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Symmetry
Special Issues
From Nanoclusters to Nanoparticles: Symmetry, Theory, Experiments, and Applications
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From Nanoclusters to Nanoparticles: Symmetry, Theory, Experiments, and Applications

A special issue of Symmetry (ISSN 2073-8994). This special issue belongs to the section "Chemistry: Symmetry/Asymmetry".

Deadline for manuscript submissions: 31 May 2024 | Viewed by 2263

Special Issue Editor

Dr. Federico Palazzetti

E-Mail Website
Guest Editor
Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
Interests: physical chemistry; theoretical chemistry; molecular dynamics; molecular beams
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Nanoscience and nanotechnology have great potential to benefit society through the development of highly innovative materials in a wide variety of fields. Nanoclusters are aggregates formed by a small number of atoms and molecules, ranging from a few units up to a few hundred, and whose size does not exceed 2-3 nm. They can be bound by weak forces, such as van der Waals forces, or by very strong interactions, such as covalent bonds. Nanoparticles are clusters whose dimensions range from 2-3 nm up to 100 nm; they can be classified into different classes based on their properties, shapes, or sizes. Nanoclusters and nanoparticles have different physical and chemical properties from those of their larger material counterparts and are closely related to the number of components. For this reason, they are widely employed in the development of materials used in catalysis, medical applications, energy production and storage, and environmental protection.

It is my great pleasure to announce this Special Issue of Symmetry entitled “From Nanoclusters to Nanoparticles: Symmetry, Theory, Experiments, and Applications”. It is addressed to all scientists involved in the development of theories and experiments, especially those related to the study of the properties of symmetry, and applications of nanoclusters and nanoparticles.

Dr. Federico Palazzetti
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Symmetry is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • reaction dynamics
  • reaction mechanisms
  • symmetry properties of clusters
  • photochemistry
  • photodissociation dynamics
  • phase transitions
  • trajectory simulations
  • metal clusters
  • molecular clusters
  • ionic clusters

Published Papers (3 papers)

