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A new approach for the development of nano-sized spectroscopic-based early-warning sensors using molecular electrostatic potentials (MEP) and molecular vibronics (MV) was presented. The use of MEPs allow us to sense and detect specific molecules in elaborated arrays of logical gates which provide the signature of the trapped species and a decision signal of the results of the sensing operation. Molecular vibronics is used to activate/deactivate, control and program the detection process as well as to transmit the information to and from nano-micro interfaces that allow the interaction with microelectronic systems. In order to develop this scenario, it is needed to explain the exact reasons, from an atomistic point of view rather than using phenomenological models the effects of molecules on nanoclusters. We present here a study of silicon-phenyl complexes.

Intermolecular interaction energies for molecular dimers of benzene, indene, naphthalene, phenanthrene, cholesterol and glycyrrhetinic acid have been calculated according to the CVFF empirical force field of the DISCOVER program. The parallel orientations (side by-side) turned out to be the energetically most favourable ones, in agreement with the parametrization of Gay–Berne potentials. The energies of the T-shape and in-plane (end-to-end) orientations of the entirely asymmetric molecules cholesterol and glycyrrhetinic acid depend strongly on the actual atomic positions. This shows the extent to which the shape and charges of molecules determine all possible orientations and interaction energies in molecular ensembles.

We calculate here the Raman frequencies of some lattice modes as a function of pressure at constant temperatures for the solid and liquid phases of benzene. The observed data for the molar volume from literature is used to calculate the Raman frequencies through the mode Grüneisen parameter in benzene.

Our calculated frequencies are in good agreement with the observed data when the mode Grüneisen parameter is taken as a constant at one particular pressure in solid benzene.

It is shown here that the Raman frequencies can be calculated from the volume data, as demonstrated for benzene here.

Tungsten carbide nanoparticles were synthesized successfully by DC arc discharge plasma process with 23 A discharge current at atmospheric pressure, in which tungsten positive electrode reacted with carbon black produced from the benzene cracking. The XRD results indicate that the samples consist of carbon black, WC and W₂ C. The TEM micrographs show that the tungsten carbide particles range from 3 to 7 nm in size, and are composed of WC and W₂C.

This paper presents the results of a study of the dielectric constant of solutions of a polar liquid in a nonpolar solvent: chlorobenzene–benzene, chlorobenzene–hexane. The measurements were carried out at a wavelength $\lambda =12.80$cm in the temperature range from $-80^{\circ }$C to $20^{\circ }$C. The studies were carried out using the dielectric spectroscopy method. This method allows a more detailed study of the dielectric properties of the objects of study due to the large equilibrium (“static”) dielectric constant of the object. The temperature dependence of the dielectric relaxation time of molecules in the liquid and solid states of the studied solutions is determined. It has been established that with increasing concentration (0.300, 0.562, 0.794, 1.000 for a chlorobenzene–hexane solution and 0.179, 0.368, 0.567, 0.778, 1.000 for a chlorobenzene–benzene solution) of the halogen substituent, the relaxation time increases. The measurement results of dielectric constant ${\epsilon }^{\prime }$ and absorption coefficient ${\epsilon }^{\prime \prime }$ obtained for concentrated solutions chlorobenzene–benzene, chlorobenzene–n–hexane at wavelengths $\lambda =12$, 80 and $\lambda =3,26$cm at temperature $20^{\circ }$C are given in the paper. The static dielectric constant is obtained at a frequency of 1MHz. The obtained experimental values ${\epsilon }^{\prime }$, ${\epsilon }^{\prime \prime }$ and ${\epsilon }_0$ of investigated systems in (${\epsilon }^{\prime }$, ${\epsilon }^{\prime \prime }$) plane locate on the semi-circle the center of which is on ${\epsilon }^{\prime }$ axis. In this case, the high-frequency limit value of $\epsilon \infty$ dielectric coefficient exceeds the corresponding n₂ refraction index square. The macroscopic and molecular relaxation times are calculated on the base of experimental data. The thermodynamic quantities characterizing the process of dielectric relaxation are calculated for solutions of chlorobenzene–benzene, chlorobenzene–hexane. It has been determined that the height of the potential barrier separating the two equilibrium positions of a polar molecule is greatest in the state of a pure polar liquid and decreases with dilution in a nonpolar solvent.

