, the crystal structure of Ni(II) complex is presented. Both complexes show distorted octahedral geometry. In 1 and 2, metal ions are coordinated by two oxygen atoms of salicylic residue and two nitrogen atoms of maleic amide residue from two ligands, and two oxygen atoms from two water molecules. In this paper, both compounds showed excellent inhibitory effects against human carbonic anhydrase (hCA) isoforms I, and II, α‐glycosidase, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE). Compounds 1 and 2 had Ki values of 18.36 ± 4.38 and 26.61 ± 7.54 nM against hCA I and 13.81 ± 3.02 and 29.56 ± 6.52 nM against hCA II, respectively. On the other hand, their Ki values were found to be 487.45 ± 54.18 and 453.81 ± 118.61 nM against AChE and 199.21 ± 50.35 and 409.41 ± 6.86 nM against BChE, respectively. 相似文献
16.
Structure of the Escherichia coli ArnA N‐formyltransferase domain in complex with N5‐formyltetrahydrofolate and UDP‐Ara4N 下载免费PDF全文
Nicholas A. Genthe James B. Thoden Hazel M. Holden 《Protein science : a publication of the Protein Society》2016,25(8):1555-1562
ArnA from Escherichia coli is a key enzyme involved in the formation of 4‐amino‐4‐deoxy‐l ‐arabinose. The addition of this sugar to the lipid A moiety of the lipopolysaccharide of pathogenic Gram‐negative bacteria allows these organisms to evade the cationic antimicrobial peptides of the host immune system. Indeed, it is thought that such modifications may be responsible for the repeated infections of cystic fibrosis patients with Pseudomonas aeruginosa. ArnA is a bifunctional enzyme with the N‐ and C‐terminal domains catalyzing formylation and oxidative decarboxylation reactions, respectively. The catalytically competent cofactor for the formylation reaction is N10‐formyltetrahydrofolate. Here we describe the structure of the isolated N‐terminal domain of ArnA in complex with its UDP‐sugar substrate and N5‐formyltetrahydrofolate. The model presented herein may prove valuable in the development of new antimicrobial therapeutics. 相似文献
17.
Aliye Altundas Berna Gül Murat Çankaya Ali Atasever İlhami Gülçin 《Journal of biochemical and molecular toxicology》2017,31(12)
The conversion of carbon dioxide (CO2) and bicarbonate (HCO3−) to each other is very important for living metabolism. Carbonic anhydrase (CA, E.C.4.2.1.1), a metalloenzyme familly, catalyzes the interconversion of these ions (CO2 and HCO3−) and are very common in living organisms. In this study, a series of novel 2‐amino‐3‐cyanopyridines supported with some functional groups was synthesized and tested as potential inhibition effects against both cytosolic human CA I and II isoenzymes (hCA I and II) using by Sepharose‐4B‐l ‐tyrosine‐sulfanilamide affinity chromatography. The structural elucidations of novel 2‐amino‐3‐cyanopyridines were achieved by NMR, IR, and elemental analyses. K i values of the novel synthesized compounds were found in range of 2.84–112.44 μM against hCA I and 2.56–31.17 μM against hCA II isoenzyme. While compound 7d showed the best inhibition activity against hCA I (K i: 2.84 μM), the compound 7b demonstrated the best inhibition profile against hCA II isoenzyme (K i: 2.56 μM). 相似文献
18.
Synthesis and Biological Evaluation of Novel 1‐(4‐(Hydroxy(1‐oxo‐1,3‐dihydro‐2H‐inden‐2‐ylidene)methyl)phenyl)‐3‐phenylurea Derivatives 下载免费PDF全文
A series of novel phenylurea containing 2‐benzoylindan‐1‐one derivatives 3a – 3j were synthesized from the reaction of phenylurea‐substituted acetophenones 1a – 1j with phthalaldehyde 2 under mild reaction conditions in good yields. All synthesized compounds were characterized by spectroscopic methods. The obtained compounds ( 3a – 3j ) were evaluated for anticancer activity against HeLa and C6 cell lines. Antiproliferative activity was determined by the BrdU proliferation ELISA assay, 3f and 3g were found to be most active compounds. The compounds were also screened for antimicrobial activity and all compounds showed remarkable activity against used microorganisms. 相似文献
19.
Synthesis and Deprotection of Biodegradably and Thermally Protected Dinucleoside‐2′,5′‐Monophosphate Prodrug Model of 2‐5A 下载免费PDF全文
Protected dinucleoside‐2′,5′‐monophosphate has been prepared to develop a prodrug strategy for 2‐5A. The removal of enzymatically and thermally labile 4‐(acetylthio)‐2‐(ethoxycarbonyl)‐3‐oxo‐2‐methylbutyl phosphate protecting group and enzymatically labile 3′‐O‐pivaloyloxymethyl group was followed at pH 7.5 and 37 °C by HPLC from the fully protected dimeric adenosine‐2′,5′‐monophosphate 1 used as a model compound for 2‐5A. The desired unprotected 2′,3′‐O‐isopropylideneadenosine‐2′,5′‐monophosphate ( 9 ) was observed to accumulate as a major product. Neither the competitive isomerization of 2′,5′‐ to a 3′,5′‐linkage nor the P–O5′ bond cleavage was detected. The phosphate protecting group was removed faster than the 3′‐O‐protection and, hence, the attack of the neighbouring 3′‐OH on phosphotriester moiety did not take place. 相似文献