Mixture Of CHCl3 Research Articles

On the excitation dependence of fluorescence spectra of meso-tetrapyridyl zinc (II) porphyrin and its relation with hydrogen bonding and outlying decoration.

Zinc porphyrins are potential candidates for boosting the advancement of various technological applications, including those exploring the molecule's radiative emissions. In this work, the excitation dependence of fluorescence spectra from 5,10,15,20-meso-tetrapyridyl zinc(II) porphyrin dissolved in a binary solvent mixture of CHCl3: MeOH, is reported. Important modifications in the profiles of the fluorescence bands are observed after exciting the molecules in a broad wavelength range from 350 to 565 nm. We attribute such modifications to the existence of two distinct relaxation pathways, related to two quasi-degenerated potential energy surfaces (PES) in the ZnTPyP's first excited state whose population rates changes for different excitation wavelengths. We also observed that by changing the CHCl3:MeOH proportion in the binary mixture, a quenching mechanism mediated by the MeOH hydrogen bondings and ZnTPyP takes place, which allows for tuning the excitation dependence of the aforementioned relaxations pathways. Moreover, our data confirm that the addition of outlying RuCl(dppb)(bipy) ruthenium complex linked to the pyridyl moieties of the ZnTPyP ring is also an excellent strategy to modify the excitation dependence of the fluorescence relaxation pathways.

Determination of Theobromine and Caffeine in Theobroma cacao Husk from Ethanolic Extract by GC-MS after CC Separation

After CC separation of 21 samples from Theobroma cacao Husk was analyzed by GC-MS, from ethanolic extract at 90% was recovered a solid residue of 1 g after several days on the table of the Lab. This main residue (300 mg) was analyzed after successive separations with mixtures of CHCl3: MeOH (7:3) and CHCl3: MeOH (5:5) in CC using Silica Gel G 60-120 Mesh. All samples were analyzed by TLC on silica gel with fluorescent indicator 254 nm on aluminum cards (layer thickness 0.2 mm) (10 × 20 cm) using CHCl3: MeOH: n-propanol: water (5:6:1:4) as eluent (v/v/v). The presence of Caffeine (CF) and Theobromine (TB) was confirmed after several analyses of the samples by their characteristic fragmentation pattern but nevertheless was found the presence of Theophylline.

Chromolaena tacotana (Klatt) R.M. King & H. Rob. Source of Flavonoids with Antiproliferative and Antioxidant Activity

Objective: To determine the antioxidant and antiproferative activity of the flavonoids isolated from the leaves of Chromolaena tacotana. Methods: Extraction was carried out with dichloromethane (CH2 Cl2 ) from the leaves by soxhlet, the flavonoids were isolated by column chromatography (Si gel G 60-200 microns 4 x 60cm) eluted with CHCl3 , mixtures of CHCl3 : MeOH and MeOH. The molecular structures were elucidated by 1 HNMR, 13CNMR mono and 2D and UV spectroscopic methods with displacement reagents. Each flavonoid was evaluated for its antioxidant activity by the methods DPPH● and ABTS● + and the cytotoxic activity was evaluated by MTT analysis. Findings: These compounds were identified as 3,5,4’-trihydroxy-7- methoxyflavone (Ct1), 3,5,8-trihydroxy-7,4’dimethoxyflavone (Ct2), 5,4’-dihydroxy-7-methoxyflavanonol (Ct3) and 5, 7, 3’, 4’-tetrahydroxy-3-methoxyflavone (Ct4). The flavonoid that had the best response in antioxidant activity was Ct4 with and IC50 of 2.51mg/L of DPPH● and 2.13 mg/L of ABTS●+ . Antiproliferative potential showed that MDA-MB-231 breast cancer cells were the most sensitivity cell line to the flavonoids, and Ct2 is the flavonoid with better antineoplastic potential on majority of cells, except for the most resistant SiHa cervix cancer cells. Application: The high antioxidant activity of flavonoids isolated from Chromolaena tacotana and its antiproliferative activity on different cell lines, make the species a plant with pharmacological potential. Keywords: Chromolaena tacotana. Flavonoids, Antioxidant Activity, Anticancer potential

Role of Hydrogen Bond in the Solvation Behavior of the Binary Mixtures Containing Fluorocarbon Alcohol Molecules and Chloroform: An Experimental and Theoretical Study

