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Symmetry
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Chemistry: Symmetry/Asymmetry—Feature Papers and Reviews
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Chemistry: Symmetry/Asymmetry—Feature Papers and Reviews

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

Deadline for manuscript submissions: 31 July 2025 | Viewed by 10036

Special Issue Editor

Prof. Dr. György Keglevich

E-Mail Website
Guest Editor
Department of Organic Chemistry and Technology, Budapest University of Technology and Economics, H-1521 Budapest, Hungary
Interests: organophosphorus chemistry; green chemistry; microwave chemistry; catalysts; ionic liquids
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Symmetry and asymmetry are fascinating topics in chemistry. "Chemistry: Symmetry/Asymmetry. Feature Papers and Reviews" is a Special Issue that covers a wide range of topics related to symmetry or asymmetry in chemistry. Papers submitted to Symmetry may include all types of symmetry-related problems in chemistry. All organic chemists, theoretical chemists, and crystal chemists are invited to submit papers focusing on, but not limited to, the following emerging research topics in related areas:

  • Chirality;
  • Enantiomers;
  • Diastereomers;
  • Molecular symmetry;
  • Plane of symmetry;
  • Asymmetric carbon;
  • Optically active compounds;
  • Stereocenter;
  • Homochirality;
  • Symmetry elements;
  • Mirror plane;
  • Molecular chirality;
  • Asymmetric synthesis;
  • Optical resolution;
  • X-ray crystallography;
  • X-ray structures;
  • Crystal structures;
  • Homochirality in chemistry and biochemistry;
  • Symmetry and spectroscopy;
  • Symmetry and isomerism;
  • Homochirality in the origin of life;
  • Chirogenesis;
  • Stereoselective synthesis;
  • Chiral ligands.

Prof. Dr. György Keglevich
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

  • chirality
  • enantiomers
  • diastereomers
  • molecular symmetry
  • plane of symmetry
  • asymmetric carbon
  • optically active compounds
  • stereocenter
  • homochirality
  • symmetry elements
  • mirror plane
  • molecular chirality
  • asymmetric synthesis
  • optical resolution
  • X-ray crystallography
  • X-ray structures
  • crystal structures
  • homochirality in chemistry and biochemistry
  • symmetry and spectroscopy

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Published Papers (9 papers)

