510-13-4Relevant academic research and scientific papers
Computational and experimental analyses converge to reveal a coherent yet malleable aptamer structure that controls chemical reactivity
Tianjiao, Wang,Hoy, Julie A.,Lamm, Monica H.,Nilsen-Hamilton, Marit
, p. 14747 - 14755 (2009)
As short nucleic acids, aptamers in solution are believed to be structurally flexible. Consistent with this view, most aptamers examined for this property have been shown to bind their target molecules by mechanisms that can be described as "induced fit".
Kinetics of malachite green fading in water-ethanol-1-propanol ternary mixtures
Samiey, Babak,Zafari, Mahshid
, p. 32 - 39 (2012)
The rate constant of malachite green (MG+) alkaline fading was measured in water-ethanol-1-propanol ternary mixtures. This reaction was studied under pseudo-first-order conditions at 283-303 K. It was observed that the reaction rate constant increases in the presence of different weight percentages of ethanol and 1-propanol. The fundamental rate constants of MG+ fading in these solutions were obtained by SESMORTAC model. In each series of experiments, concentration of one alcohol was kept constant and the concentration of the second one was changed. It was observed that at constant concentration of one alcohol and variable concentrations of the second one, with increase in temperature, k1 values increase and this indicates that presence of ethanol (or 1-propanol) increases dissolution of 1-propanol (or ethanol) in the activated complex formed in these solutions. Also, in each zone, fundamental rate constants of reaction at each certain temperature change as k2 * k1 * k-1.
Kinetic exploration supplemented by spectroscopic and molecular docking analysis in search of the optimal conditions for effective degradation of malachite green
Dasmandal, Somnath,Mandal, Harasit Kumar,Rudra, Suparna,Kundu, Arjama,Majumdar, Tapas,Mahapatra, Ambikesh
, p. 38503 - 38512 (2015)
The degradation of malachite green (MG) by an alkaline hydrolytic process has been explored spectrophotometrically. The kinetics of the reaction have been meticulously studied under the influence of cationic alkyltrimethylammonium bromide (DTAB, TTAB and CTAB) surfactants, α-, β- and γ-cyclodextrins (CDs) and surfactant-β-CD mixed systems applying pseudo-first order conditions at 298 K. The surfactants and cyclodextrins individually catalyze the hydrolytic rate, whereas surfactant-β-CD mixed systems exhibit both an inhibiting and catalytic influence depending on the surfactant concentrations. The kinetic results have been explained precisely based on the pseudo-phase ion exchange (PIE) model of micelles and CD-catalyzed model of CD systems. The surfactants exhibit micellar surface catalysis, while CDs accelerate the rate by forming MG-CD inclusion complexes, thereby facilitating nucleophilic attack of its ionized secondary hydroxyl group on the carbocation center of MG. The encapsulation of MG within the supramolecular host cavity of the CDs has been investigated diligently using a steady-state absorption spectroscopic technique. The result shows 1:1 host-guest complexation with different relative orientations of the guest (MG) inside the hosts. Studies employing density functional theory (DFT) as well as molecular docking analysis provide valuable insight on the insertion mechanism. The results reveal that quantitative analysis can be utilized to predict the optimum conditions for the fastest degradation of MG in ambient environments.
Kinetics of malachite green fading in alcohol-water binary mixtures
Samiey, Babak,Toosi, Ali Raoof
, p. 508 - 518 (2010)
The rate constant of alkaline fading of malachite green (MG+) was studied in alcohol-water binary mixtures. This reaction was studied under pseudo-first-order conditions at 283-303 K. It was observed that the reaction rate constants were increased in the presence of different weight percentages of methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol, 1,2-propanediol, and glycerol (up to 19.3%). In aqueous glycerol solutions higher than 19.3%, the rate constant of reaction slightly decreases, which is due to high viscosity values of solvent mixtures. The fundamental rate constants of MG+ fading in these solutions were obtained by using the SESMORTAC model. Owing to the charged character of activated complex, with an increase in the weight percentage of the used cosolvents or temperature, κ2 values change according to the trend of hydroxide ion nucleophilic parameter values. Also, using MG+ solvatochromism, a simple test, called MAGUS, is introduced for measuring the glycerol concentration in its aqueous solutions.
Study of malachite green fading in water-ethanol-ethylene glycol ternary mixtures
Samiey, Babak,Ahmadi, Somayeh
, p. 151 - 164 (2013)
The rate constant of malachite green (MG+) alkaline fading was measured in water-ethanol-ethylene glycol ternary mixtures. This reaction was studied under pseudo-first-order conditions at 283-303 K. In each series of experiments, the concentration of ethanol was kept constant and the concentration of ethylene glycol was changed. It was shown that due to hydrogen bonding and hydrophobic interaction between MG+ and alcohol molecules the observed reaction rate constant, kobs, increased in the water-ethanol-ethylene glycol ternary mixtures. The fundamental rate constants of MG+ fading in these solutions (k1, k- 1 and k2) were obtained by the SESMORTAC model. Analysis of k1 and k2 values in solutions containing constant ethanol concentrations show that in low concentrations of ethylene glycol, hydrogen bonding formed between ethanol and ethylene glycol molecules and in high concentrations of ethylene glycol, ethanol as a solvent for ethylene glycol affected the reaction rate.