AbstractFluorocarbon containing alcohol molecules are important due to their unusual but important physicochemical properties. We have investigated solvatochromic as well as hydrogen bond behavior of weakly interacting binary mixtures of chloroform (CHCl3) with the fluorocarbon containing alcohols namely, 2‐fluoroethanol (MFE) and 2,2,2‐trifluoroethanol (TFE) as well as compared them with ethanol (ETH)‐CHCl3 binary mixture. UV‐Vis study depicts that the particular composition (χETH ∼0.6) of the binary mixtures of CHCl3 with ETH and MFE solvate probes more efficiently as compared to the respective counterparts, whereas, the probes are preferably solvated by the TFE as compared to solvent mixtures in the case of TFE‐CHCl3 binary mixture. NMR, IR as well as theoretical calculations establish that CHCl3 forms the C−H…O hydrogen bonded clusters with ETH and MFE whereas TFE‐CHCl3 binary mixture are connected predominantly through C−H…F hydrogen bond. The dipole of probe molecules perturbs the weaker C−H…F hydrogen bond present in the TFE‐CHCl3 binary mixture resulting in the preferential solvation by the TFE, whereas, the comparatively stronger C−H…O hydrogen bonded species is preserved in the binary mixtures of CHCl3 with ETH and MFE which leads to the favorable solvation by the binary mixtures of CHCl3 with ETH and MFE. Further, analytical solvent exchange models have been used to substantiate the solvation behavior of the probe molecules in the CHCl3 binary mixtures with ETH and TFE.

ChemInform Abstract: Synthesis and Properties of Nanocrystalline π‐SnS — A New Cubic Phase of Tin Sulfide.

AbstractCubic π‐SnS nanoparticles are precipitated by melting tin ethylxanthate as precursor and octadecylamine (120 °C, 30 min) after which (Tms)2NH is added under further heating to 220 °C (2 h) before being transferred to a 1:1 mixture of CHCl3 and MeOH.

Growth, Fatty Acid, and Lipid Composition of Marine MicroalgaeSkeletonema costatumAvailable in Bangladesh Coast: Consideration as Biodiesel Feedstock

Among the various potential sources of renewable energy, biofuels are of most interest. Marine microalgae are the most promising oil sources for making biofuels, which can grow very rapidly and convert solar energy to chemical energy via CO2fixation. The fatty acid profile of almost all the microalgal oil is suitable for the synthesis of biofuel. In this research, fatty acid and lipid contents of Bangladeshi strains of marine microalgaeSkeletonema costatumwere performed. For this, the crude oil was extracted by Soxhlet extraction method, using three most common solvent systems, pure hexane and mixture of CHCl3 : MeOH (2 : 1) and hexane : EtOH (3 : 1) one by one. Highest oil recovery (15.37%) came from CHCl3 : MeOH (2 : 1) solvent system from dry biomass whereas the lowest (2.49%) came from n-hexane from wet biomass. The qualitative analysis of the extracted oil by GC/MS analysis revealed that it contained significant amount of myristic acid (C14:0), palmitic acid (C16:0), stearic acid (C18:0), and palmitoleic acid (C16:1). It also indicated presence of hexadecatrienoic acid, benzenedicarboxylic acid, oleic acid, arachidonic acid, eicosapentaenoic acid (EPA), 9-Octadecenoic acid methyl ester (C19H36O2), and so forth. The obtained fatty acid profile indicates high potentiality ofS. costatumspecies to be used as promising biofuel feedstock a little improvisation and substantially it can replace diesel in near future.

