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Novel Chirogenic Systems and Sensing Materials for Stereoselective Sensors Development
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Novel Chirogenic Systems and Sensing Materials for Stereoselective Sensors Development

A topical collection in Chemosensors (ISSN 2227-9040). This collection belongs to the section "Materials for Chemical Sensing".

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Editors

Prof. Dr. Victor Borovkov

E-Mail Website
Collection Editor
Department of Chemistry and Biotechnology, Tallinn University of Technology, Academia tee 15, 12616 Tallinn, Estonia
Interests: sensors; induced chirality; chirality transfer; supramolecular chirality; chiral chromophores; circular dichroism; chiral materials and surfaces
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Riina Aav

E-Mail Website
Collection Editor
Department of Chemistry and Biotechnology, School of Science, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
Interests: chiral compounds; synthesis of macrocycles; host-guest chemistry; chirality induction; cucurbiturils
Prof. Dr. Roberto Paolesse

E-Mail Website
Collection Editor
Dept. of Chemical Science and Technologies, University of Rome Tor Vergata, via della Ricerca Scientifica 1, 00133 Rome, Italy
Interests: chemical sensors; porphyrins; corroles; sensor arrays; supramolecular chemistry; nanostructured materials; thin films
Special Issues, Collections and Topics in MDPI journals
Dr. Manuela Stefanelli

E-Mail Website
Collection Editor
Department of Chemical Science and Technology (STC), University of Rome “Tor Vergata”, 00133 Rome, Italy
Interests: porphyrinoid synthesis; chiral porphyrin aggregates; chiral materials; stereoselective sensors
Dr. Donato Monti

E-Mail Website
Collection Editor
Department of Chemistry, Università La Sapienza, Piazzale Aldo Moro 5, 00185 Roma, Italy
Interests: supramolecular chirality; chiral assemblies; porphyrins; self-aggregation; chiral recognition

Topical Collection Information

Dear Colleagues,

Chirality (from the Greek word “kheir", meaning “hand”) is a fundamental concept that has been recognised in chemistry since the second half of nineteenth century. In fact, hard as they try, nobody could ever overestimate its importance, that extends from the synthesis of organic and inorganic compounds, pharmaceutical and biologically active molecules, theoretical studies and technological application, to understanding the basic principles and origin of the emergence of Life on our planet.

A chiral species is a single molecule or molecular assembly that cannot be superimposed with its mirror image. Chiral molecules are consequently present as two stereoisomers, called enantiomers, and, importantly, they are the main building blocks of living organism. On a daily basis, chiral molecules are conventionally used and produced by pharmaceutical, food, agrochemical, perfume, and cosmetics industries. As a result, chiral waste becomes an extremely important issue at present. Chiral compounds can be ecologically hazardous, due to their high biological activity, creating a global pollution problem. It is of note, that enantiomers have a different impact on living organisms making it extremely important to differentiate these stereoisomers, which is extremely a difficult and challenging task and usually requires highly specific and costly instruments. Yet, the stereoisomerism of contaminants is presently not considered in detail. For example, ~25% of all pesticides produced are chiral compounds and in many cases they are used as racemic mixtures, while about 70–80% of medical drugs are enantiopure molecules. In this context, the development of portable chemical sensors devices which are reliable, sensitive and rapid, capable of fast, simple and real-time in situ and on site analysis for sensing and discrimination of chiral molecules presents an attractive breakthrough target compared to existing standard instrumental methods.

Therefore, the aim of this Topical Collection is to highlight and overview all aspects of chiral pollution on environment and corresponding detection by using modern analytical approaches.

This issue will also include the design and fabrication of organic/inorganic as well as hybrid sensitive materials. Different aspects will be covered ranging, for example, from the synthesis of the proper building blocks and their characterization to their eventual deposition in solid-state.

All types of papers, including comprehensive reviews on general environmental issues, full experimental or theoretical papers, comments, and others are welcome for consideration.