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Research

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24 pages, 17380 KiB  
Article
Solvatochromic Analysis of Triton X-100 in Binary Mixtures
by Ecaterina Ambrosi, Alexandru Zara, Dana Ortansa Dorohoi and Dan-Gheorghe Dimitriu
Symmetry 2025, 17(2), 199; https://doi.org/10.3390/sym17020199 - 27 Jan 2025
Viewed by 280
Abstract
Binary solvent mixtures of the non-ionic surfactant Triton X-100 with water, methanol, ethanol, and 1-propanol, respectively, were investigated by solvatochromic studies. The absorption spectral bands of methyl red dye, used as a solvatochromic probe, were recorded in ternary solutions prepared with different mole [...] Read more.
Binary solvent mixtures of the non-ionic surfactant Triton X-100 with water, methanol, ethanol, and 1-propanol, respectively, were investigated by solvatochromic studies. The absorption spectral bands of methyl red dye, used as a solvatochromic probe, were recorded in ternary solutions prepared with different mole ratios between Triton X-100 and water/alcohols. The Kamlet–Abboud–Taft model was applied to estimate the contribution of each type of intermolecular interaction to the total shift of the electronic absorption band of the solute. The composition of the solute molecule’s first solvation shell was comparatively estimated by using three models: the statistical cell model of ternary solutions, the Suppan model, and the Bosch–Rosés model. The statistical cell model allows the estimation of the difference between the interaction energies in the solute–solvent pairs of molecules. The Bosch–Rosés model provided important information on the 1:1 complex formed between Triton X-100 and water/alcohol molecules, as well as on the symmetry/asymmetry related to the binary mixtures in the cybotactic region of the solute’s molecule. Full article
(This article belongs to the Special Issue Chemistry: Symmetry/Asymmetry—Feature Papers and Reviews)
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15 pages, 2686 KiB  
Article
Quantum-Chemical Investigations on the Structure and Stability of Mixed Trimers Containing HC3N in Combination with H2C2 and/or HCN Analyzed by QTAIM, NBO and SAPT Methods
by Andrea Pietropolli Charmet, Paolo Stoppa, Alessandra De Lorenzi and Patrizia Canton
Symmetry 2025, 17(1), 140; https://doi.org/10.3390/sym17010140 - 18 Jan 2025
Viewed by 455
Abstract
The present work deals with the computational study of HC3N··HCN··H2C2-, (HC3N)2··H2C2-, and HC3N··(H2C2 [...] Read more.
The present work deals with the computational study of HC3N··HCN··H2C2-, (HC3N)2··H2C2-, and HC3N··(H2C2)2-mixed trimers. The different equilibrium structures of the different low-lying minima on the corresponding potential energy surface (PES) were accurately determined, and the relative stabilities were computed by extrapolation procedures to the complete basis set limit. For each mixed trimer, the non-covalent interactions ruling the structure of the most stable isomer were analyzed using the QTAIM (Quantum Theory of Atoms in Molecules) approach. Additional insights into these interactions were provided by the Natural Bond Orbital (NBO) and Symmetry-Adapted Perturbation Theory (SAPT) methods. These results can be used to assist further theoretical investigations and experimental studies on the formation of larger molecules potentially relevant in astrochemistry. Full article
(This article belongs to the Special Issue Chemistry: Symmetry/Asymmetry—Feature Papers and Reviews)
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13 pages, 1499 KiB  
Article
Fungal Biocatalysis in Stereoselective Oxidation of 2-Phenylethanol
by Agnieszka Raczyńska, Beata Szmigiel-Merena, Małgorzata Brzezińska-Rodak, Magdalena Klimek-Ochab and Ewa Żymańczyk-Duda
Symmetry 2025, 17(1), 17; https://doi.org/10.3390/sym17010017 - 26 Dec 2024
Viewed by 311
Abstract
