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19 pages, 4221 KiB

Open AccessArticle

The Versatile Photo-Thermal Behaviour of a 2-Hydroxyazobenzene

by Pier Luigi Gentili, Antonio Capaccioni, Raimondo Germani and Simona Fantacci

Molecules 2023, 28(3), 1183; https://doi.org/10.3390/molecules28031183 - 25 Jan 2023

Viewed by 1361

Photochromic compounds are employed in implementing neuron surrogates. They will boost the development of neuromorphic engineering in wetware. In this work, the photochromic behaviours of (E)-3,4,6-trichloro-2-(p-diazenil)-phenol (t-DZH) and its conjugated phenoxide base (t-DZ) have been [...] Read more.

Photochromic compounds are employed in implementing neuron surrogates. They will boost the development of neuromorphic engineering in wetware. In this work, the photochromic behaviours of (E)-3,4,6-trichloro-2-(p-diazenil)-phenol (t-DZH) and its conjugated phenoxide base (t-DZ) have been investigated experimentally in three different media: (1) pure acetonitrile, (2) in water and acetonitrile mixed in a 1/1 volume ratio, and (3) in an aqueous micellar solution of 3-(N,N-Dimethylmyristylammonio)propanesulfonate (SB3-14). The analysis of the spectral and kinetic features of t-DZH and t-DZ has been supported by quantum-mechanical DFT calculations, the maximum entropy method, and the determination of their colourability (

C

). The versatility of t-DZH and t-DZ makes them promising molecular probes of micro-environments and potential ingredients of photochemical oscillators required for implementing pacemaker neurons capable of communicating through optical signals in wetware. Full article

(This article belongs to the Special Issue Cutting-Edge Physical Chemistry Research in Europe)

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16 pages, 2884 KiB

Open AccessArticle

Low Energy Electron Attachment by Some Chlorosilanes

by Bartosz Michalczuk, Wiesława Barszczewska, Waldemar Wysocki and Štefan Matejčík

Molecules 2021, 26(16), 4973; https://doi.org/10.3390/molecules26164973 - 17 Aug 2021

Viewed by 1656

Abstract

In this paper, the rate coefficients (k) and activation energies (E_a) for SiCl₄, SiHCl₃, and Si(CH₃)₂(CH₂Cl)Cl molecules in the gas phase were measured using the pulsed Townsend technique. [...] Read more.

In this paper, the rate coefficients (k) and activation energies (E_a) for SiCl₄, SiHCl₃, and Si(CH₃)₂(CH₂Cl)Cl molecules in the gas phase were measured using the pulsed Townsend technique. The experiment was performed in the temperature range of 298–378 K, and carbon dioxide was used as a buffer gas. The obtained k depended on temperature in accordance with the Arrhenius equation. From the fit to the experimental data points with function described by the Arrhenius equation, the activation energies (E_a) were determined. The obtained k values at 298 K are equal to (5.18 ± 0.22) × 10⁻¹⁰ cm³·s⁻¹, (3.98 ± 1.8) × 10⁻⁹ cm³·s⁻¹ and (8.46 ± 0.23) × 10⁻¹¹ cm³·s⁻¹ and E_a values were equal to 0.25 ± 0.01 eV, 0.20 ± 0.01 eV, and 0.27 ± 0.01 eV for SiHCl₃, SiCl₄, and Si(CH₃)₂(CH₂Cl)Cl, respectively. The linear relation between rate coefficients and activation energies for chlorosilanes was demonstrated. The DFT/B3LYP level coupled with the 6-31G(d) basis sets method was used for calculations of the geometry change associated with negative ion formation for simple chlorosilanes. The relationship between these changes and the polarizability of the attaching center (α_centre) was found. Additionally, the calculated adiabatic electron affinities (AEA) are related to the α_centre. Full article

(This article belongs to the Special Issue Cutting-Edge Physical Chemistry Research in Europe)

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18 pages, 5787 KiB

Open AccessArticle

Mechanisms of Tebuconazole Adsorption in Profiles of Mineral Soils

by Marcin Siek, Tadeusz Paszko, Maria Jerzykiewicz, Joanna Matysiak and Urszula Wojcieszek

Molecules 2021, 26(16), 4728; https://doi.org/10.3390/molecules26164728 - 04 Aug 2021

Cited by 2 | Viewed by 1643

Abstract

The study attempted to identify the soil components and the principal adsorption mechanisms that bind tebuconazole in mineral soils. The K_F values of the Freundlich isotherm determined in 18 soils from six soil profiles in batch experiments after 96 h of shaking [...] Read more.

