Multifaceted strategy for the synthesis of diverse 2,2'-bithiophene derivatives.

New catalytically or high pressure activated reactions and routes, including coupling, double bond migration in allylic systems, and various types of cycloaddition and dihydroamination have been used for the synthesis of novel bithiophene derivatives. Thanks to the abovementioned reactions and routes combined with non-catalytic ones, new acetylene, butadiyne, isoxazole, 1,2,3-triazole, pyrrole, benzene, and fluoranthene derivatives with one, two or six bithiophenyl moieties have been obtained. Basic sources of crucial substrates which include bithiophene motif for catalytic reactions were 2,2'-bithiophene, gaseous acetylene and 1,3-butadiyne.

Dielectric relaxation in weakly ergodic dilute dipole systems.

We introduce a method for calculating dipole correlations in systems containing hopping processes exhibiting weak ergodicity breaking. Modeled after the original Kirkwood-Fröhlich theory, the new method provides a bridge extending Fröhlich's insights from the realm of rigid dipoles into weakly non-ergodic fluctuating virtual dipolar entities. Relevant for the investigation of any system containing transport processes, it provides a testable parameter derived primarily from the static dielectric parameters. Three examples of systems including porous silicon, porous glass, and ferroelectric crystals are brought to demonstrate the model's versatility, including direct confirmation of Fröhlich's original idea.

High-pressure experiments as a novel perspective to study the molecular dynamics of glass-forming materials confined at the nanoscale.

Herein, we report the pioneering high-pressure dielectric studies on the dynamics of a model van der Waals glass-forming liquid bisphenol-A diglycidyl ether (DGEBA) infiltrated into anodic aluminum oxide (AAO) templates of the mean pore sizes, d = 150 and d = 18 nm. It was found that although the shape of the structural relaxation process varies with the confinement, it remains constant under varying thermodynamic conditions for a given pore diameter. Consequently, the time-temperature-pressure (TTP) rule satisfied for the majority of bulk substances is also obeyed for the spatially restricted liquid. We have also shown for the first time that there is a decoupling between the core and interfacial mobility at elevated pressure. Moreover, it was noted that the structural dynamics of the former fraction of molecules becomes systematically shorter with respect to the bulk DGEBA during the compression. The enhanced structural dynamics of the core material, as well as the varying pressure coefficients of the glass transition temperature of the interfacial and core molecules, have been discussed in the context of a distinct evolution in their free volume/density packing with respect to the bulk DGEBA, and a change in the interfacial tension, which may lead to the enhanced wettability of the liquid adsorbed onto the pore walls under different thermodynamic conditions. The performed high-pressure measurements offer novel perspectives to explore the combination of two different effects, compression and confinement, which might be a breakthrough in the study of the glass transition phenomenon and the behavior of soft materials confined at the nanoscale.

Effect of Flexibility and Nanotriboelectrification on the Dynamic Reversibility of Water Intrusion into Nanopores: Pressure-Transmitting Fluid with Frequency-Dependent Dissipation Capability.

In this article, the effect of a porous material's flexibility on the dynamic reversibility of a nonwetting liquid intrusion was explored experimentally. For this purpose, high-pressure water intrusion together with high-pressure in situ small-angle neutron scattering were applied for superhydrophobic grafted silica and two metal-organic frameworks (MOFs) with different flexibility [ZIF-8 and Cu2(tebpz) (tebpz = 3,3',5,5'tetraethyl-4,4'-bipyrazolate)]. These results established the relation between the pressurization rate, water intrusion-extrusion hysteresis, and porous materials' flexibility. It was demonstrated that the dynamic hysteresis of water intrusion into superhydrophobic nanopores can be controlled by the flexibility of a porous material. This opens a new area of applications for flexible MOFs, namely, a smart pressure-transmitting fluid, capable of dissipating undesired vibrations depending on their frequency. Finally, nanotriboelectric experiments were conducted and the results showed that a porous material's topology is important for electricity generation while not affecting the dynamic hysteresis at any speed.