Three fungal strains were employed for the stereoselective oxidation of the cheap and commercially available substrate 2-phenylethanol, which resulted in chiral building blocks being received. The whole-cell biocatalysts were as follows: Beauveria bassiana DSM 1344, Beauveria brongniartii DSM 6651, and Rhizopus arrhizus DSM [...] Read more.
Three fungal strains were employed for the stereoselective oxidation of the cheap and commercially available substrate 2-phenylethanol, which resulted in chiral building blocks being received. The whole-cell biocatalysts were as follows: Beauveria bassiana DSM 1344, Beauveria brongniartii DSM 6651, and Rhizopus arrhizus DSM 1185. The main product of Beauveria bassiana bioconversion was 1-phenylethane-1,2-diol, obtained, depending on the form of the biocatalyst, as an R-enantiomer (e.g., 99.9%) with fresh biomass application or as a racemic mixture in cases of immobilization in agar-agar. The best and most innovative results for the synthesis of the R-enantiomer of diol were received under precisely defined conditions as a result of a scaling study conducted on an automatic batch reactor. This is a pioneering result, since, in previous studies, fresh mycelium of Aspergillus niger resulted in this product being received as the (S) enantiomer. Also, the use of Rhizopus arrhizus DSM 1185 (immobilized in polyurethane foams) presented important results, as the bioconversion of phenyl ethanol led, indeed, to the racemic mixture of 1-phenylethane-1,2-diol but was accompanied by a noticeable tyrosol synthesis, which had not been reported previously. Full article
(This article belongs to the Special Issue Chemistry: Symmetry/Asymmetry—Feature Papers and Reviews)
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12 pages, 1583 KiB  
Article
Complete Epoxy Phosphonate Conversion to Dimethyl (1E)-3-Hydroxyprop-1-Enylphosphonate with Photobiocatalysts’ Assistance
by Sunday Ocholi Samson, Monika Serafin-Lewańczuk, Małgorzata Brzezińska-Rodak, Magdalena Klimek-Ochab and Ewa Żymańczyk-Duda
Symmetry 2024, 16(12), 1676; https://doi.org/10.3390/sym16121676 - 18 Dec 2024
Viewed by 538
Abstract
Phosphonates derivatives are compounds of interests and are applied as drugs of, e.g., antibacterial antiviral activities, connected with their inhibitory activity towards different enzymes, which is related to the configuration of particular compound isomers. The biological synthesis of such molecules is the method [...] Read more.
Phosphonates derivatives are compounds of interests and are applied as drugs of, e.g., antibacterial antiviral activities, connected with their inhibitory activity towards different enzymes, which is related to the configuration of particular compound isomers. The biological synthesis of such molecules is the method of choice and can be carried out using enzymes or whole cells from organisms. Photobiocatalysts employed in the bioconversion of epoxymethyl dimethyl phosphonate are able to convert this substrate into a pure geometric isomer of the unsaturated product, dimethyl (1E)-3-hydroxyprop-1-enylphosphonate, which is a rare and expensive compound of high added value. Six different strains were screened towards dimethyl epoxy phosphonate and in the case of Synechococcus bigranulatus, over 99% conversion was achieved. The product structure was confirmed with Mass Spectroscopy (MS); 1H, 13C, 31P, and 2D Nuclear Magnetic Resonance (NMR); and Infrared Spectroscopy (IR). Full article
(This article belongs to the Special Issue Chemistry: Symmetry/Asymmetry—Feature Papers and Reviews)
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36 pages, 13944 KiB  
Article
Enumeration of n-Dimensional Hypercubes, Icosahedra, Rubik’s Cube Dice, Colorings, Chirality, and Encryptions Based on Their Symmetries
by Krishnan Balasubramanian
Symmetry 2024, 16(8), 1020; https://doi.org/10.3390/sym16081020 - 9 Aug 2024
Viewed by 1779
Abstract
The whimsical Las Vegas/Monte Carlo cubic dice are generalized to construct the combinatorial problem of enumerating all n-dimensional hypercube dice and dice of other shapes that exhibit cubic, icosahedral, and higher symmetries. By utilizing powerful generating function techniques for various irreducible representations, we [...] Read more.