The study attempted to identify the soil components and the principal adsorption mechanisms that bind tebuconazole in mineral soils. The K_F values of the Freundlich isotherm determined in 18 soils from six soil profiles in batch experiments after 96 h of shaking ranged from 1.11 to 16.85 μg¹^−1/n (mL)^1/n g⁻¹, and the exponent 1/n values from 0.74 to 1.04. The adsorption of tebuconazole was inversely correlated with the soil pH. Both neutral and protonated forms of this organic base were adsorbed mainly on the fraction of humins. The adsorption of the protonated form increased in the presence of hydrogen cations adsorbed in the soil sorption sites. Fourier transform infrared spectroscopy coupled with the molecular modeling studies and partial least squares regression analysis indicated that the tebuconazole molecule is bound in the organic matter through the formation of hydrogen bonds as well as hydrophobic and π–π interactions. Ion exchange was one of the adsorption mechanisms of the protonated form of this fungicide. The created mathematical model, assuming that both forms of tebuconazole are adsorbed on the organic matter and adsorption of the protonated form is affected by the potential acidity, described its adsorption in soils well. Full article

(This article belongs to the Special Issue Cutting-Edge Physical Chemistry Research in Europe)

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12 pages, 2994 KiB

Open AccessEditor’s ChoiceArticle

Operando Raman Shift Replaces Current in Electrochemical Analysis of Li-ion Batteries: A Comparative Study

by Mariusz Radtke and Christian Hess

Molecules 2021, 26(15), 4667; https://doi.org/10.3390/molecules26154667 - 01 Aug 2021

Cited by 3 | Viewed by 2942

Abstract

Li-rich and catalytically active

γ

-

L i_{x} V_{2} O_{5}

(x = 1.48) was investigated as a cathode for its heterogeneous charge transfer kinetics. Using a specially designed two-electrode system lithium half cell, Butler–Volmer analysis was performed, and Raman spectra [...] Read more.

Li-rich and catalytically active

γ

-

L i_{x} V_{2} O_{5}

(x = 1.48) was investigated as a cathode for its heterogeneous charge transfer kinetics. Using a specially designed two-electrode system lithium half cell, Butler–Volmer analysis was performed, and Raman spectra were acquired in 18 mV intervals. A direct correlation was observed between the Raman shift of the active modes

A_{g}

,

B_{g}

,

A_{u}

, and

B_{u}

, and the development of the Faraday current at the working electrode. The Raman intensity and the Raman shift were implemented to replace the current in a Tafel plot used for the analysis of Butler–Volmer kinetics. Striking similarities in the charge transfer proportionality constants

α

were found for current and Raman-based analysis. The potential of this new method of Raman-aided electrochemical detection at the diffraction limit is discussed. Full article

(This article belongs to the Special Issue Cutting-Edge Physical Chemistry Research in Europe)

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10 pages, 1070 KiB

Open AccessArticle

The Additive Influence of Propane-1,2-Diol on SDS Micellar Structure and Properties

by Martina Gudelj, Paola Šurina, Lucija Jurko, Ante Prkić and Perica Bošković

Molecules 2021, 26(12), 3773; https://doi.org/10.3390/molecules26123773 - 21 Jun 2021

Cited by 4 | Viewed by 2166

Abstract

Micellar systems are colloids with significant properties for pharmaceutical and food applications. They can be used to formulate thermodynamically stable mixtures to solubilize hydrophobic food-related substances. Furthermore, micellar formation is a complex process in which a variety of intermolecular interactions determine the course [...] Read more.

Micellar systems are colloids with significant properties for pharmaceutical and food applications. They can be used to formulate thermodynamically stable mixtures to solubilize hydrophobic food-related substances. Furthermore, micellar formation is a complex process in which a variety of intermolecular interactions determine the course of formation and most important are the hydrophobic and hydrophilic interactions between surfactant–solvent and solvent–solvent. Glycols are organic compounds that belong to the group of alcohols. Among them, propane-1,2-diol (PG) is a substance commonly used as a food additive or ingredient in many cosmetic and hygiene products. The nature of the additive influences the micellar structure and properties of sodium dodecyl sulfate (SDS). When increasing the mass fraction of propane-1,2-diol in binary mixtures, the c.m.c. values decrease because propane-1,2-diol is a polar solvent, which gives it the ability to form hydrogen bonds, decreasing the cohesivity of water and reducing the dielectric constant of the aqueous phase. The values of

Δ G_{m}^{0}

are negative in all mixed solvents according to the reduction in solvophobic interactions and increase in electrostatic interaction. With the rising concentration of cosolvent, the equilibrium between cosolvent in bulk solution and in the formed micelles is on the side of micelles, leading to the formation of micelles at a lower concentration with a small change in micellar size. According to the ¹H NMR, with the addition of propylene glycol, there is a slight shift of SDS peaks towards lower ppm regions in comparison to the D₂O peak. The shift is more evident with the increase in the amount of added propane-1,2-diol in comparison to the NMR spectra of pure SDS. Addition of propane-1,2-diol causes the upfield shift of the protons associated with hydrophilic groups, causing the shielding effect. This signifies that the alcohol is linked with the polar head groups of SDS due to its proximity to the SDS molecules. Full article

