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Gold nanoparticles (AuNPs) have been synthesized directly inside liposomes using honey as a reducing agent. The obtained aggregates, named Cassyopea® Gold due to the method used for their preparation, show remarkable properties as reactors and carriers of the investigated AuNPs. A mean size of about 150 nm and negative surface charge of -46 mV were measured for Cassyopea® Gold through dynamic light scattering and zeta potential measurements, respectively. The formation of the investigated gold nanoparticles into Cassyopea® liposomes was spectroscopically confirmed by the presence of their typical absorption band at 516 nm. The catalytic activity of the combined liposome–AuNP nanocomposites was tested via the thermal cis–trans isomerization of resonance-activated 4-methoxyazobenzene (MeO-AB). The kinetic rate constants (kobs) determined at 25 °C in the AuNP aqueous solution and in the Cassyopea® Gold samples were one thousand times higher than the values obtained when performing MeO-AB cis–trans conversion in the presence of pure Cassyopea®. The results reported herein are unprecedented and point to the high versatility of Cassyopea® as a reactor and carrier of metal nanoparticles in chemical, biological, and technological applications. [ABSTRACT FROM AUTHOR]

Solute-solvent interactions on the keto-enol tautomerism of 2-nitrocyclohexanone in several organic solvents and room-temperature ionic liquids (RTILs) are analyzed in terms of multiparameter equations. Permittivity and cohesive pressure values of the RTILs, unavailable by direct measurements are derived.

The equilibrium constants for ion pair formation of pyridines are analyzed by spectrophotometric titration with trifluoroacetic acid in different ionic liquids. The basicity order is the same in ionic liquids and in water, whereas pyridine basicity is less sensitive to the substituent effect in ionic liquids than in water.

The solvent effect on the rate of tautomerization of 2-nitrocyclohexanone in several organic solvents has depended on the permittivity of the solvent, but a different behavior is seen on some ionic liquids (ILs). The kinetic results are discussed in terms of the Bronsted equation, which have shown that on passing from molecular solvents to ILs the transition state structure of the enolization reaction has become markedly enolate-like.

The studies about the keto-enol tautomerism of 2-nitrocyclohexanne (2-NCH) which was carried out in aqueous solution under different experimental conditions is presented.

The inductively coupled plasma optical emission spectrometry (ICP‐OES) is a high resolution spectroscopic technique based on the emission intensity at specific wavelengths of a given element within the sample to obtain both qualitative and quantitative information about ions concentration in aqueous solution. The concentration of Ag+ in aqueous solution from negatively charged silver nanoparticles (AgNPs) has been determined by ion selective electrode (ISE) analysis at room temperature. The tested AgNPs solutions have been electrochemically prepared without using any coating agent. The obtained data have been compared to those obtained from the same samples by using ICP‐OES. The good correlation between the two techniques highlights that ISE could be successfully applied as valid alternative to ICP‐OES to determine the silver ion concentration in the investigated conditions. High level of reproducibility, accurate measurements and affordability represent the main advantages of the method described herein. [ABSTRACT FROM AUTHOR]

BMIM PF6 (1-butyl-3-methylimidazolium hexafluorophosphate) and BMIM Tf2N (1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) are two conventional room-temperature ionic liquids widely employed and investigated as reaction media. Despite the presence of the same imidazolium ring in their structure they are different in many chemical and physical properties due to the nature of the anions. The thermal cis-trans isomerization of an electronically activated azobenzene have been used as reaction model to compare the behavior of PF6- and Tf2N-. Rotation is the mechanism by which the investigated azobenzene is converted into the trans isomer spontaneously in the dark both in BMIM PF6 and in BMIM Tf2N. The kinetic rate constants of the process have been determined at different temperatures and the activation energies of the reaction have been calculated according to the Arrhenius and Eyring equations. The results presented herein highlight different solute-solvent interactions involving the PF6- and Tf2N- anions during the cis-trans isomerization. [ABSTRACT FROM AUTHOR]

Dispersions of single-walled carbon nanotubes (SWNTs) have been prepared by using the room-temperature ionic liquid [BMIM][BF4] (1-butyl-3-methylimidazolium tetrafluoroborate), the triblock copolymer Pluronic L121 [poly(ethylene oxide)5-poly(propylene oxide)68-poly(ethylene oxide)5] and the non-ionic surfactant Triton X-100 (TX100) in the pure state. The size of the SWNTs aggregates and the dispersion degree in the three viscous systems depend on the sonication time, as highlighted by UV/Vis/NIR spectroscopy and optical microscopy analysis. A nonlinear increase in conductivity can be observed as a function of the SWNTs loading, as suggested by electrochemical impedance spectroscopy. The generation of a three-dimensional network of SWNTs showing a viscoelastic gel-like behavior above a critical percolation concentration has been found at 25 °C in all the investigated systems by oscillatory rheology measurements. [ABSTRACT FROM AUTHOR]