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Research

12 pages, 2291 KiB  
Article
Accelerated Stability Testing in Food Supplements Underestimates Shelf Life Prediction of Resveratrol with Super-Arrhenius Behavior
by Andrea Biagini, Nicola Refrigeri, Concetta Caglioti, Paola Sabbatini, Silvia Ticconi, Giada Ceccarelli, Rossana Giulietta Iannitti, Federico Palazzetti and Bernard Fioretti
Symmetry 2024, 16(4), 493; https://doi.org/10.3390/sym16040493 - 18 Apr 2024
Viewed by 363
Abstract
Thermo-oxidative stability testing plays a critical role in accurately predicting shelf life. These tests are performed in real time and under stress conditions, where degradation processes are accelerated by increasing storage conditions. In this study, high-performance liquid chromatography (HPLC) analyses were performed to [...] Read more.
Thermo-oxidative stability testing plays a critical role in accurately predicting shelf life. These tests are performed in real time and under stress conditions, where degradation processes are accelerated by increasing storage conditions. In this study, high-performance liquid chromatography (HPLC) analyses were performed to evaluate the degradation of resveratrol in nutraceutical tablets as a function of time under different storage conditions in terms of temperature and relative humidity (RH), namely 25 °C/60% RH, 30 °C/65% RH, and 40 °C/75% RH. The latter is an accelerated test and is used to estimate shelf life for long-term storage. Resveratrol is present in both pure form and as a solid dispersion on magnesium dihydroxide microparticles (Resv@MDH). Degradation kinetic constants were determined at 25 °C, 30 °C, and 40 °C, and the Arrhenius behavior of the kinetic constants as a function of temperature was verified. The main results of this work are as follows: (i) the stability of resveratrol in nutraceutical tablets is affected by temperature; (ii) the dependence of the kinetic constants on temperature does not follow the Arrhenius equation, determining an overestimation of the degradation rate at 25 °C; in this regard a modified version of the Arrhenius equation that takes into account the deviation from linearity has been used to estimate the dependence of the kinetic constant on the temperature. These results suggest that accelerated testing does not provide a general model for predicting the shelf life of foods and dietary supplements. The reason may be due to possible matrix effects that result in different degradation mechanisms depending on the temperature. In this regard, symmetry relationships in the kinetics of chemical reactions resulting from microscopic reversibility and their relationship to the deviation from the Arrhenius equation are discussed. However, further research is needed to characterize the degradation mechanisms at different temperatures. The results of these studies would allow accurate prediction of food degradation to improve food safety and risk management and reduce food waste. In addition, knowledge of stability processes is necessary to ensure the maintenance of physiological processes by dietary supplements. Full article
(This article belongs to the Special Issue From Nanoclusters to Nanoparticles: Symmetry, Theory, Experiments, and Applications)
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14 pages, 5347 KiB  
Article
Structure and Thermodynamics of Li+Arn Clusters beyond the Second Solvation Shell
by Jorge M. C. Marques and Frederico V. Prudente
Symmetry 2024, 16(2), 229; https://doi.org/10.3390/sym16020229 - 14 Feb 2024
Viewed by 593
Abstract
Small Li+Arn clusters are employed in this work as model systems to study microsolvation. Although first and second solvation shells are expected to be the most relevant ones for this type of atomic solvents, it is also interesting to explore [...] Read more.
Small Li+Arn clusters are employed in this work as model systems to study microsolvation. Although first and second solvation shells are expected to be the most relevant ones for this type of atomic solvents, it is also interesting to explore larger clusters in order to identify the influence of external atoms on structural and thermodynamic properties. In this work, we perform a global geometry optimization for Li+Arn clusters (with n = 41–100) and parallel tempering Monte Carlo (PTMC) simulations for some selected sizes. The results show that global minimum structures of large clusters always have 6 argon atoms in the first solvation shell while maintaining the number of 14 or 16 argon atoms in the second one. By contrast, third and fourth solvation shells vary significantly the number of argon atoms with the cluster size, and other shells can hardly be assigned due to the reduced influence of Li+ on the external argon atoms for large clusters. In turn, PTMC calculations show that the melting of the most external solvation shells of large microsolvation clusters occurs at T∼50K, which is independent of cluster size. Structural transitions can be observed between quasi-degenerated structures at low temperatures. Moreover, the present results highlight the fluxional character of the external solvation shells of these large Li+Arn clusters, which may be seen as typical “snowball” structures. Full article
(This article belongs to the Special Issue From Nanoclusters to Nanoparticles: Symmetry, Theory, Experiments, and Applications)
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13 pages, 2726 KiB  
Article
Revisiting the Absolute Configuration of Peyssonnoside A Using Vibrational Circular Dichroism Spectroscopy
by Andrew R. Puente, Bhuwan Khatri Chhetri, Julia Kubanek and Prasad L. Polavarapu
Symmetry 2024, 16(2), 133; https://doi.org/10.3390/sym16020133 - 23 Jan 2024
Viewed by 976
Abstract
Peyssonnoside A is an unusual natural product consisting of a diterpene unit and a sulfonated monosaccharide. The experimental and theoretical comparison of Optical Rotatory Dispersion (ORD) and quantitative Nuclear Magnetic Resonance (NMR) data provided strong evidence for the stereochemistry of the diterpene unit. [...] Read more.
Peyssonnoside A is an unusual natural product consisting of a diterpene unit and a sulfonated monosaccharide. The experimental and theoretical comparison of Optical Rotatory Dispersion (ORD) and quantitative Nuclear Magnetic Resonance (NMR) data provided strong evidence for the stereochemistry of the diterpene unit. However, predicted Vibrational Circular Dichroism (VCD) spectra of Peyssonnoside A at the B3LYP/6-311++G(2d,2p) level showed poor correlation to the corresponding experimental spectra, preventing independent absolute configuration (AC) determination from VCD analysis. New calculations using the B3PW91 functional and the 6-311G(3df,2pd) basis set suggest that we can now independently and confidently assign the AC of Peyssonnoside A through VCD analyses. The use of f-polarization functions is responsible for the current successful assignment, compared to previously failed VCD analysis. This study highlights two important points: (a) the importance of using multiple levels of theories for satisfactorily reproducing the experimental spectra and (b) for quantitative comparisons using similarity indices, it is important to consider not only the VCD spectra but also the corresponding absorption spectra. Full article
(This article belongs to the Special Issue From Nanoclusters to Nanoparticles: Symmetry, Theory, Experiments, and Applications)
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