The whimsical Las Vegas/Monte Carlo cubic dice are generalized to construct the combinatorial problem of enumerating all n-dimensional hypercube dice and dice of other shapes that exhibit cubic, icosahedral, and higher symmetries. By utilizing powerful generating function techniques for various irreducible representations, we derive the combinatorial enumerations of all possible dice in n-dimensional space with hyperoctahedral symmetries. Likewise, a number of shapes that exhibit icosahedral symmetries such as a truncated dodecahedron and a truncated icosahedron are considered for the combinatorial problem of dice enumerations with the corresponding shapes. We consider several dice with cubic symmetries such as the truncated octahedron, dodecahedron, and Rubik’s cube shapes. It is shown that all enumerated dice are chiral, and we provide the counts of chiral pairs of dice in the n-dimensional space. During the combinatorial enumeration, it was discovered that two different shapes of dice exist with the same chiral pair count culminating to the novel concept of isochiral polyhedra. The combinatorial problem of dice enumeration is generalized to multi-coloring partitions. Applications to chirality in n-dimension, molecular clusters, zeolites, mesoporous materials, cryptography, and biology are also pointed out. Applications to the nonlinear n-dimensional hypercube and other dicey encryptions are exemplified with romantic, clandestine messages: “I love U” and “V Elope at 2”. Full article
(This article belongs to the Special Issue Chemistry: Symmetry/Asymmetry—Feature Papers and Reviews)
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27 pages, 9799 KiB  
Article
On the Solvatochromism of Fluorescein Sodium
by Corina Cheptea, Alexandru Zara, Ecaterina Ambrosi, Ana Cezarina Morosanu, Maria Diaconu, Mihaela Miron, Dana Ortansa Dorohoi and Dan Gheorghe Dimitriu
Symmetry 2024, 16(6), 673; https://doi.org/10.3390/sym16060673 - 30 May 2024
Cited by 1 | Viewed by 1449
Abstract
Fluorescein sodium is a very important compound for a wide spectrum of applications, from which medical applications prevail. Despite this, there are very few studies in the literature related to the structure and fundamental properties of fluorescein sodium and its solutions, with most [...] Read more.
Fluorescein sodium is a very important compound for a wide spectrum of applications, from which medical applications prevail. Despite this, there are very few studies in the literature related to the structure and fundamental properties of fluorescein sodium and its solutions, with most of the studies dealing with fluorescein. The purpose of the present article is to determine some parameters of the fluorescein sodium molecule approaching the quantum-mechanical modeling and experimental solvatochromism in both binary and ternary solutions. For data analysis, several theoretical models were applied. The results highlight the intermolecular interactions involved in the spectral shift of the electronic absorption band of fluorescein sodium when dissolved in different solvents or binary solvents and allowed the estimation of the difference between the interaction energy in molecular pairs of the type of fluorescein sodium − solvent 1 and fluorescein sodium − solvent 2. By applying a variational method, the dipole moment in the first excited state of the fluorescein sodium molecule and the angle between the dipole moments in the ground and excited states, respectively, were estimated. These results are useful for a better understanding of the behavior of fluorescein sodium when dissolved in different solvents or combinations of solvents, to develop new practical applications. Full article
(This article belongs to the Special Issue Chemistry: Symmetry/Asymmetry—Feature Papers and Reviews)
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Review

