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22 pages, 1980 KiB

Open AccessReview

Methods of Capture and Transformation of Carbon Dioxide (CO₂) with Macrocycles

by Edilma Sanabria, Mauricio Maldonado, Carlos Matiz, Ana C. F. Ribeiro and Miguel A. Esteso

Processes 2025, 13(1), 117; https://doi.org/10.3390/pr13010117 - 4 Jan 2025

Cited by 2 | Viewed by 2024

Rapid industrialization and the indiscriminate use of fossil fuels have generated an impact that is affecting the climate worldwide. Among the substances that are causing climate change are several gases such as carbon dioxide (CO₂), methane (CH₄), nitrous oxide [...] Read more.

Rapid industrialization and the indiscriminate use of fossil fuels have generated an impact that is affecting the climate worldwide. Among the substances that are causing climate change are several gases such as carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O) and sulphur hexafluoride (SF₆), among others. Particularly, carbon dioxide is one of the substances that has attracted the most attention from researchers, as it is responsible for more than three quarters of greenhouse gases. Because of this, many efforts have been directed towards the capture of CO₂, its separation, adsorption and transformation into products that are less harmful to the environment or that even have added value in the industry. For this purpose, the use of different types of macrocycles has been explored mainly in the last 5 years. This review seeks to present the advances that have occurred in recent years in the capture and transformation of CO₂ by different methods, to finally focus on the capture and transformation through macrocycle systems such as azacompounds, heterometallic macrocycles, calixpyrrols, modified cyclodextrins and metallic porphyrins, among others. Full article

(This article belongs to the Section Environmental and Green Processes)

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22 pages, 9994 KiB

Open AccessReview

Recent Advances in Synthesis and Applications of Calixarene Derivatives Endowed with Anticancer Activity

by Elżbieta Wojaczyńska, Marta Ostrowska, Małgorzata Lower, Natalia Czyżyk, Anna Jakieła and Alberto Marra

Molecules 2024, 29(17), 4240; https://doi.org/10.3390/molecules29174240 - 6 Sep 2024

Cited by 2 | Viewed by 2412

Abstract

Calix[n]arenes, macrocycles constituted of 4–8 phenol moieties linked through methylene bridges, are stable molecules that can be selectively functionalised at the upper or lower rim. It has already been demonstrated that calixarene derivatives can be biologically or pharmacologically active compounds. More recently, suitably [...] Read more.

Calix[n]arenes, macrocycles constituted of 4–8 phenol moieties linked through methylene bridges, are stable molecules that can be selectively functionalised at the upper or lower rim. It has already been demonstrated that calixarene derivatives can be biologically or pharmacologically active compounds. More recently, suitably functionalised calixarenes and calixarene analogues (dihomooxacalixarenes, thiacalixarenes, calix[4]resorcinols, azacalixarenes, calixpyrroles, and pillarenes) were found to act as anticancer agents, at least in in vitro assays. We are reporting on the latest progress in this research field. Full article

(This article belongs to the Section Bioorganic Chemistry)

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15 pages, 3753 KiB

Open AccessArticle

Removal of Methylene Blue Dye from Aqueous Solutions Using Polymer Inclusion Membrane Containing Calix[4]pyrrole

by Anna Nowik-Zajac, Iwona Zawierucha, Jakub Lagiewka, Karolina Jaksender, Katarzyna Witt, Grzegorz Malina and Vira Sabadash

Membranes 2024, 14(4), 92; https://doi.org/10.3390/membranes14040092 - 17 Apr 2024

Cited by 8 | Viewed by 2587

Abstract

The effective purification of aqueous solutions of methylene blue dye was tested using polymer inclusion membranes (PIMs) that contained cellulose triacetate (CTA) as a polymer base, o-nitrophenyl octyl ether (o-NPOE) as a plasticizer, and meso-tetra methyl tetrakis-[methyl-2-(4-acetlphenoxy)] calix[4]pyrrole (KP) as [...] Read more.

