779-27-1Relevant articles and documents
Chemical enhancement by nanomaterials under X-ray irradiation
Cheng, Neal N.,Starkewolf, Zane,Davidson, R. Andrew,Sharmah, Arjun,Lee, Changju,Lien, Jennifer,Guo, Ting
, p. 1950 - 1953 (2012)
We report here a new phenomenon of dynamic enhancement of chemical reactions by nanomaterials under hard X-ray irradiation. The nanomaterials were gold and platinum nanoparticles, and the chemical reaction employed was the hydroxylation of coumarin carboxylic acid. The reaction yield was enhanced 2000 times over that predicted on the basis of the absorption of X-rays only by the nanoparticles, and the enhancement was found for the first time to depend on the X-ray dose rate. The maximum turnover frequency was measured at 1 × 10-4 s-1 Gy-1. We call this process chemical enhancement, which is defined as the increased yield of a chemical reaction due to the chemical properties of the added materials. The chemical enhancement described here is believed to be ubiquitous and may significantly alter the outcome of chemical reactions under X-ray irradiation with the assistance of nanomaterials.
X-ray and solution structures of CuIIGHK and CuIIDAHK complexes: Influence on their redox properties
Hureau, Christelle,Eury, Helene,Guillot, Regis,Bijani, Christian,Sayen, Stephanie,Solari, Pier-Lorenzo,Guillon, Emmanuel,Faller, Peter,Dorlet, Pierre
, p. 10151 - 10160 (2011)
The Gly-His-Lys (GHK) peptide and the Asp-Ala-His-Lys (DAHK) sequences are naturally occurring high-affinity copper(II) chelators found in the blood plasma and are hence of biological interest. A structural study of the copper complexes of these peptides was conducted in the solid state and in solution by determining their X-ray structures, and by using a large range of spectroscopies, including EPR and HYSCORE (hyperfine sub-level correlation), X-ray absorption and 1H and 13C NMR spectroscopy. The results indicate that the structures of [CuII(DAHK)] in the solid state and in solution are similar and confirm the equatorial coordination sphere of NH2, two amidyl N and one imidazole N. Additionally, a water molecule is bound apically to CuII as revealed by the X-ray structure. As reported previously in the literature, [CuII(GHK)], which exhibits a dimeric structure in the solid state, forms a monomeric complex in solution with three nitrogen ligands: NH2, amidyl and imidazole. The fourth equatorial site is occupied by a labile oxygen atom from a carboxylate ligand in the solid state. We probe that fourth position and study ternary complexes of [CuII(GHK)] with glycine or histidine. The CuII exchange reaction between different DAHK peptides is very slow, in contrast to [CuII(GHK)], in which the fast exchange was attributed to the presence of a [CuII(GHK)2] complex. The redox properties of [CuII(GHK)] and [CuII(DAHK)] were investigated by cyclic voltammetry and by measuring the ascorbate oxidation in the presence of molecular oxygen. The measurements indicate that both Cu II complexes are inert under moderate redox potentials. In contrast to [CuII(DAHK)], [CuII(GHK)] could be reduced to Cu I around -0.62 V (versus AgCl/Ag) with subsequent release of the Cu ion. These complete analyses of structure and redox activity of those complexes gave new insights with biological impact and can serve as models for other more complicated CuII-peptide interactions. Copyright
The effect of potential supramolecular-bond promoters on the DNA-interacting abilities of copper-terpyridine compounds
Grau, Jordi,Brissos, Rosa F.,Salinas-Uber, Jorge,Caballero, Ana B.,Caubet, Amparo,Roubeau, Olivier,Korrodi-Gregório, Luís,Pérez-Tomás, Ricardo,Gamez, Patrick
, p. 16061 - 16072 (2015)
Three copper(ii) coordination compounds have been prepared from three different 2,2′:6′,2′′-terpyridine-based ligands, which have been selected to investigate the potential role of supramolecular interactions on the DNA-interacting and cytotoxicity properties of the corresponding metal complexes. Hence, the ligands 4′-((naphthalen-2-yl)methoxy)-2,2′:6′,2′′-terpyridine (Naphtpy) and 4′-((1H-benzo[d]imidazol-2-yl)methoxy)-2,2′:6′,2′′-terpyridine (Bimztpy) have been synthesized from commercially-available 4′-chloro-2,2′:6′,2′′-terpyridine (Cltpy), and their copper(ii) complexes have been obtained by reaction with copper(ii) nitrate. The DNA-interacting abilities of the corresponding compounds [Cu(Cltpy)(H2O)(NO3)2] (1), [Cu(naphtpy)(NO3)(H2O)](NO3)(MeOH) (2) and [Cu(bimztpy)(NO3)(H2O)](NO3) (3) have been investigated using different techniques, and cytotoxicity assays with several cancer cell lines have revealed interesting features, viz. the more efficient complex is 2, which although it does not act as a DNA cleaver, displays the most effective DNA-interacting and cytotoxic properties, compared to 1 and 3.