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63 pages, 14545 KiB  
Review
Sum-Frequency Generation Spectroscopy at Aqueous Electrochemical Interfaces
by Ba Lich Pham, Alireza Ranjbari, Abderrahmane Tadjeddine, Laetitia Dalstein and Christophe Humbert
Symmetry 2024, 16(12), 1699; https://doi.org/10.3390/sym16121699 - 21 Dec 2024
Viewed by 834
Abstract
The electrochemical interface (EI) is the determining factor in the yield and mechanism of sustainable energy storage and conversion systems due to its intrinsic functionality as a dynamic junction with the symmetry breaking of the molecular arrangement for complex reaction fields of mass [...] Read more.
The electrochemical interface (EI) is the determining factor in the yield and mechanism of sustainable energy storage and conversion systems due to its intrinsic functionality as a dynamic junction with the symmetry breaking of the molecular arrangement for complex reaction fields of mass transport and heterogeneous electron transfer. At the EI, the externally applied potential stimulus drives the formation of the electrical double layer (EDL) and governs the adsorption of interfacial adsorbate species in aqueous electrolyte solutions. Water and its aqueous electrolyte systems are integral and quintessential elements in the technological innovation of various fields such as environmental sciences, electrocatalysis, photocatalysis, and biochemistry. Although deciphering the structure and orientation of water molecules at the electrode–electrolyte interface in a quantitative analysis is of utmost importance, assessing chemical phenomena at the buried EI was rather challenging due to the intricacy of selecting interface-specific methodologies. Based on the non-centrosymmetry of the interfaces’ electronic properties, sum-frequency generation (SFG) spectroscopy has been manifested to be specifically well suited for probing the EI with detailed and comprehensive characteristics of adsorbates’ chemical structures and electrochemical events. In this review, we holistically engage in a methodical and scrupulous assessment of the fundamental EDL models and navigate towards the connection of the renowned Stark effect and potential dependence of SFG spectra at heterogeneous electrode–electrolyte interfaces. We dissect the development, advantages, and available geometrical configurations of in situ SFG spectroscopy in harnessing the EI. A broad spectrum of applications in unraveling the water orientations and rationalizing the convoluted mechanism of fuel-generated electrocatalytic reactions with particular encumbrances and potential resolutions is underscored by leveraging SFG spectroscopy. Full article
(This article belongs to the Special Issue Chemistry: Symmetry/Asymmetry—Feature Papers and Reviews)
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27 pages, 1672 KiB  
Review
Analyzing the Chiral Purity of Pharmaceuticals: The Application of Cyclodextrin-Based Chiral Selectors in Capillary Electrophoresis
by Gabriel Hancu, Adriana Modroiu, Denisa Gabriela Stroia and Alexandra Uilăcan
Symmetry 2024, 16(10), 1354; https://doi.org/10.3390/sym16101354 - 12 Oct 2024
Viewed by 1676
Abstract
The current review provides a focused analysis of the application of capillary electrophoresis (CE) techniques to determine the chiral purity of pharmaceuticals, with a specific emphasis on cyclodextrin- (CD) based chiral selectors (CSs), highlighting advancements, methodologies, and trends in this area as reported [...] Read more.
The current review provides a focused analysis of the application of capillary electrophoresis (CE) techniques to determine the chiral purity of pharmaceuticals, with a specific emphasis on cyclodextrin- (CD) based chiral selectors (CSs), highlighting advancements, methodologies, and trends in this area as reported in studies published from 2010 to 2024. The review emphasizes CE’s evolution as a critical tool in this field, discussing its advantages, such as high efficiency, flexibility, relatively low costs, and minimal environmental impact, which make it well-suited for modern pharmaceutical applications. Additionally, it underscores the importance of CE in meeting stringent regulatory requirements for chiral drug substances. A significant shift in method optimization has occurred in the last ten years, shifting from the traditional One-Factor-at-a-Time (OFAT) strategy to the Design-of-Experiments (DoE) approach; this shift has enabled more systematic and robust method development. Furthermore, a common trend in recent years is the application of Quality-by-Design (QbD) principles in method development and optimization, ensuring higher reliability and efficiency. Additionally, there is an increasing focus on developing CE methods capable of detecting both achiral and chiral impurities simultaneously, which enhances the comprehensiveness of the analysis. This review seeks to guide future research and development in optimizing CE methodologies for pharmaceutical applications. Full article
(This article belongs to the Special Issue Chemistry: Symmetry/Asymmetry—Feature Papers and Reviews)
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30 pages, 15361 KiB  
Review
Medicinally Significant Enantiopure Compounds from Garcinia Acid Isolated from Garcinia gummi-gutta
by Simimole Haleema, Chithra Gopinath, Zabeera Kallingathodi, Grace Thomas and Prasad L. Polavarapu
Symmetry 2024, 16(10), 1331; https://doi.org/10.3390/sym16101331 - 9 Oct 2024
Viewed by 1408
Abstract
Garcinia gummi-gutta, commonly known as Garcinia cambogia (syn.), is a popular traditional herbal medicine known for its role in treating obesity, and has been incorporated into several nutraceuticals globally for this purpose. The fruit rind is also used as a food preservative [...] Read more.
Garcinia gummi-gutta, commonly known as Garcinia cambogia (syn.), is a popular traditional herbal medicine known for its role in treating obesity, and has been incorporated into several nutraceuticals globally for this purpose. The fruit rind is also used as a food preservative and a condiment because of its high content of hydroxycitric acid, which imparts a sharp, sour flavour. This review highlights the major bioactive compounds present in the tree Garcinia gummi-gutta, with particular emphasis on (2S, 3S)-tetrahydro-3-hydroxy-5-oxo-2,3-furan dicarboxylic acid, commonly referred to as garcinia acid. This acid can be isolated in large amounts through a simple procedure. Additionally, it explores the synthetic transformations of garcinia acid into biologically potent and functionally useful enantiopure compounds, a relatively under-documented area in the literature. This acid, with its six-carbon skeleton, a γ-butyrolactone moiety, and two chiral centres bearing chemically amenable functional groups, offers a versatile framework as a chiron for the construction of diverse molecules of both natural and synthetic origin. The synthesis of chiral 3-substituted and 3,4-disubstituted pyrrolidine-2,5-diones, analogues of the Quararibea metabolite—a chiral enolic-γ-lactone; the concave bislactone skeletons of fungal metabolites (+)-avenaciolide and (−)-canadensolide; the structural skeletons of the furo[2,3-b]furanol part of the anti-HIV drug Darunavir; (−)-tetrahydropyrrolo[2,1-a]isoquinolinones, an analogue of (−)-crispine A; (−)-hexahydroindolizino[8,7-b]indolones, an analogue of the naturally occurring (−)-harmicine; and furo[2,3-b]pyrroles are presented here. Full article
(This article belongs to the Special Issue Chemistry: Symmetry/Asymmetry—Feature Papers and Reviews)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Title: Lie Unitary approach for variational chemical dynamics in quantum computing
Authors: Jorge A. Morales
Affiliation: Texas Tech University, Dept. of Chemistry and Biochemistry 039