The co-adsorption of carbon monoxide and benzene on Co(0001) has been studied using density functional calculations. We used the ordered surface unit cell. A comparison of the co-adsorption with CO and benzene two-dimensional networks is also given. The electronic structure reveals that the CO orbitals interact with benzene and Co layer. Regarding the bonding, the Co–Co overlap population decrease 18% after benzene adsorption and increase a little after CO adsorption with a net 14.6% decrease in the co-adsorption system. The CO–benzene interaction is shown by the changes in the C–O (CO) and C–H (benzene) bonds.

The adsorption of small organic molecules on silicon surfaces has been long a subject of investigations, as it provides the fundamental basis of silicon-based technologies in many fields. Several approaches were used, both theoretical and experimental, on many types of adsorbate-substrate systems aiming at determining preferential sites and geometries of adsorption, stable configurations, transition barriers, adsorption mechanisms, electronic structures among others. The research efforts, though, did not always bring to conclusive arguments and on some systems investigations are still going on following the evolution of the experimental techniques and computational methods. In this review, two case studies are reported: benzene and methanol on Si(100)2$\times$1, i.e. examples of a molecular and a dissociative adsorption. The adsorption of benzene on Si(100)2$\times$1 is still an open case, as it may adsorb in di-$\sigma$ or tetra-$\sigma$ bonded configurations, but contrasting evidences have been reported so far, on which of the two is the most stable one and the debate is still open. The adsorption of methanol is less controversial and it is widely accepted it is dissociative with breakage of the O–H at low coverages. But also in this case, investigations are going on to elucidate the adsorption mechanism.

Density functional theory method was applied to investigate adsorption of thiophene, benzene, and hexane in Na-, Ag-, and Cu-exchanged mordenite (MOR). A cluster model containing 16 tetrahedral atoms was constructed as structure model of MOR. The charge-balancing metallic ions (Na⁺, Ag⁺, and Cu⁺) were introduced to produce the Lewis acid site (LAS). The acidic strength was estimated by calculating adsorption energy of NH₃ in the model. The equilibrium configurations, Mulliken charge populations, and adsorption energies of thiophene, benzene, and hexane in models were calculated and analyzed. For the adsorbates investigated, interaction strengths followed the decreasing order of Cu–MOR > Ag–MOR > Na–MOR that agreed well with their Lewis acidic strengths. The interaction strengths followed the order of thiophene ≈ benzene > hexane in Na–MOR, and thiophene > benzene > hexane in Cu–MOR and Ag–MOR. Moreover, the interaction mechanisms of thiophene and benzene in Cu–MOR and Ag–MOR were investigated by the natural bond orbital (NBO) analysis. Furthermore, similar calculations were carried out for the adsorption of thiophene, benzene, and hexane in the naked Na⁺, Cu⁺, and Ag⁺ for comparison.

Transformation of methane, the most abundant and the least reactive compound of natural gas to valuable products is one of the most difficult chemical problems of great practical importance. In Nature, methane monooxygenase enzymes transform methane to methanol in water under physiological conditions. However, chemical analogs for such a transformation are unknown. Here, we show the mild and efficient aqueous oxidation of methane by hydrogen peroxide, an ecologically and biologically relevant oxidant catalyzed by supported μ-nitrido diiron phthalocyanine dimer, (FePc^tBu₄)₂N. This bio-inspired complex containing a stable Fe–N–Fe motif catalyzes the oxidation of methane to methanol which is further transformed to formaldehyde and formic acid as is demonstrated using ¹³CH₄ and ¹⁸O labelling. (FePc^tBu₄)₂N-H₂O₂ system shows a high activity in the oxidation of benzene to phenol which occurs via formation of benzene oxide and exhibits NIH shift typically accociated with biological oxidation. Mechanistic features of oxidation of methane and benzene as well as detected intermediate hydroperoxo- and high valent oxo diiron complexes support an O-atom transfer reaction mechanism relevant to bio-oxidation.