Quality standard study on Pteris multifida

The quality control method and standard were established to control the quality of Pteris multifida in this paper. The tests of water content, total ash, acid-unsoluble ash and ethanol-soluble extractives of P. multifida were carried out according to the methods recorded in appendix of Chinese Pharmacopeia (2010 edition, volume 1) . The TLC method was established by using rhoifolin as references, and a mixture of CHCl3 -MeOH-HAc (6: 1: 1) as the developing solvent system on GF254 thin layer plate. The contents of rhoifolin was determined by HPLC on a Diamonsil C18 (4.6 mm x 250 mm, 5 μm) column, using acetonitrile-water (containing 0.15% formic acid) (16: 84) as mobile phase at a flow rate of 1.0 mL x min(-1). The column temperature was 30 degrees C and the detection wave-length was 350 nm. As a result, pterosin C 3-O-β-D-glucosidede and the other constituents were well separated on TLC detected under the UV light at 254 nm . The methodology validation for the assay of rhoifolin presented that it was in good linear correlation in the ranges of 0.025 5-5.1 μg with the regression equations of Y = 1 092.4X + 9.503 5 (r = 0.999 8), and the average recoveries were 100.3% (RSD 1.3%). The content range of rhoifolin from 16 different batches of Pteris multifida was 0.08-5.06 mg x g(-1). The water content, total ash, acid-unsoluble ash and ethanol-soluble extractives of 16 samples varied in the ranges of 7.35% - 12.96%, 6.90% - 16.33%, 2.07% -11.38% and 13.29% -23.87%, respectively. The suggesting limes in the quality standard for water content, total ash, acid-unsoluble ash, ethanol-soluble extractives and rhoifolin content were ≤ 12% , ≤ 15% , ≤ 8.5% , ≥ 14% and ≥ 0.040%, respectively. The result proved that the established quality of control method was specific and accurate, which can be used for the quality control of P. multifida.

Rapid extraction, isolation, and quantification of oleanolic acid fromLantana camaraL. Roots using microwave and HPLC-PDA techniques

Summary An ecofriendly solvent polarity based microwave-assisted extraction (MAE) technique was developed for the rapid extraction and isolation of bioactive oleanolic acid from roots of Lantana camara L. Several different influential extraction parameters such as microwave power, extraction time, solvent type, and volume were studied in a systematic fashion for the determination of optimum extraction conditions. Simply modified and rapid high-performance liquid chromatography-diode array detector (HPLC-DAD) method was also developed and validated for quantitative determination of oleanolic acid from roots of L. camara. Under optimum conditions, using a mixture of CHCl3:MeOH (60:40, v/v, 15 mL) as a solvent, 600 W microwave powers, and 50 °C temperature for 6 min of MAE produced a maximum yield of 1.23% (dry weight of roots). No degradation of the target analyte was observed at the optimum conditions as evidenced from the recovery studies performed with standard oleanolic acid. The proposed method also showed high degree of reproducibility; hence, it may be useful for maximum extraction and isolation of biologically active oleanolic acid.

2]pseudorotaxanes derived from 27‐ and 29‐membered oxaazacyclophanes and 1,2‐bis(benzimidazolium)ethane salts

Four novel 27‐ and 29‐membered oxaazacyclophanes were synthetized via the high dilution method in moderate to good yields, employing aromatic dialdehydes and diamines as precursors to generate first the corresponding cyclic Schiff bases, which were then reduced in almost quantitatively yields to the corresponding macrocyclic diamines. All compounds were characterized by conventional techniques such as IR and NMR (1H, 13C) spectroscopy, elemental analysis, and mass spectrometry. Besides, two macrocycles were studied by single‐crystal X‐ray diffraction analysis, which revealed that their cavities are appropriate to include small molecules. Using two representative oxaazacyclophanes (OX‐3 and OX‐4) as wheels and 1,2‐bis(benzimidazolium)ethane salts as axles, [2]pseudorotaxanes were formed in 1:1 (v/v) solvent mixtures of CHCl3 and MeCN and studied by 1H NMR and ultraviolet/visible (UV/Vis) spectroscopy, and electrospray ionization‐time‐of‐flight mass spectrometry, finding in all cases the formation of stable 1:1 complexes. The binding constants of the complexes were determined by UV/Vis and 1H NMR titration experiments, giving values ranging from 0.52 × 103 to 4.6 × 103 M−1. Likely, complex structures were investigated in the gas‐phase using density functional theory calculations at the B3LYP/6‐31G(d) level of theory. The complexation experiments together with the results from the molecular modeling studies indicate that dicationic axles can penetrate the cavity of the oxaazacyclophanes synthesized herein to give a new family of [2]pseudorotaxanes. These supramolecular structures are held together by π−π stacking interactions (charge‐transfer), charge‐assisted hydrogen bonds, and ion dipole forces. Copyright © 2012 John Wiley & Sons, Ltd.