Kinetic investigations on alkaline fading of malachite green in the presence of micelles and reverse micelles
Dasmandal, Somnath,Mandal, Harasit Kumar,Kundu, Arjama,Mahapatra, Ambikesh
, p. 123 - 131 (2014)
The kinetics of alkaline hydrolysis of malachite green (MG+) have been studied spectrophotometrically in the presence of cetyltrimethylammonium bromide (CTAB) under pseudo-first-order condition at buffered of pH 11 and 298 K. The rate increases slightly up to the critical micelle concentration of CTAB then increases rapidly for surface catalysis of the micelles. The reaction has also been studied in the water pools of the CTAB/1-butanol/heptane/water reverse micelles and found 4-8 times faster over its rate in aqueous phase but the rate decreases exponentially with its water pool (w) size. The CTAB micellar medium has been characterized using steady state emission spectroscopy and tensiometry at the reaction condition for better explanation of the experimental findings. The thermodynamic activation parameters for the hydrolysis reaction have also been determined for comparison of the kinetic behavior in different environments.
Synthesis method of malachite green salt
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Paragraph 0045-0048; 0056-0063, (2019/12/25)
The invention relates to a synthesis method of malachite green salt. The method completely abandons traditional synthesis methods in the prior art, and tries to adopt a brand new synthesis route. A Grignard reagent is prepared, and a nucleophilic addition is carried out to synthesize leucomalachite green, and it is accidentally found that the method has the advantages of very few byproducts, and very high yield of the product; the malachite green salt prepared from the synthesized leucomalachite contains few impurities, and can be used as a high-quality candidate for a malachite green standardsubstance; and compared with the traditional synthesis methods, the method of the invention has the advantages of mild reaction conditions, and simplicity in operation.
Kinetics of fading of some triphenylmethane dyes: Effects of electric charge, substituent, and aqueous binary mixtures of dimethyl sulfoxide and 2-propanol
Samiey,Dalvand
, p. 60 - 70 (2014/01/06)
The rate constants of alkaline fading of a number of triphenylmethane (TPM) dyes including methyl green (ME2+), brilliant green (BG +), fuchsin acid (FA2-), and bromophenol blue (BPB 2-) were obtained in aqueous binary mixtures of 2-propanol (protic solvent) and dimethyl sulfoxide (DMSO) (aprotic solvent) at different temperatures. It was observed that the reaction rate constants of BG+ and ME2+ increased and those of FA2- and BPB2- decreased with an increase in weight percentages of aqueous 2-propanol and DMSO binary mixtures. 2-Propanol and DMSO interact with the used TPM molecules through hydrogen bonding and ion-dipole interaction, respectively, in addition to their hydrophobic interaction with TPM dyes. The fundamental rate constants of a fading reaction in these solutions were obtained by the SESMORTAC model. Also, the effect of electric charge and substituent groups of a number of TPM dyes on their alkaline fading rate was studied.
Stabilities of trityl-protected substrates: The wide mechanistic spectrum of trityl ester hydrolyses
Horn, Markus,Mayr, Herbert
supporting information; experimental part, p. 7469 - 7477 (2010/09/11)
Ionization rates of para-substituted triphenylmethyl (trityl) acetates, benzoates, and para-nitrobenzoates have been determined in aqueous acetonitrile and aqueous acetone at 25 °C. Conventional and stoppedflow techniques have been used to evaluate rate constants ranging from 1.38 × 10-5 to 2.15 × 102S-1 by conductimetry and photospectrometry methods. The varying stabilities of the differently substituted tritylium ions account for a gradual change of reaction mechanism. Poorly stabilized carbocations are generated slowly by the ionization of their covalent precursors and trapped fast by water. Better stabilized carbocations are generated more rapidly and accumulate, so that ionization and trapping by water can be observed as separate steps in a single experiment. Finally, highly stabilized tritylium ions do not react with water, and only the rates of their formation could be measured. The ionization rate constants correlate linearly with Winstein's ionizing powers Y; the low slopes (0.17 + parameters is excellent for symmetrically substituted tritylium derivatives, deviations for unsymmetrically substituted systems are observed. The failing rate-equilibrium relationship between the rates of ionizations (log kion) and the stabilities of the carbocations in aqueous solution (pKR+) may be explained by the late " development of resonance between a p-amino group and the carbocationic center of the tritylium ion during the ionization process.
The optical properties of triphenylmethane dye molecules and chromogens
Mikheev,Guseva,Ershov
body text, p. 1580 - 1588 (2009/02/04)
Industrial dye monomers, including malachite green, crystal violet, brilliant green, and methyl violet, were isolated by extraction with the use of heptane. UV light absorption bands characteristic of pure molecules were determined. The molecules of the dyes studied, which were ion pairs (formed by dye cations and oxalate or chlorine anions), did not absorb light in the visible range; that is, they were not chromogens. The conclusion was drawn that chromogen particles responsible for chromaticity were supramolecular dimers of nonchromogenic triphenylmethane series molecules. This conclusion was substantiated by trends in spectral transformations with the participation of immonium hydroxides obtained from dyes and side products of the synthesis of industrial dyes with quinoid molecular structures.
