Solvent extraction of trivalent indium from succinate solution by 2-octylaminopyridine in chloroform

Extraction processes of indium(III) with 2-octylaminopyridine (2-OAP) from media of various complexing ability, succinate and salicylate, in chloroform have been elucidated. The ion-pair complex has also quantitative extraction in xylene and 1,2-dichloroethane. Indium(III) from organic phase was stripped with 1.0 M hydrochloric acid and determined complexometrically with EDTA. The stoichiometry of the extracted species was found out on the basis of slope analysis. The extraction of indium(III) proceeds by an anion exchange mechanism and the extracted species is [RR′NH₂ ⁺In(succinate)₂ ^-]_(org). Temperature dependence of the extraction equilibrium constant was also examined to estimate the apparent thermodynamic functions (ΔH, ΔG and ΔS) for extraction reaction. It is possible to separate indium(III) from Zn(II), Cd(II), Pb(II), Hg(II), Bi(III), Tl(I), Tl(III), Ga(III), Al(III), Te(IV), Se(IV), Sb(III), Fe(III) and Sn(IV). The method is simple, rapid and reproducible and can be used to determine the indium from samples like alloys.     

PTSA-catalyzed straightforward novel approach for the synthesis of 1,2-bis(4-nitrophenyl)-1H-benzo[f]chromen-3-amine and the evaluation of their antituberculosis activity

Research on Chemical Intermediates - A highly efficient protocol for the synthesis of 1,2-bis(4-nitrophenyl)-1H-benzo[f]chromen-3-amine derivative has been illustrated by a one-pot three-component...     

FRET Between Riboflavin and 9-Anthraldehyde Based Fluorescent Organic Nanoparticles Possessing Antibacterial Activity

The aqueous suspension of fluorescent nanoparticles were prepared by using 9-anthradehdye derivative (AH). The nanoparticles (AHNPs) were characterized using DLS-zeta sizer and SEM techniques. The photo physical properties of nanoparticles and precursor were measured and compared using UV-absorption spectroscopy, fluorescence spectroscopy and fluorescence lifetime studies. The significant overlap between fluorescence spectrum of AHNPs and excitation spectrum of Riboflavin (RF) led us to explore Fluorescence Resonance Energy Transfer (FRET) studies between AHNPs and RF in aqueous medium. The mechanism of FRET from AHNPs to RF discussed on spectral observations, thermodynamic parameters and changes produces in fluorescence lifetime in absence and presence of different concentrations of RF to AHNPs. The limit of detection for RF (0.071 µM) is considerably low compared with reported methods. Thus, we explore AHNPs as novel nano probe for quantitative determination of RF in pharmaceutical samples based on FRET study. In addition with this, AHNPs has excellent antibacterial activity than the bulk material for two different bacteria culture viz. E. coli and Bacillus sps.

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Graphical Abstract 9-anthradehdye based fluorescent nanoparticles (AHNPs) explores as nano probe to detect Riboflavin (RF) in aqueous medium based on Fluorescence Resonance Energy Transfer (FRET) studies. The proposed analytical method successfully applied for quantitative determination of RF in pharmaceutical samples. In addition, with this, AHNPs has excellent antibacterial activity than the bulk material for two different bacteria culture suspension viz. E. coli and Bacillus sps.

     

Demarcation of reaction effects on laminar burning velocities of diluted syngas–air mixtures at elevated temperatures