Prof. Dr. Victor Borovkov
Prof. Dr. Riina Aav
Prof. Dr. Roberto Paolesse
Dr. Manuela Stefanelli
Dr. Donato Monti
Collection Editors

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 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

  • chiral pollutants
  • environment
  • chirality
  • stereoisomerism
  • enantiomers
  • chirality sensors
  • self-assembly
  • supramolecular systems

Published Papers (11 papers)

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2023

Jump to: 2022, 2021

22 pages, 9468 KiB  
Review
Research Progress on Chiral Supramolecular Sensors for Enantiomer Detection
by Xiao-Fan Wu, Qing-Mei Ge, Nan Jiang, Wen-Feng Zhao, Mao Liu, Hang Cong and Jiang-Lin Zhao
Chemosensors 2023, 11(5), 269; https://doi.org/10.3390/chemosensors11050269 - 01 May 2023
Cited by 1 | Viewed by 1741
Abstract
Chiral substances occur naturally in abiotic and living systems. The recognition and detection of chiral substances in the natural environment or their analysis and detection in biological systems are crucial. Chiral recognition is a research hotspot in clinical medicine, pharmacology, biochemistry, and other [...] Read more.
Chiral substances occur naturally in abiotic and living systems. The recognition and detection of chiral substances in the natural environment or their analysis and detection in biological systems are crucial. Chiral recognition is a research hotspot in clinical medicine, pharmacology, biochemistry, and other fields. Indeed, many researchers have developed various sensors with different functionalized materials for detecting and analyzing enantiomers. Supramolecular systems have important applications in the development of molecular recognition technologies, and the development of supramolecular chemistry is closely related to research on molecular devices. Therefore, this review summarizes the principle of chiral supramolecular sensors for the detection of enantiomers from the perspective of various sensor types, including optical, electrochemical, electrochemical luminescence, photoelectric, and supramolecular chemical sensors. This review also summarizes the relevant reports on chiral supramolecular sensors in the last five years. Finally, we highlight the prospects of supramolecular chiral sensors in future research. Full article
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11 pages, 1905 KiB  
Article
Bipolar Electrochemical Analysis of Chirality in Complex Media through Miniaturized Stereoselective Light-Emitting Systems
by Silvia Cauteruccio, Valentina Pelliccioli, Sara Grecchi, Roberto Cirilli, Emanuela Licandro and Serena Arnaboldi
Chemosensors 2023, 11(2), 131; https://doi.org/10.3390/chemosensors11020131 - 13 Feb 2023
Cited by 4 | Viewed by 1579
Abstract
Environmentally relevant contaminants endowed with chirality may include pharmaceutical compounds, flame retardants, perfluoroalkyl chemicals, pesticides, and polychlorinated biphenyls. Despite having similar physicochemical properties, enantiomers may differ in their biochemical interactions with enzymes, receptors, and other chiral molecules leading to different biological responses. In [...] Read more.
Environmentally relevant contaminants endowed with chirality may include pharmaceutical compounds, flame retardants, perfluoroalkyl chemicals, pesticides, and polychlorinated biphenyls. Despite having similar physicochemical properties, enantiomers may differ in their biochemical interactions with enzymes, receptors, and other chiral molecules leading to different biological responses. In this work, we have designed a wireless miniaturized stereoselective light-emitting system able to qualitatively detect a chiral contaminant (3,4-dihydroxyphenylalanine, DOPA) dissolved in reduced volumes (in the microliters range), through bipolar electrochemistry. The diastereomeric environment was created by mixing the enantiomers of an inherently chiral inductor endowed with helical shape (7,8-dipropyltetrathia[7]helicene) and the chiral probe (DOPA) in micro-solutions of a commercial ionic liquid. The synergy between the inductor, the applied electric field, and the chiral pollutant was transduced by the light emission produced from a miniaturized light-emitting diode (LED) exploited in such an approach as a bipolar electrode. Full article
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2022