Two-Dimensional Melting and Phase Change of Binary Mixtures of CCl4 and CHCl3 Confined in ACF Nanospace Studied Using Solid-State 1H NMR

Abstract Two-dimensional melting and phase changes of binary mixtures of CCl4 and CHCl3 confined in activated carbon fiber were examined using differential thermal analysis and 1H wide-line NMR. Molecular assembly of CCl4 confined in ACF nanospace with a slit width of 1.1 nm showed succeeding thermal anomalies corresponding to crystal–hexatic and hexatic–liquid transitions. Results showed that these thermal anomalies did not occur in a mixture of CHCl3 and CCl4. This behavior differed greatly from the phase diagram for the bulk mixture between CHCl3 and CCl4. Furthermore, the dynamic features of CHCl3 molecule were examined using the 1H wide-line NMR spectrum. The activation energy of the hopping motion changed from 7 kJ mol−1 for pure CHCl3 to 13 kJ mol−1 for CHCl3 with a 0.016 molar ratio in CCl4. In particular, a drastic increase in the activation energy was observed for doping with a trace amount of CHCl3, suggesting that molecular self-assembly of CCl4 takes place in the ACF nanoslit because of the effective intermolecular interaction between CCl4 molecules. The existence of CHCl3 in CCl4 brings about the remarkable impurity effect on two-dimensional melting and phase transition of CCl4 confined in ACF nanospace.

Extraction and Analysis of Auxins in Plants Using Dispersive Liquid−Liquid Microextraction Followed by High-Performance Liquid Chromatography with Fluorescence Detection

Auxin plays an important role in cell differentiation, apical dominance, and tropism in plants. A new method based on dispersive liquid-liquid microextraction (DLLME) combined with high-performance liquid chromatography-fluorescence detection (HPLC-FLD) has been established to detect auxin. A mixture of CHCl(3) (extraction solvent) and acetone (disperser solvent) was injected quickly into a sample solution with desired salt concentration and pH value, and then a cloudy solution consisting of many dispersed fine droplets of CHCl(3) was formed. After centrifugation, the sedimented phase was withdrawn and directly analyzed by HPLC-FLD. Under optimal conditions, four auxins were baseline separated within 3.5 min, with the minimal limit of detection of 0.02 ng mL(-1) and coefficient correlations in the range of 0.9980-0.9995. This simple method was successfully applied to real sample analysis. Experimental results showed that DLLME was a high-performance and powerful preconcentration method to extract and enrich related plant auxin.

Identification of phosphatidylserylglutamate: a novel minor lipid in Escherichia coli

Advances in mass spectrometry have facilitated the identification of novel lipid structures. In this work, we fractionated the lipids of Escherichia coli B and analyzed the fractions using negative-ion electrospray ionization mass spectrometry to reveal unknown lipid structures. Analysis of a fraction eluting with high salt from DEAE cellulose revealed a series of ions not corresponding to any of the known lipids of E. coli. The ions, with m/z 861.5, 875.5, 887.5, 889.5, and 915.5, were analyzed using collision-induced dissociation mass spectrometry (MS/MS) and yielded related fragmentation patterns consistent with a novel diacylated glycerophospholipid. Product ions arising by neutral loss of 216 mass units were observed with all of the unknowns. A corresponding negative product ion was also observed at m/z 215.0. Additional ions at m/z 197.0, 171.0, 146.0, and 128.0 were used to propose the novel structure phosphatidylserylglutamate (PSE). The hypothesized structure was confirmed by comparison with the MS/MS spectrum of a synthetic standard. Normal phase liquid chromatography-mass spectrometry analysis further showed that the endogenous PSE and synthetic PSE eluted with the same retention times. PSE was also observed in the equivalent anion exchange fractions of total lipids extracted from the wild-type E. coli K-12 strain MG1655.

A new cadinane sesquiterpene from the marine brown alga Dictyopteris divaricata.

A sample of the marine brown alga D. divaricata collected off the coast of Yantai (P.R. China) was dried, powdered, and extracted with the mixture of CHCl3 and MeOH (1:1, v/v). By a combination of silica gel and Sephadex LH-20 column chromatography and preparative TLC, a new cadinane sesquiterpene 1,4-epoxymuurolan-5β-ol (1) was isolated from this species. Its structure was established by detailed MS and NMR spectroscopic analysis, as well as comparison with literature data.