(This article belongs to the Special Issue Cutting-Edge Physical Chemistry Research in Europe)

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15 pages, 4049 KiB

Open AccessArticle

Lipid Nanoparticles Loaded with Iridoid Glycosides: Development and Optimization Using Experimental Factorial Design

by Marta Dąbrowska, Eliana B. Souto and Izabela Nowak

Molecules 2021, 26(11), 3161; https://doi.org/10.3390/molecules26113161 - 25 May 2021

Cited by 4 | Viewed by 1923

Abstract

Lipid nanoparticles based on multiple emulsion (W/O/W) systems are suitable for incorporating hydrophilic active substances, including iridoid glycosides. This study involved optimization of composition of lipid nanoparticles, incorporation of active compounds (aucubin and catalpol), evaluation of stability of the resulting nanocarriers, and characterization [...] Read more.

Lipid nanoparticles based on multiple emulsion (W/O/W) systems are suitable for incorporating hydrophilic active substances, including iridoid glycosides. This study involved optimization of composition of lipid nanoparticles, incorporation of active compounds (aucubin and catalpol), evaluation of stability of the resulting nanocarriers, and characterization of their lipid matrix. Based on 3² factorial design, an optimized dispersion of lipid nanoparticles (solid lipid:surfactant—4.5:1.0 wt.%) was developed, predisposed for the incorporation of iridoid glycosides by emulsification-sonication method. The encapsulation efficiency of the active substances was determined at nearly 90% (aucubin) and 77% (catalpol). Regarding the stability study, room temperature was found to be the most suitable for maintaining the expected physicochemical parameter values (particle size < 100 nm; polydispersity index < 0.3; zeta potential > |± 30 mV|). Characterization of the lipid matrix confirmed the nanometer size range of the resulting carriers (below 100 nm), as well as the presence of the lipid in the stable β’ form. Full article

(This article belongs to the Special Issue Cutting-Edge Physical Chemistry Research in Europe)

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13 pages, 1352 KiB

Open AccessArticle

X-ray and UV Radiation Damage of dsDNA/Protein Complexes

by Paweł Wityk, Dorota Kostrzewa-Nowak, Beata Krawczyk, Michał Michalik and Robert Nowak

Molecules 2021, 26(11), 3132; https://doi.org/10.3390/molecules26113132 - 24 May 2021

Cited by 3 | Viewed by 2355

Abstract

Radiation and photodynamic therapies are used for cancer treatment by targeting DNA. However, efficiency is limited due to physico-chemical processes and the insensitivity of native nucleobases to damage. Thus, incorporation of radio- and photosensitizers into these therapies should increase both efficacy and the [...] Read more.

Radiation and photodynamic therapies are used for cancer treatment by targeting DNA. However, efficiency is limited due to physico-chemical processes and the insensitivity of native nucleobases to damage. Thus, incorporation of radio- and photosensitizers into these therapies should increase both efficacy and the yield of DNA damage. To date, studies of sensitization processes have been performed on simple model systems, e.g., buffered solutions of dsDNA or sensitizers alone. To fully understand the sensitization processes and to be able to develop new efficient sensitizers in the future, well established model systems are necessary. In the cell environment, DNA tightly interacts with proteins and incorporating this interaction is necessary to fully understand the DNA sensitization process. In this work, we used dsDNA/protein complexes labeled with photo- and radiosensitizers and investigated degradation pathways using LC-MS and HPLC after X-ray or UV radiation. Full article

(This article belongs to the Special Issue Cutting-Edge Physical Chemistry Research in Europe)

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14 pages, 853 KiB

Open AccessArticle

Anion–Anion Interactions in Aerogen-Bonded Complexes. Influence of Solvent Environment

by Anna Grabarz, Mariusz Michalczyk, Wiktor Zierkiewicz and Steve Scheiner

Molecules 2021, 26(8), 2116; https://doi.org/10.3390/molecules26082116 - 07 Apr 2021

Cited by 13 | Viewed by 2173

Abstract

Ab initio calculations are applied to the question as to whether a AeX₅⁻ anion (Ae = Kr, Xe) can engage in a stable complex with another anion: F⁻, Cl⁻, or CN⁻. The latter approaches the [...] Read more.