Jump to: 2023, 2021

11 pages, 1731 KiB  
Article
Proline Enantiomers Discrimination by (L)-Prolinated Porphyrin Derivative Langmuir–Schaefer Films: Proof of Concept for Chiral Sensing Applications
by Gabriele Giancane, Rosanna Pagano, Mario Luigi Naitana, Gabriele Magna, Manuela Stefanelli, Donato Monti, Roberto Paolesse, Simona Bettini and Ludovico Valli
Chemosensors 2022, 10(8), 331; https://doi.org/10.3390/chemosensors10080331 - 13 Aug 2022
Cited by 1 | Viewed by 1533
Abstract
A porphyrin derivative functionalized with the L-enantiomer of proline amino acid was characterized at the air–pure water interface of the Langmuir trough. The porphyrin derivative was dissolved in dichloromethane solution, spread at the air–subphase interface and investigated by acquiring the surface pressure vs. [...] Read more.
A porphyrin derivative functionalized with the L-enantiomer of proline amino acid was characterized at the air–pure water interface of the Langmuir trough. The porphyrin derivative was dissolved in dichloromethane solution, spread at the air–subphase interface and investigated by acquiring the surface pressure vs. area per molecule Langmuir curves. It is worth observing that the behavior of the molecules of the porphyrin derivative floating film was substantially influenced by the presence of L-proline amino acid dissolved in the subphase (10−5 M); on the contrary, the physical chemical features of the floating molecules were only slightly influenced by the D-proline dissolved in the subphase. Such an interesting chirality-driven selection was preserved when the floating film was transferred onto solid supports by means of the Langmuir–Schaefer method, but it did not emerge when a spin-coating technique was used for the layering of the tetrapyrrolic derivatives. The obtained results represent proof of concept for the realization of active molecular layers for chiral discrimination: porphyrin derivatives, due to their intriguing spectroscopic and supramolecular properties, can be functionalized with the chiral molecule that should be detected. Moreover, the results emphasize the crucial role of the deposition technique on the features of the sensing layers. Full article
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19 pages, 25262 KiB  
Review
Chiral Recognition with Broad Selective Sensor Arrays
by Gabriele Magna, Manuela Stefanelli, Giuseppe Pomarico, Mario Luigi Naitana, Donato Monti, Corrado Di Natale and Roberto Paolesse
Chemosensors 2022, 10(8), 308; https://doi.org/10.3390/chemosensors10080308 - 04 Aug 2022
Cited by 3 | Viewed by 2130
Abstract
The detection and discrimination of chiral analytes has always been a topical theme in food and pharmaceutical industries and environmental monitoring, especially when dealing with chiral drugs and pesticides, whose enantiomeric nature assessment is of crucial importance. The typical approach matches novel chiral [...] Read more.
The detection and discrimination of chiral analytes has always been a topical theme in food and pharmaceutical industries and environmental monitoring, especially when dealing with chiral drugs and pesticides, whose enantiomeric nature assessment is of crucial importance. The typical approach matches novel chiral receptors designed ad hoc for the discrimination of a target enantiomer with emerging nanotechnologies. The massive synthetic efforts requested and the difficulty of analyzing complex matrices warrant the ever-growing exploitation of sensor array as an alternative route, using a limited number of chiral or both chiral and achiral sensors for the stereoselective identification and dosing of chiral compounds. This review aims to illustrate a little-explored winning strategy in chiral sensing based on sensor arrays. This strategy mimics the functioning of natural olfactory systems that perceive some couples of enantiomeric compounds as distinctive odors (i.e., using an array of a considerable number of broad selective receptors). Thus, fundamental concepts related to the working principle of sensor arrays and the role of data analysis techniques and models have been briefly presented. After the discussion of existing examples in the literature using arrays for discriminating enantiomers and, in some cases, determining the enantiomeric excess, the remaining challenges and future directions are outlined for researchers interested in chiral sensing applications. Full article
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21 pages, 2395 KiB  
Article
Mixed Oxime-Functionalized IL/16-s-16 Gemini Surfactants System: Physicochemical Study and Structural Transitions in the Presence of Promethazine as a Potential Chiral Pollutant
by Subhashree Jayesh Pandya, Illia V. Kapitanov, Manoj Kumar Banjare, Kamalakanta Behera, Victor Borovkov, Kallol K. Ghosh and Yevgen Karpichev
Chemosensors 2022, 10(2), 46; https://doi.org/10.3390/chemosensors10020046 - 25 Jan 2022
Cited by 5 | Viewed by 2509
Abstract
The increasing concern about chiral pharmaceutical pollutants is connected to environmental contamination causing both chronic and acute harmful effects on living organisms. The design and application of sustainable surfactants in the remediation of polluted sites require knowledge of partitioning between surfactants and potential [...] Read more.
The increasing concern about chiral pharmaceutical pollutants is connected to environmental contamination causing both chronic and acute harmful effects on living organisms. The design and application of sustainable surfactants in the remediation of polluted sites require knowledge of partitioning between surfactants and potential pollutants. The interfacial and thermodynamic properties of two gemini surfactants, namely, alkanediyi-α,ω-bis(dimethylhexadecyl ammonium bromide) (16-s-16, where s = 10, 12), were studied in the presence of the inherently biodegradable oxime-functionalized ionic liquid (IL) 4-((hydroxyimino)methyl)-1-(2-(octylamino)-2-oxoethyl)pyridin-1-ium bromide (4-PyC8) in an aqueous solution using surface tension, conductivity, fluorescence, FTIR and 1H NMR spectroscopic techniques. The conductivity, surface tension and fluorescence measurements indicated that the presence of the IL 4-PyC8 resulted in decreasing CMC and facilitated the aggregation process. The various thermodynamic parameters, interfacial properties, aggregation number and Stern–Volmer constant were also evaluated. The IL 4-PyC8-gemini interactions were studied using DLS, FTIR and NMR spectroscopic techniques. The hydrodynamic diameter of the gemini aggregates in the presence of promethazine (PMZ) as a potential chiral pollutant and the IL 4-PyC8 underwent a transition when the drug was added, from large aggregates (270 nm) to small micelles, which supported the gemini:IL 4-PyC8:promethazine interaction. The structural transitions in the presence of promethazine may be used for designing systems that are responsive to changes in size and shape of the aggregates as an analytical signal for selective detection and binding pollutants. Full article
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2021