Laminar burning velocities of CO₂/N₂ (60%, 70%) diluted H₂/CO/air mixtures were measured at elevated temperatures using the externally heated diverging channel method. The computed burning velocities using the two reaction mechanisms (Davis et al., Proc. Combust. Inst. 2005;30(1):1283–1292; FFCM-1, http://nanoenergy.stanford.edu/ffcm1 ) are compared with the experimentally determined burning velocities. The accuracy of the chemical kinetic mechanisms at high dilution rates and elevated temperatures was investigated for various hydrogen fractions in the fuel composition. The burning velocity is observed to increase at high temperatures due to higher mixture enthalpy. The dilution effect on the variation of laminar burning velocity was stronger for the CO₂ dilution case compared to N₂ dilution. A comparison between the FFCM-1 mechanism and experimental measurements shows an accurate depiction of the reaction chemistry regarding the prediction of laminar burning velocities. The role of third-body reactions and direct inhibiting effect of N₂ and CO₂ molecules on burning velocity of diluted syngas–air mixtures is analyzed in detail. Detailed kinetic analysis revealed that the use of GRI 3.0 collision efficiency factors in the Davis mechanism helps in accurately predicting the burning velocities at elevated temperatures and high CO₂ dilution rates. The thermal effect dominates the reduction in laminar burning velocity for N₂ dilution case. The FFCM-1 mechanism agrees well with the experiments for syngas flames diluted with N₂ compared to the Davis mechanism. The addition of third-body efficiency of N₂ in the FFCM-1 mechanism improved the predictions of laminar burning velocities for the N₂ dilution case.     

Recognition of D-Penicillamine Using Schiff Base Centered Fluorescent Organic Nanoparticles and Application to Medicine Analysis

Schiff base centered fluorescent organic compound 1,1′-[(1E,2E)-hydrazine-1,2-diylidenedi(E)methylylidene]- dinaphthalen-2-ol (HN) was synthesized followed by spectral characterization viz., NMR, IR and Mass spectroscopy. The fluorescent nanoparticles of HN prepared using reprecipitation method shows red shifted aggregation induced enhanced emission (AIEE) with respect to HN solution in acetone. The average particle size of nanoparticles (HNNPs) is of 67.2 nm shows sphere shape morphology. The surfactant cetyltrimethyl ammonium bromide (CTAB) used to stabilize HNNPs induces positive charge surface with zeta potential of 11.6 mV. The positive charge of HNNPs responsible to adsorb oppositely charged analyte on its surface with binding interactions. The fluorescence experiments performed with and without addition of different analytes to the aqueous suspension of HNNPs shows selective fluorescence quenching of HNNPs by D-Penicillamine (D-PA). The effect of other coexisting analytes does not affect the selective sensing behavior of D-PA. The mechanism of binding between HNNPs and D-PA was discussed on the basis of electrostatic interaction and adsorption phenomenon. The results interpreted by using DLS-Zeta sizer, Fluorescence lifetime measurements, conductometric titration supports the electrostatic adsorption between HNNPs and D-PA. The method has extremely low limit of detection (LOD) value 0.021 ppm is of significant as compared to reported methods. The proposed fluorescence quenching method was effectively used for quantitative estimation of D-PA from pharmaceutical medicine.

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Graphical Abstract The fluorescence quenching based selective recognition of D-Penicillamine (D-PA) by using Schiff base centered fluorescent organic nanoparticles was developed and successfully applied to quantitative determination of D-PA from pharmaceutical samples viz. capsule and tablet.

     

A simple and efficient one-pot novel synthesis of pyrazolo[3,4-b][1,8]naphthyridine and pyrazolo[3,4-d]pyrimido[1,2-a]pyrimidine derivatives as anti-inflammatory agents

Research on Chemical Intermediates - An efficient one-pot synthesis of novel pyrazolo[3,4-b][1,8]naphthyridine and pyrazolo[3,4-d]pyrimido[1,2-a]pyrimidine derivatives has been investigated from...     

Brønsted acidic ionic liquids promoted cyclocondensation reaction: Synthesis of 1,8-dioxo-octahydroxanthene

A new functionalized basic ionic liquid, 4-amino-1-(2,3-dihydroxy propyl) pyridinium hydroxide [ADPPY] [OH], has been introduced as a catalyst for the synthesis of tetrahydrobenzo[b]pyrans under mild conditions. The desired products can be separated directly from the reaction mixture with high purity. Only 10 mol% catalyst was needed with a sequestration time of 10 min. In addition, the ionic liquid used can be regenerated and recycled several times without significant loss of activity.