Gorka Pera

Thermophysical study of 1-butyl-2-methylpyridinium tetrafluoroborate ionic liquid.

A thermophysical study of 1-butyl-2-methylpyridinium tetrafluoroborate in a wide range of temperatures has been performed. Thus, density, speed of sound, refractive index, kinematic viscosity, surface tension, and thermal properties have been measured, whereas coefficients of thermal expansion, molar refractions, dynamic viscosities, and entropies and enthalpies of surface formation per unit surface area at the studied temperatures have been calculated. Experimental results have been compared with those obtained for 1-butyl-3-methylpyridinium tetrafluoroborate and 1-butyl-4-methylpyridinium tetrafluoroborate to analyze the effect of the positional isomeric cationic structure on properties. A systematic characterization leads to understand the behavior of such compounds, being a fundamental step to develop their potential as new solvents.

Towards the Fabrication of the Top-Contact Electrode in Molecular Junctions by Photoreduction of a Metal Precursor

Langmuir films of 4-{[4-({4-[(trimethylsilyl)ethynyl]phenyl}ethynyl)phenyl]ethynyl} benzenaminium chloride ([1 H]Cl) undergo anion metathesis when assembled on an aqueous auric acid (HAuCl4 ) subphase. Subsequent transfer to solid supports gives well-formed Langmuir-Blodgett (LB) monolayers of [1 H]AuCl4 in which the trimethylsilyl group serves as the surface contacting group. Photoreduction of the aurate on these monolayers leads to the formation of metallic gold nanoislands, which were distributed over the surface of the film. Electrical properties of these nascent devices were determined by recording current-voltage (I-V) curves with conductive atomic force microscopy (c-AFM) using the PeakForce tunneling AFM (PF-TUNA) mode. This gives consistent sigmoidal I-V curves that are indicative of well-behaved junctions free of metallic filaments and short circuits. The photoreduction of a metal precursor incorporated onto monomolecular films is therefore proposed as an effective method for the fabrication of molecular junctions.

Refractive indices and molar refractions of binary mixtures formed by some cyclic ethers and isomeric chlorobutanes

Refractive indices of binary mixtures formed by a cyclic ether (tetrahydrofuran or tetrahydropyran) and each of the isomeric chlorobutanes (1-chlorobutane, 2-chlorobutane, 1-chloro-2-methylpropane and 2-chloro-2-methylpropane) have been measured at two temperatures, 298.15 K and 313.15 K. From experimental data, refractive index deviations and molar refractions have been calculated. Furthermore, several common mixing rules have been used to predict refractive indices of the mixtures from their experimental densities reported previously.