Jump to: 2023, 2022

23 pages, 5651 KiB  
Review
Advances in Chirality Sensing with Macrocyclic Molecules
by Xiaotong Liang, Wenting Liang, Pengyue Jin, Hongtao Wang, Wanhua Wu and Cheng Yang
Chemosensors 2021, 9(10), 279; https://doi.org/10.3390/chemosensors9100279 - 29 Sep 2021
Cited by 18 | Viewed by 3469
Abstract
The construction of chemical sensors that can distinguish molecular chirality has attracted increasing attention in recent years due to the significance of chiral organic molecules and the importance of detecting their absolute configuration and chiroptical purity. The supramolecular chirality sensing strategy has shown [...] Read more.
The construction of chemical sensors that can distinguish molecular chirality has attracted increasing attention in recent years due to the significance of chiral organic molecules and the importance of detecting their absolute configuration and chiroptical purity. The supramolecular chirality sensing strategy has shown promising potential due to its advantages of high throughput, sensitivity, and fast chirality detection. This review focuses on chirality sensors based on macrocyclic compounds. Macrocyclic chirality sensors usually have inherent complexing ability towards certain chiral guests, which combined with the signal output components, could offer many unique advantages/properties compared to traditional chiral sensors. Chirality sensing based on macrocyclic sensors has shown rapid progress in recent years. This review summarizes recent advances in chirality sensing based on both achiral and chiral macrocyclic compounds, especially newly emerged macrocyclic molecules. Full article
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19 pages, 2860 KiB  
Article
Thiourea Organocatalysts as Emerging Chiral Pollutants: En Route to Porphyrin-Based (Chir)Optical Sensing
by Nele Konrad, Matvey Horetski, Mariliis Sihtmäe, Khai-Nghi Truong, Irina Osadchuk, Tatsiana Burankova, Marc Kielmann, Jasper Adamson, Anne Kahru, Kari Rissanen, Mathias O. Senge, Victor Borovkov, Riina Aav and Dzmitry Kananovich
Chemosensors 2021, 9(10), 278; https://doi.org/10.3390/chemosensors9100278 - 29 Sep 2021
Cited by 4 | Viewed by 3679
Abstract
Environmental pollution with chiral organic compounds is an emerging problem requiring innovative sensing methods. Amino-functionalized thioureas, such as 2-(dimethylamino)cyclohexyl-(3,5-bis(trifluoromethyl)phenyl)thiourea (Takemoto’s catalyst), are widely used organocatalysts with virtually unknown environmental safety data. Ecotoxicity studies based on the Vibrio fischeri luminescence inhibition test reveal significant [...] Read more.
Environmental pollution with chiral organic compounds is an emerging problem requiring innovative sensing methods. Amino-functionalized thioureas, such as 2-(dimethylamino)cyclohexyl-(3,5-bis(trifluoromethyl)phenyl)thiourea (Takemoto’s catalyst), are widely used organocatalysts with virtually unknown environmental safety data. Ecotoxicity studies based on the Vibrio fischeri luminescence inhibition test reveal significant toxicity of Takemoto’s catalyst (EC50 = 7.9 mg/L) and its NH2-substituted analog (EC50 = 7.2–7.4 mg/L). The observed toxic effect was pronounced by the influence of the trifluoromethyl moiety. En route to the porphyrin-based chemosensing of Takemoto-type thioureas, their supramolecular binding to a series of zinc porphyrins was studied with UV-Vis and circular dichroism (CD) spectroscopy, computational analysis and single crystal X-ray diffraction. The association constant values generally increased with the increasing electron-withdrawing properties of the porphyrins and electron-donating ability of the thioureas, a result of the predominant Zn⋯N cation–dipole (Lewis acid–base) interaction. The binding event induced a CD signal in the Soret band region of the porphyrin hosts—a crucial property for chirality sensing of Takemoto-type thioureas. Full article