Some people think that carbon and sustainable development are not compatible. This textbook shows that carbon dioxide (CO₂) from the air and bio-carbon from biomass are our best allies in the energy transition, towards greater sustainability. We pose the problem of the decarbonation (or decarbonization) of our economy by looking at ways to reduce our dependence on fossil carbon (coal, petroleum, natural gas, bitumen, carbonaceous shales, lignite, peat). The urgent goal is to curb the exponential increase in the concentration of carbon dioxide in the atmosphere and hydrosphere (Figures 1.1 and 1.2) that is directly related to our consumption of fossil carbon for our energy and materials The goal of the Paris agreement (United Nations COP 21, Dec. 12, 2015) of limiting the temperature increase to 1.5 degrees (compared to the pre-industrial era, before 1800) is becoming increasingly unattainable (Intergovermental Panel on Climate Change (IPCC), report of Aug. 6, 2021). On Aug. 9, 2021 Boris Johnson, prime minister of the United Kingdom, declared that coal needs to be consigned to history to limit global warming. CO₂ has an important social cost…

There are mines of elemental carbon such as graphite. It is the most stable form of elemental carbon at 25°C, under 1 atm (Section 3.7). A second form of pure or nearly pure elemental carbon is represented by diamonds (Section 3.12). Other forms of elemental carbon are produced by combustion or heat treatment of wood (Section 3.6), bio-polymers such as paper, cotton (cellulose), or synthetic polymers such as viscose (Section 11.10.1) and polyacrylonitrile (Section 8.2.7). Nanoparticles such as graphene (Section 3.7), fullerenes (Section 3.8), nanotubes (Section 3.9), and quantum dots of carbon (Section 3.10) are available that find biomedical applications and are used in the manufacture of nanometric objects useful for electronics, optoelectronics, photophysics, energy and the environment protection. Nanoparticles must be handled with care as they can be toxic…

Today, fossil carbon provides us with fuels (energy), polymers (packaging, insulating and building materials, household utensils, glues, coatings, textiles, 3D-printing inks, furnitures, vehicle parts, toys, electronic and medical devices, etc.) and biologically active substances (drugs (Chapter 9), flavorings, fragrances, food additives, plant protection products, etc.). In this chapter we discover the modern materials of our civilization which are very often polymers derived from oil. They are referred to as “plastics” (annual world production: 380 × 10⁶ tons). Their production consumes 8% of the crude oil extracted (ca. 5 billion tons per year). An increasing part of the plastics originates from renewable resources (less than 10% today, see Section 11.10, bio-sourced plastics). Plastics make life easy for us, but at the underestimated cost of damage to our environment (Figure 8.1) and our health. They contaminate the hydrosphere and the agricultural soil. The atmosphere is also contaminated by microplastics…

A new approach for the development of nano-sized spectroscopic-based early-warning sensors using molecular electrostatic potentials (MEP) and molecular vibronics (MV) was presented. The use of MEPs allow us to sense and detect specific molecules in elaborated arrays of logical gates which provide the signature of the trapped species and a decision signal of the results of the sensing operation. Molecular vibronics is used to activate/deactivate, control and program the detection process as well as to transmit the information to and from nano-micro interfaces that allow the interaction with microelectronic systems. In order to develop this scenario, it is needed to explain the exact reasons, from an atomistic point of view rather than using phenomenological models the effects of molecules on nanoclusters. We present here a study of silicon-phenyl complexes.