Tripeptides: Efficient Catalysts for 1,4-Addition Reactions to Nitroolefins

The authors designed tripeptide 1 as an efficient organocatalyst for the asymmetric conjugate addition reactions between aldehydes and nitroolefins. The authors have used N-methyl morpholine (NMM) as an additive for this reaction. After screening different solvents, a mixture of CHCl3 and i-PrOH (9:1) has been found to be the best solvent for this reaction. With 1-5 mol% of catalyst 1, good to high diastereoselectivities (dr = 4:1 to >99:1) and excellent enantioselectivities (er = 91:9 to >99:1) were obtained for different aldehydes and nitroolefins.

Device for Raman Difference Spectroscopy

A new layout of a versatile Raman difference setup is presented. The new device combines the advantages of the rotating cell for exploitation of the resonance Raman enhancement and the high precision of Raman difference spectroscopy together with the multiplex advantages and very high quantum efficiency offered by a CCD detector. While Raman difference spectroscopy is the most accurate method for the detection of very small band shifts, the method requires the strict prevention of any environmental perturbation of one of the two spectra, which are used for the difference spectra calculation. The presented device satisfies this requirement by implementing a double-beam layout, where the simultaneously detected Raman signals of two sample cells are combined within a Y-fiber bundle and imaged together onto the CCD detector. The accuracy of the new apparatus in detecting frequency shifts and minor sample components is greatly increased compared to conventional Raman spectroscopy as shown by studying binary mixtures of CHCl3 and CCl4. Hereby it was possible to resolve a formerly undetected shift of <0.02 cm(-1) of the CCl4 band at 218 cm(-1). The new RDS setup has a very versatile design. The device can take advantage of the high sensitivity and selectivity of the resonance Raman enhancement applying excitation wavelengths from the UV to NIR and can be used for a variety of samples with only minor changes in the optical arrangement. The new device will be of utmost importance for a fast, gentle, sensitive, selective, and precise investigation of biomolecules and their interactions. Some first results are shown concerning the interaction of the antimalarial chloroquine with hematin in a hydrous environment.

Convergent Solid-phase Peptide Synthesis Performed in a CHCl3-phenol Mixed Solvent: Synthesis of Amyloid β-peptides as Examples with a Difficult Sequence

Convergent solid-phase peptide synthesis (CSPPS) involving the coupling of protected peptide segments on a solid support performed in a β-sheet disrupting solvent consisting of a mixture of CHCl3 and phenol (v/v, 3/1), proceeded smoothly without danger of epimerization or of significant phenyl ester formation with the carboxyl component when diisopropylcarbodiimide (DIC) was used in the presence of 1-hydroxy-7-azabenzotriazole (HOAt) or 6-chloro-1-hydroxybenzotriazole (Cl-HOBt). In particular, this synthetic strategy using the CHCl3 and phenol mixed solvent proved to be essential for coupling sparingly soluble segments even with difficult sequences. The present approach was successfully applied to the synthesis of amyloid β-peptide (Aβ) (1-40) and also its reversed Aβ (40-1) as an inactive control peptide.

Dose‐Dependent Liver Tissue Repair After Chloroform plus Trichloroethylene Binary Mixture