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17 pages, 4006 KiB  
Review
Estimation of Enantiomeric Excess Based on Rapid Host–Guest Exchange
by Jan Labuta, Shinsuke Ishihara, Daniel T. Payne, Kazuyoshi Takimoto, Hisako Sato, Lenka Hanyková, Katsuhiko Ariga and Jonathan P. Hill
Chemosensors 2021, 9(9), 259; https://doi.org/10.3390/chemosensors9090259 - 09 Sep 2021
Cited by 2 | Viewed by 2524
Abstract
Chiral molecules possess enantiomers that have non-superimposable chemical structures but exhibit identical nuclear magnetic resonance (NMR) spectra. This feature prevents the use of NMR spectroscopic methods for the determination of enantiomeric excesses (ee) of chiral molecules, using simple mixtures of their [...] Read more.
Chiral molecules possess enantiomers that have non-superimposable chemical structures but exhibit identical nuclear magnetic resonance (NMR) spectra. This feature prevents the use of NMR spectroscopic methods for the determination of enantiomeric excesses (ee) of chiral molecules, using simple mixtures of their enantiomers. Recently, however, it was reported that the addition of a symmetrical prochiral molecule (a reporter or host) into a solution of chiral analyte can lead to estimation of ee through interactions involving rapid exchange of the chiral analyte (guest) in the formed host–guest complex. This is due to the ee-dependent splitting of NMR resonances of the prochiral host molecule based on averaging the chemical shift non-equivalency caused by the presence of a chiral guest. The mechanism is not dependent on diastereomer formation, and 1:1 host–guest complexes can also show ee-dependent NMR peak splitting. Prochiral molecules capable of ee sensing using the NMR technique are now referred to as so-called prochiral solvating agents (pro-CSAs). pro-CSAs represent a family of reagents distinct from the commonly used NMR chiral derivatizing reagents (where chiral auxiliaries are used to derivatize enantiomers to diastereomers) or chiral solvating agents (where chiral auxiliaries interact in an asymmetric manner with analyte enantiomers). pro-CSA methods are unique since neither pro-CSA nor NMR contains chiral factors, making the technique neutral with respect to chirality. Here, we review our recent work on this matter involving several different nominally achiral receptor molecules whose unique guest binding properties and solution characteristics (especially with regard to NMR spectroscopy) allow for the estimation of ee in the corresponding chiral guests. Full article
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14 pages, 9110 KiB  
Article
2,12-Diaza[6]helicene: An Efficient Non-Conventional Stereogenic Scaffold for Enantioselective Electrochemical Interphases
by Francesca Fontana, Benedetta Bertolotti, Sara Grecchi, Patrizia Romana Mussini, Laura Micheli, Roberto Cirilli, Matteo Tommasini and Simona Rizzo
Chemosensors 2021, 9(8), 216; https://doi.org/10.3390/chemosensors9080216 - 10 Aug 2021
Cited by 4 | Viewed by 2070
Abstract
The new configurationally stable, unsymmetrical 2,12-diaza[6]helicene was synthesized as a racemate and the enantiomers were separated in an enantiopure state by semi-preparative HPLC on chiral stationary phase. Under selected alkylation conditions it was possible to obtain both the enantiopure 2-N-mono- and [...] Read more.
The new configurationally stable, unsymmetrical 2,12-diaza[6]helicene was synthesized as a racemate and the enantiomers were separated in an enantiopure state by semi-preparative HPLC on chiral stationary phase. Under selected alkylation conditions it was possible to obtain both the enantiopure 2-N-mono- and di-N-ethyl quaternary iodides. Metathesis with bis(trifluoromethanesulfonyl)imide anion gave low-melting salts which were tested as inherently chiral additives to achiral ionic liquids for the electrochemical enantiodiscrimination of chiral organic probes in voltammetric experiments. Remarkable differences in the oxidation potentials of the enantiomers of two probes, a chiral ferrocenyl amine and an aminoacid, were achieved; the differences increase with increasing additive concentration and number of alkylated nitrogen atoms. Full article