Unique pH-Sensitive RNA Binder for Ratiometric Visualization of Cell Apoptosis
Tian, Minggang,Sun, Jie,Dong, Baoli,Lin, Weiying
, p. 10056 - 10063 (2019)
Fluorescent probes for monitoring cell apoptosis are powerful tools in biological and pathological research. However, ratiometric probes for in situ and real-time visualization of apoptosis with high accuracy are still deficient, which limits the studies relative to cell apoptosis. In this work, a pH-sensitive and positively charged RNA binder was designed and synthesized for the first time for the ratiometric visualization of cell apoptosis. In healthy cells, the probe targets mitochondria with basic matrixes and high membrane potential and displays intense emission in the blue and red channels. During apoptosis, the probe is released from mitochondria, binds to basophilic RNA, and shows emission in only the red channel. Consequently, cell apoptosis caused by drug treatment could be efficiently and clearly monitored in a ratiometric manner. The probe is expected to facilitate the study of cell apoptosis and relative areas.
Distinguishable multi-substance detection based on three-channel NIR fluorescent probe in physiology and pathology of living cells and zebrafish
Li, Sha,Huo, Fangjun,Yue, Yongkang,Ma, Kaiqing,Wen, Ying,Yin, Caixia
, p. 3870 - 3875 (2021)
Mitochondria is the main organelle for the production of reactive sulfur species (RSS), such as homocysteine (Hcy), cysteine (Cys), glutathione (GSH) and sulfur dioxide (SO2). These compounds participate in a large number of physiological processes and play an extremely important role in maintaining the balance of life systems. Abnormal concentration and metabolism are closely related to many diseases. Due to their similarities in chemical properties, it is challenging to develop a single fluorescent probe to distinguish them simultaneously. Here, we synthesized the probe PI-CO[sbnd]NBD with three fluorophores, NBD-Cl and benzopyranate as the reaction sites of GSH/Cys/Hcy and SO2, respectively. Three biothiols all could cleavage ether bond to release benzopyrylium and coumarin moiety, which emitted red and blue fluorescence, but Cys/Hcy also could do intramolecular rearrangement after nucleophilic substitution, resulting in yellow fluorescence. Thus the probe can distinguish Cys/Hcy and GSH. Subsequently, only SO2 could quench red fluorescence by adding C[dbnd]C of benzopyrylium. The probe also could localize well in mitochondria by oxonium ion for all kinds of cells. The probe not only could detect above sulfur-containing active substances of intracellular and extracellular but also monitor the level of them under oxidative stress and apoptosis process in living cells and zebrafish.
Highly selective on-off fluorescence recognition of Fe3+ based on a coumarin derivative and its application in live-cell imaging
Warrier, Sona,Kharkar, Prashant S.
, p. 659 - 665 (2018)
A novel coumarin chemosensor, 7-hydroxy-2-oxo-N-(pyridin-2-ylmethyl)chromene-3-carboxamide (Probe 1), demonstrated significant selectivity towards Fe3+ ions. Probe 1 exhibited high fluorescence emission profile at 447?nm, excellent selectivity towards Fe3+ over other biologically important metal ions (Al3+, Ba2+, Co2+, Cu2+, Zn2+, Cd2+, Hg2+, Pb2+ and Sn2+). Interestingly, there was ~?30-fold decrease in fluorescence intensity upon Fe3+ binding. The limit of detection of Fe3+ was found to be 0.76?μM (~?40?ppb). Probe 1 also exhibited high potential as an intracellular chemosensor for Fe3+.
Method for synthesizing coumarin-3-carboxylic acid compounds by one-pot two-step method
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Paragraph 0053; 0056; 0058; 0077; 0079; 0084-0090, (2021/06/12)
The invention relates to a method for synthesizing coumarin-3-carboxylic acid compounds by a one-pot two-step method. The structural formula of the coumarin-3-carboxylic acid compounds is shown in the description, wherein R1 is H , Cl , Br, NO2 , CH3 and HO . According to the synthesis process of the coumarin-3-carboxylic acid compounds, malonic acid, acetone and substituted salicylaldehyde serve as raw materials, iodine serves as a catalyst, acetic anhydride serves as a solvent, a series of coumarin-3-carboxylic acid compounds are synthesized through a one-pot cascade reaction, and the efficiency and the yield are greatly improved compared with a fractional step method.
3-carboxylic acid and formyl-derived coumarins as photoinitiators in photo-oxidation or photo-reduction processes for photopolymerization upon visible light: Photocomposite synthesis and 3d printing applications
Dumur, Frédéric,Gigmes, Didier,Graff, Bernadette,Hamieh, Tayssir,Lalevée, Jacques,Noirbent, Guillaume,Rahal, Mahmoud,Toufaily, Joumana
, (2021/06/16)
In this paper, nine organic compounds based on the coumarin scaffold and different substituents were synthesized and used as high-performance photoinitiators for free radical pho-topolymerization (FRP) of meth(acrylate) functions under visible light irradiation using LED at 405 nm. In fact, these compounds showed a very high initiation capacity and very good polymerization profiles (both high rate of polymerization (Rp) and final conversion (FC)) using two and three-component photoinitiating systems based on coum/iodonium salt (0.1%/1% w/w) and coum/iodonium salt/amine (0.1%/1%/1% w/w/w), respectively. To demonstrate the efficiency of the initiation of photopolymerization, several techniques were used to study the photophysical and photochemical properties of coumarins, such as: UV-visible absorption spectroscopy, steady-state photolysis, real-time FTIR, and cyclic voltammetry. On the other hand, these compounds were also tested in direct laser write experiments (3D printing). The synthesis of photocomposites based on glass fiber or carbon fiber using an LED conveyor at 385 nm (0.7 W/cm2 ) was also examined.