The liquid-glass and liquid-liquid transitions of TPP at elevated pressure.

We studied the polyamorphism of the liquid triphenyl phosphite by means of broadband dielectric spectroscopy at ambient and elevated (p=500 MPa) pressures. The effect of pressure on fragility, liquid-liquid phase transition, and its kinetics is discussed in relation to the two-order-parameter model proposed by Tanaka. The experimental evidence in support of this model is presented.

Mechanical, Thermal, and Electrical Energy Storage in a Single Working Body: Electrification and Thermal Effects upon Pressure-Induced Water Intrusion-Extrusion in Nanoporous Solids.

This paper presents the first experimental evidence of pronounced electrification effects upon reversible cycle of forced water intrusion-extrusion in nanoporous hydrophobic materials. Recorded generation of electricity combined with high-pressure calorimetric measurements improves the energy balance of {nanoporous solid + nonwetting liquid} systems by compensating mechanical and thermal energy hysteresis in the cycle. Revealed phenomena provide a novel way of "mechanical to electrical" and/or "thermal to electrical" energy transformation with unprecedented efficiency and additionally open a perspective to increase the efficiency of numerous energy applications based on such systems taking advantage of electricity generation during operational cycle.

Dynamics of α-tetralone at elevated pressure and in mixture with oligostyrene.

By using the dielectric relaxation method, we studied molecular dynamics of α-tetralone. Our purpose was to reveal the molecular origin of secondary processes observed for this very simple-structured molecule. To this end, we carried out dielectric measurements at both ambient and elevated pressure of neat α-tetralone and in mixture with oligostyrene. By means of both experimental observations and theoretical calculations, we proved that one of the secondary relaxations has the intramolecular origin, while the other is undoubtedly the intermolecular process called Johari-Goldstein relaxation characteristic of the glassy state.

Glass transition dynamics of room-temperature ionic liquid 1-methyl-3-trimethylsilylmethylimidazolium tetrafluoroborate.

The conductivity relaxation dynamics of the room-temperature ionic liquid 1-methyl-3-trimethylsilylmethylimidazolium tetrafluoroborate ([Si-MIm][BF(4)]) have been studied by broadband conductivity relaxation measurements at ambient pressure and elevated pressures up to 600 MPa. For the first time, several novel features of the dynamics have been found in a room-temperature ionic liquid. In the electric loss modulus M″(f) spectra, a resolved secondary ß-conductivity relaxation appears, and its relaxation time τ(ß) shifts on applying pressure in concert with the relaxation time τ(α) of the primary α-conductivity relaxation. The spectral dispersion of the α-conductivity relaxation, as well as the fractional exponent (1 - n) of the Kohlrausch-Williams-Watts function that fits the spectral dispersion, is invariant to various combinations of pressure and temperature that keep τ(α) constant. Moreover, τ(ß) is unchanged. Thus the three quantities, τ(α), τ(ß), and n, are coinvariant to changes in pressure and temperature. This strong connection to the α-conductivity relaxation shown by the ß-conductivity relaxation in [Si-MIm][BF(4)] indicates that it is the analogue of the Johari-Goldstein ß-relaxation in nonionically conducting glass-formers. The findings have fundamental implications on theoretical interpretation of the conductivity relaxation processes and glass transition in ionic liquids. It is also the first time such a secondary conductivity relaxation or the primitive conductivity relaxation of the coupling model has been fully resolved and identified in M″(f) in any ionically conducting material that we know of.

Note: New feedthrough insulation method for the dielectric spectroscopy under ultrahigh pressure conditions.

We present a new technique to prepare insulated channels for the high pressure cell used in broadband dielectric spectroscopy. The cell resists corrosion or other chemical reactions from the reactive sample liquids. The cell maintains electrical insulation between electrode contacts better than 100 GOmega as well as good mechanical properties in broad temperature range of -80 to +100 degrees C and under extremely high pressures up to 1.8 GPa.