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22 pages, 24068 KiB  
Review
Recognition and Sensing of Chiral Organic Molecules by Chiral Porphyrinoids: A Review
by Gabriele Travagliante, Massimiliano Gaeta, Roberto Purrello and Alessandro D’Urso
Chemosensors 2021, 9(8), 204; https://doi.org/10.3390/chemosensors9080204 - 03 Aug 2021
Cited by 8 | Viewed by 3666
Abstract
Porphyrinoids are extremely attractive for their electronic, optical, and coordination properties as well as for their versatile substitution at meso/β-positions. All these features allow porphyrinoids to behave as chiroptical hosts for chiral recognition by means of non-covalent interactions towards chiral guests. Over the [...] Read more.
Porphyrinoids are extremely attractive for their electronic, optical, and coordination properties as well as for their versatile substitution at meso/β-positions. All these features allow porphyrinoids to behave as chiroptical hosts for chiral recognition by means of non-covalent interactions towards chiral guests. Over the years, chiral discrimination of chiral molecules such as amino acids, alcohols, amines, hydroxy-carboxylic acids, etc. has aroused the interest of the scientific community. Hence, this review aims to report on the progress to date by illustrating some relevant research regarding the chiral recognition of a multitude of chiral organic guests through several chiral mono- and bis-porphyrins via different spectroscopic techniques. Full article
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13 pages, 4329 KiB  
Article
Absolute Configuration Sensing of Chiral Aryl- and Aryloxy-Propionic Acids by Biphenyl Chiroptical Probes
by Stefania Vergura, Stefano Orlando, Patrizia Scafato, Sandra Belviso and Stefano Superchi
Chemosensors 2021, 9(7), 154; https://doi.org/10.3390/chemosensors9070154 - 24 Jun 2021
Cited by 5 | Viewed by 1992
Abstract
The absolute configuration of chiral 2-aryl and 2-aryloxy propionic acids, which are among the most common chiral environmental pollutants, has been readily and reliably established by either electronic circular dichroism spectroscopy or optical rotation measurements employing suitably designed 4,4′-disubstituted biphenyl probes. In fact, [...] Read more.
The absolute configuration of chiral 2-aryl and 2-aryloxy propionic acids, which are among the most common chiral environmental pollutants, has been readily and reliably established by either electronic circular dichroism spectroscopy or optical rotation measurements employing suitably designed 4,4′-disubstituted biphenyl probes. In fact, the 4,4′-biphenyl substitution gives rise to a red shift of the diagnostic electronic circular dichroism signal of the biphenyl A band employed for the configuration assignment, removing its overlap with other interfering dichroic bands and allowing its clear sign identification. The largest A band red shift, and thus the most reliable results, are obtained by employing as a probe the 4,4′-dinitro substituted biphenylazepine 3c. The method was applied to the absolute configuration assignment of 2-arylpropionic acids ibuprofen (1a), naproxen (1b), ketoprofen (1c) and flurbiprofen (1d), as well as to the 2-aryloxypropionic acids 2-phenoxypropionic acid (2a) and 2-naphthoxypropionic acid (2b). This approach, allowing us to reveal the sample’s absolute configuration by simple optical rotation measurements, is potentially applicable to online analyses of both the enantiomeric composition and absolute configuration of these chiral pollutants. Full article
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