Title: Sum-frequency generation spectroscopy at the aqueous electrochemical interface
Authors: Ba Lich Pham; Alireza Ranjbari; Laetitia Dalstein; Christophe Humbert
Affiliation: Univ Paris-Sud, Université Paris-Saclay, Laboratoire de Chimie Physique, CNRS, Batiment 201 P2, 91405 Orsay, France

Title: Synthesis, X-ray diffraction and computational drug-likeness evaluation of new pyrrolo[1,2-a][1,10]phenanthrolines bearing a 9-cyano group
Authors: Mihaela Cristea; Amalia Stefaniu; Marcel Mirel Popa; Sergiu Shova; Constantin Drăghici; Mihai Răducă; Doriana Banu; Florea Dumitrascu
Affiliation: National Institute for R&D in Microtechnology, IMT Bucharest
Abstract: New 9-cyano-pyrrolo[1,2-a][1,10]phenanthrolines 5a–c, obtained by 1,3-dipolar cycloaddition reaction between the corresponding N-ylides of 1,10-phenanthrolinium bromides 2a–c generated in-situ and acrylonitrile as a dipolarophile, were investigated by single-crystal X-ray diffraction and computational studies to assess their druglikeness and evaluate their structure activity properties. The non-covalent interactions present within the supramolecular landscape of the new 9-cyano-pyrrolo[1,2-a][1,10]phenanthrolines were correlated with the SAR investigations with the aim to estimate the propensity for bioactivity of these compounds.

Title: ELECTROCHEMISTRY AND DFT CALCULATION ON TETRAHYDROACRIDINES
Authors: Eleonora-Mihaela Ungureanu
Affiliation: Faculty of Chemical Engineering and Biotechnologies, University “Politehnica” of Bucharest, Gheorghe Polizu 1–7, Romania 

Title: Asymmetric catalysis with a Type-B energetic feature?
Authors: James W. Lee
Affiliation: Old Dominion University Department of Chemistry and Biochemistry
Abstract: Currently, there is substantial scientific evidence for the existence of Type-B energetic processes on Earth, such as the naturally occurring transmembrane-electrostatically localized protons thermotrophic properties in life, which follows the first law of thermodynamics (conservation of mass and energy) but does not have to be constrained by the second law because its special asymmetric structure and/or function. In this article, we will review and discuss the possibility of a Type-B energetic feature in asymmetrically catalyzed biochemical and/or chemical processes that produce stereoisomers in L (S) and/or D (R) configurations. The biological amino acid synthesis pathways may represent naturally occurring asymmetrically catalyzed processes that produce amino acids solely in the L (S) configuration, which has a slightly lower entropy than that of the 50% L (S) and 50% D (R). Therefore, an asymmetrically catalyzed process that results in a product distribution substantially deviated from the typical 50% L (S) and 50% D (R) may have a Type-B energetic feature, although its overall energetics still appears as a Type-A energetic process with a substantial negative change of its Gibbs free energy.

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