Ab initio calculations are applied to the question as to whether a AeX₅⁻ anion (Ae = Kr, Xe) can engage in a stable complex with another anion: F⁻, Cl⁻, or CN⁻. The latter approaches the central Ae atom from above the molecular plane, along its C₅ axis. While the electrostatic repulsion between the two anions prevents their association in the gas phase, immersion of the system in a polar medium allows dimerization to proceed. The aerogen bond is a weak one, with binding energies less than 2 kcal/mol, even in highly polar aqueous solvent. The complexes are metastable in the less polar solvents THF and DMF, with dissociation opposed by a small energy barrier. Full article

(This article belongs to the Special Issue Cutting-Edge Physical Chemistry Research in Europe)

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11 pages, 1722 KiB

Open AccessArticle

Highly Porous Carbons Synthesized from Tannic Acid via a Combined Mechanochemical Salt-Templating and Mild Activation Strategy

by Sylwia Głowniak, Barbara Szczęśniak, Jerzy Choma and Mietek Jaroniec

Molecules 2021, 26(7), 1826; https://doi.org/10.3390/molecules26071826 - 24 Mar 2021

Cited by 13 | Viewed by 2865

Abstract

Highly porous activated carbons were synthesized via the mechanochemical salt-templating method using both sustainable precursors and sustainable chemical activators. Tannic acid is a polyphenolic compound derived from biomass, which, together with urea, can serve as a low-cost, environmentally friendly precursor for the preparation [...] Read more.

Highly porous activated carbons were synthesized via the mechanochemical salt-templating method using both sustainable precursors and sustainable chemical activators. Tannic acid is a polyphenolic compound derived from biomass, which, together with urea, can serve as a low-cost, environmentally friendly precursor for the preparation of efficient N-doped carbons. The use of various organic and inorganic salts as activating agents afforded carbons with diverse structural and physicochemical characteristics, e.g., their specific surface areas ranged from 1190 m²·g⁻¹ to 3060 m²·g⁻¹. Coupling the salt-templating method and chemical activation with potassium oxalate appeared to be an efficient strategy for the synthesis of a highly porous carbon with a specific surface area of 3060 m²·g⁻¹, a large total pore volume of 3.07 cm³·g⁻¹ and high H₂ and CO₂ adsorption capacities of 13.2 mmol·g⁻¹ at −196 °C and 4.7 mmol·g⁻¹ at 0 °C, respectively. The most microporous carbon from the series exhibited a CO₂ uptake capacity as high as 6.4 mmol·g⁻¹ at 1 bar and 0 °C. Moreover, these samples showed exceptionally high thermal stability. Such activated carbons obtained from readily available sustainable precursors and activators are attractive for several applications in adsorption and catalysis. Full article

(This article belongs to the Special Issue Cutting-Edge Physical Chemistry Research in Europe)

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31 pages, 884 KiB

Open AccessPerspective

A Role for Bottom-Up Synthetic Cells in the Internet of Bio-Nano Things?

by Pasquale Stano, Pier Luigi Gentili, Luisa Damiano and Maurizio Magarini

Molecules 2023, 28(14), 5564; https://doi.org/10.3390/molecules28145564 - 21 Jul 2023

Cited by 4 | Viewed by 2203

Abstract

The potential role of bottom-up Synthetic Cells (SCs) in the Internet of Bio-Nano Things (IoBNT) is discussed. In particular, this perspective paper focuses on the growing interest in networks of biological and/or artificial objects at the micro- and nanoscale (cells and subcellular parts, [...] Read more.

The potential role of bottom-up Synthetic Cells (SCs) in the Internet of Bio-Nano Things (IoBNT) is discussed. In particular, this perspective paper focuses on the growing interest in networks of biological and/or artificial objects at the micro- and nanoscale (cells and subcellular parts, microelectrodes, microvessels, etc.), whereby communication takes place in an unconventional manner, i.e., via chemical signaling. The resulting “molecular communication” (MC) scenario paves the way to the development of innovative technologies that have the potential to impact biotechnology, nanomedicine, and related fields. The scenario that relies on the interconnection of natural and artificial entities is briefly introduced, highlighting how Synthetic Biology (SB) plays a central role. SB allows the construction of various types of SCs that can be designed, tailored, and programmed according to specific predefined requirements. In particular, “bottom-up” SCs are briefly described by commenting on the principles of their design and fabrication and their features (in particular, the capacity to exchange chemicals with other SCs or with natural biological cells). Although bottom-up SCs still have low complexity and thus basic functionalities, here, we introduce their potential role in the IoBNT. This perspective paper aims to stimulate interest in and discussion on the presented topics. The article also includes commentaries on MC, semantic information, minimal cognition, wetware neuromorphic engineering, and chemical social robotics, with the specific potential they can bring to the IoBNT. Full article

(This article belongs to the Special Issue Cutting-Edge Physical Chemistry Research in Europe)

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