Band 235, Heft 9

Protic ionic liquids (PILs) being intrinsic proton conducting ionic species are considered as potential green electrolytes for study of electrocatalytic reactions and for fabrication of IL-based fuel cells (FCs) and batteries. We have prepared a sulfate anion based protic ionic liquid (PIL), triethylammonium sulfate (TEAS) through a reaction involving transfer of proton from H 2 SO 4 to triethylamine (TEA). 1 H NMR and FT-IR spectroscopic techniques were employed for confirmation of the synthesis of TEAS and water content of the PIL was quantified using coulometric Karl–Fischer (KF) titration. 1 H NMR and FT-IR analysis confirm the synthesis of the PILs and KF-titration analysis shows that TEAS contains 1.43 w/w % water. Electrical conductivity of TEAS was determined at different temperatures showing that the PIL has excellent ionic conductivity that enhances with rise in temperature of the medium. The temperature dependence of the conductivity of the PIL follows the Arrhenius equation as the log σ versus 1/ T plot is linear. The electrochemical windows (EWs) of the electrolyte were found using cyclic voltammetry at Pt and Au working electrodes and found to decrease with increase in temperature of the medium. The data revealed that the surfaces of the electrodes are covered with oxide layers due to oxidation of trace water (1.43 w/w %) present in the PIL. The oxide layers growth increase and their onset potential moves to less positive values as the temperature of the PILs is increased. The data was compared with the literature and would be helpful in understanding of the surface electrochemistry in this neoteric medium for being used as potential electrolyte in industry for various electrochemical applications.

In this study, an extremely effective electromembrane extraction (EME) method was developed for the selective extraction of Cu(II) followed by Red-Green-Blue (RGB) detection. The effective parameters optimized for the extraction efficiency of EME include applied voltage, extraction time, supported liquid membrane (SLM) composition, pH of acceptor/donor phases, and stirring rate. Under optimized conditions, Cu(II) was extracted from a 3 mL aqueous donor phase to 8 µL of 100 mM HCl acceptor solution through 1-octanol SLM using an applied voltage of 50 V for 15 min. The proposed method provides a working range of 0.1–0.75 µg·mL −1 with 0.03 µg·mL −1 limit for detection. Finally, the developed technique was applied to different environmental water samples for monitoring environmental pollution. Obtained relative recoveries were within the range of 93–106%. The relative standard deviation (RSD) and enhancement factor (EF) were found to be ≤4.8% and 100 respectively. We hope that this method can be introduced for quantitative determination of Cu(II) as a fast, simple, portable, inexpensive, effective, and precise procedure.

The analysis of the NLO properties of 4-methoxy-1-naphthol (4M1N) reveals that this molecule has the value of polarizability tensor, α, more than 340% greater than that obtained, at the same level of theory, for urea molecule. This improvement grows to 500% when the second-order hyperpolarizability is considered. Calculations performed within LR-PCM-B3LYP/6-311+G(3 d ,2 p ) model proved that embedding of 4M1N in the polymer matrix significantly improved these results suggesting applications of 4M1N as the cheap and effective NLO material. The molecule was also studied, both theoretically and experimentally, to determine its full vibrational characterisation and structural description. Calculations were performed with HF, MP2, SVWN and B3LYP methods, in two, varying in size, basis sets, to find optimized structures, conformational isomers and UV–VIS, IR and Raman spectra. The accordance of simulated oscillation and absorption spectra with experimental ones is very good; IR values are slightly red-shifted. NBO charge distribution analysis was made to generate frontier orbitals and find most reactive parts of the molecule.

Flavonoids amongst the class of secondary metabolites possess numerous health benefits, are known for its use in pharmaceutical industry. Quercetin, a flavonoid has more prominent medical advantages however its utilization is constrained because of various instability and insolubility issues and therefore, taken into consideration for studying its physico-chemical properties. In view of that, the thermodynamic and thermoacoustic properties of quercetin were examined in presence of cationic surfactant cetyltrimethylammonium bromide (CTAB) at different hydroethanolic concentrations and temperatures. The conductivity studies were used to calculate change in enthalpy (∆ H o m ), change in entropy (∆ S o m ) and change in Gibbs free Energy (∆ G o m ) of micellization. The interactions between quercetin and CTAB were found to be endothermic, entropically controlled and spontaneous. Further, ultrasonic sound velocity and density studies were carried out and utilized for the calculation of thermoacoustic parameters i.e. apparent molar volume and apparent molar compressibility. Thermoacoustic properties revealed that at higher surfactant concentration, hydrophobic interactions are dominant. The results suggested that the flavonoid-surfactant interactions in hydroethanolic solutions is more favourable as compared with aqueous solution. Overall, the data is favourable for the framework to be used for detailing advancement, drug development, drug industry, pharmaceutical industry, medical administration and formulation development studies.

This paper focusses on the synthesis of cobalt vanadate (CoVO 4 ) nanoparticles (NPs) by precipitation method. This was further augmented by assistance from microwave. Nanotechnology has been a wonderful tool with the promising application in different fields of life. The CoVO 4 NPs synthesized by microwave assisted precipitation method was characterized by advanced techniques such as X-ray powder diffraction (XRD), Energy dispersive X-ray analysis (EDX), Scanning electron microscopy (SEM), Ultraviolet visible spectroscopy (UV–vis) techniques. Rhodamine B (RhB) dye was used to evaluate the photo catalytic activity (PCA) of NPs by degradation of dye. The conditions were optimized for maximum degradation of dye. The NPs were in the nano flowers form and the size was ≤100 nm. The results regarding degradation of RhB was through PCA were promising; 83% dye was degraded at pH 10, reaction time 160 min and catalyst dose 1 g. It may conclude that the synthesized NPs could further be employed for possible treatment of industrial effluents particularly textile industry.

The designing of a dye sensitised solar cell (DSSC) is one of the frontiers in harvesting solar energy as it provides an alternative to economic photovoltaic devices with increased efficiency. In this manuscript, we report a new methodology using experimental and theoretical data for the evaluation of the photosensitiser activity of organic dyes using theoretical simulations and experimental cell efficiency data. As a representative example, we designed a series of 54 novel pyrazole derivatives which are subjected to TD-DFT simulations (CAM-B3LYP/6-311G++ (2d, p)) and photovoltaic modelling. Data from computational simulations, as well as known experimental cells, are used for the calculation of photovoltaic efficiency. We selected pyrazole derivatives because of its proven use in DSSC as an effective dopant in a blended polymer electrolyte in nanocrystalline DSSC. Fine-tuning with the effect of substitution and with the π spacers at the ortho, meta and para positions for −OCH 3 , −OH, −CHO, −NO 2 respectively were done. Enhanced efficiency of 7.439% was observed as compared to the standard cell of efficiency of 5.530%. An increase in efficiency was not observed with the effect of π spacers. The newly designed dyes demonstrate desirable energetic and spectroscopic parameter that can lead to efficient metal-free organic dye sensitiser for DSSC’s. The main advantage of this strategy is the incorporation of both simulated and experimental data. It will reduce the possible errors from the simulations and also, helps in performing time-consuming experimental studies.