Abstract: The aim of the present study was to investigate the hypothesis that liver tissue repair induced by exposure to chloroform (CHCl3)+trichloroethylene binary mixture (BM) is dose‐dependent similar to that elicited by exposure to these compounds individually. Male Sprague‐Dawley rats (250–300 g) received three dose combinations of binary mixture (74+250, 185+500 and 370+1250 mg CHCl3+trichloroethylene/kg, intraperitoneally) in corn oil (maximum of 0.5 ml/kg). Liver injury was assessed by plasma alanine amino transaminase (ALT) activity and histopathology by haematoxylin &amp; eosin. Liver tissue repair was measured by 3H‐thymidine incorporation into hepatonuclear DNA. Blood and liver levels of both the parent compounds and two major metabolites of trichloroethylene (trichloroacetic acid and trichloroethanol) were quantified by gas chromatography. The blood and liver CHCl3 levels after the administration of binary mixture were similar compared to the administration of CHCl3 alone. The blood and liver trichloroethylene levels after the binary mixture were significantly lower compared to trichloroethylene alone due to higher elimination in presence of CHCl3, resulting in decreased production of metabolites. The antagonistic toxicokinetics resulted in lower liver injury than the summation of injury caused by the individual components at all three dose levels. On the other hand, tissue repair elicited by the binary mixture was dose‐dependent. The interactive toxicity of this binary mixture of CHCl3 and trichloroethylene led to subadditive initial liver injury because of a combined effect of higher elimination of TCE and mitigated progression of liver injury was prevented by timely dose‐dependent stimulation of compensatory tissue repair. Even though the doses of the toxicants employed in this study are much higher than found in the environment, the results suggest that a mixture of these two compounds at environmental levels is unlikely to cause any exaggerated interactive acute liver toxicity of any biological significance.

Self-assembly and stability of double rosette nanostructures with biological functionalities

The syntheses of calix[4]arene dimelamines that are functionalized with alkyl, aminoalkyl, ureido, pyridyl, carbohydrate, amino acid and peptide functionalities, and their self-assembly with barbituric acid or cyanuric acid derivatives into well-defined hydrogen-bonded nanostructures are described. The thermodynamic stability of these hydrogen-bonded assemblies was studied by CD spectroscopy in mixtures of CHCl3 and MeOH. The stability of the assemblies depends on several steric factors and the polarity of the functional groups connected to the assembly components.

Cation-reinforced donor-acceptor pseudorotaxanes

Formation of a series of pseudorotaxanes from an electron-rich crown ether (host 1), pyromellitic diimide (guest 2) and alkali salt templates MX, where M = Li+ and Na+, and X− = Br−, I−, CF3SO3−, [B(C6F5)4]− and [B{3,5-(CF3)2(C6H3)}4]−, is reported. Mixing of 1 and 2 in CH2Cl2 or a mixture of CHCl3 and MeOH (98∶2) gave a pale yellow solution indicative of a very weak charge-transfer interaction. Upon addition of MX, brightly coloured solutions were obtained, resulting from a red shift and an increase in the intensity of the charge-transfer band. Structural and kinetic studies of the pseudorotaxanes were performed by NMR. The solution-phase structures of [M2·1·2]2+ are in good agreement with the solid-phase structure determined by X-ray crystallography. The remarkable templating properties of Li+ for the 1·2 donor-acceptor complex are due to the almost perfect coincidence of coordinative geometries in [Li2·1]2+ and [Li2·1·2]2+.

Self-Assembling Properties of a Membrane-Modifying Lipopeptaibol in Weakly Polar Solvents Studied by CW ESR

The self-assembling properties of TOAC spin-labeled analogues of the lipopeptaibol antibiotic trichogin GA IV have been studied by CW ESR in solvents of different polarity, ranging from CHCl3 to a mixture of CHCl3−toluene and CCl4 at different concentrations. At room temperature, evidence has been obtained that, in all of the solvents examined, a supramolecular assembly exists which is in equilibrium with monomeric molecules. The ESR spectral lines of the aggregates of double-labeled peptides are wider than those obtained from single-labeled peptides. Line widths were used to assess the rotational mobility of both the aggregates and the monomers. Their hydrodynamic radii were estimated to determine the number of peptide molecules per aggregate. This value (close to 4) almost coincides with the previously reported value for spin-labeled peptide clusters in frozen glassy solutions. Spectral broadenings, due to the modulation of the intra- and intermolecular dipole−dipole interactions of spin labels by the rotational mobility of aggregates, were separated by analyzing the ESR solution spectra of spin-labeled and nonlabeled peptide mixtures. The intramolecular distance between spin labels of the double-labeled peptide in the aggregate was estimated to be 10.1 Å, which most closely corresponded to the α-helical conformation. It has been further established that the broadening due to the intermolecular coupling of spin labels is substantially greater in aggregates formed by a mixture of peptides labeled at different positions than it is in aggregates made only of one kind of single-labeled peptide. The intermolecular distances between labels were estimated to be about 9.2 and 16 Å in the two cases, respectively. The results agree with a helix bundle where the helices are oriented in an antiparallel fashion.