The effective purification of aqueous solutions of methylene blue dye was tested using polymer inclusion membranes (PIMs) that contained cellulose triacetate (CTA) as a polymer base, o-nitrophenyl octyl ether (o-NPOE) as a plasticizer, and meso-tetra methyl tetrakis-[methyl-2-(4-acetlphenoxy)] calix[4]pyrrole (KP) as a carrier. Scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy were used to define the microstructure and surface of PIMs. Experimental results showed that, with an increased concentration of methylene blue in an aqueous solution, the removal percentage also increased. Further observation showed that the flux increased with the rise in the source phase pH values from 3 to 10. The carrier and plasticizer content in the membrane significantly influenced the membrane’s transport properties. The optimal composition of the membrane in percent by weight for KP was 74% plasticizer; 18% support, and 8% carrier. The maximum MB removal (93.10%) was achieved at 0.10 M HCl solution as the receiving phase. It was shown that the membrane with optimal composition showed good reusability and enabled the easy and spontaneous separation of methylene blue from aqueous solutions. Full article

(This article belongs to the Collection Polymeric Membranes: Science, Materials and Applications)

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17 pages, 1994 KiB

Open AccessArticle

Tetrapodal Anion Transporters

by Alexander M. Gilchrist, Lijun Chen, Xin Wu, William Lewis, Ethan N.W. Howe, Lauren K. Macreadie and Philip A. Gale

Molecules 2020, 25(21), 5179; https://doi.org/10.3390/molecules25215179 - 6 Nov 2020

Cited by 8 | Viewed by 3889

Abstract

Synthetic anion transporters that facilitate chloride transport are promising candidates for channelopathy treatments. However, most anion transporters exhibit an undesired side effect of facilitating proton transport via interacting with fatty acids present in the membrane. To address the limitation, we here report the [...] Read more.

Synthetic anion transporters that facilitate chloride transport are promising candidates for channelopathy treatments. However, most anion transporters exhibit an undesired side effect of facilitating proton transport via interacting with fatty acids present in the membrane. To address the limitation, we here report the use of a new tetrapodal scaffold to maximize the selective interaction with spherical chloride over binding the carboxylate headgroup of fatty acids. One of the new transporters demonstrated a high selectivity for chloride uniport over fatty acid-induced proton transport while being >10 times more active in chloride uniport than strapped calixpyrroles that were previously the only class of compounds known to possess similar selectivity properties. Full article

(This article belongs to the Special Issue Supramolecular Anion Binding and Molecular Recognition)

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21 pages, 6065 KiB

Open AccessReview

Macrocycles and Supramolecules as Antioxidants: Excellent Scaffolds for Development of Potential Therapeutic Agents

by Jung-Seop Lee, In-ho Song, Pramod B. Shinde and Satish Balasaheb Nimse

Antioxidants 2020, 9(9), 859; https://doi.org/10.3390/antiox9090859 - 14 Sep 2020

Cited by 21 | Viewed by 4306

Abstract

Oxidative stress due to the high levels of reactive oxygen species (ROS) that damage biomolecules (lipids, proteins, DNA) results in acute inflammation. However, without proper intervention, acute inflammation progresses to chronic inflammation and then to several chronic diseases, including cancer, myocardial infarction, cardiovascular [...] Read more.

Oxidative stress due to the high levels of reactive oxygen species (ROS) that damage biomolecules (lipids, proteins, DNA) results in acute inflammation. However, without proper intervention, acute inflammation progresses to chronic inflammation and then to several chronic diseases, including cancer, myocardial infarction, cardiovascular diseases, chronic inflammation, atherosclerosis, and more. There has been extensive research on the antioxidants of natural origin. However, there are myriad possibilities for the development of synthetic antioxidants for pharmacological applications. There is an increasing interest in the identification of novel synthetic antioxidants for the modulation of biochemical processes related to ROS. In this regard, derivatives of supramolecules, such as calix[n]arene, resorcinarene, calixtyrosol, calixpyrrole, cucurbit[n]uril, porphyrin etc. are gaining attention for their abilities to scavenge the free radicals. Supramolecular chemistry offers excellent scaffolds for the development of novel antioxidants that can be used to modulate free radical reactions and to improve the disorders related to oxidative stress. This review focuses on the interdisciplinary approach for the design and development of novel synthetic antioxidants based on supramolecular scaffolds, with potentially protective effects against oxidative stress. Full article

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16 pages, 2634 KiB

Open AccessArticle

Selective Transport of Ag(I) through a Polymer Inclusion Membrane Containing a Calix[4]pyrrole Derivative from Nitrate Aqueous Solutions

by Anna Nowik-Zajac, Iwona Zawierucha and Cezary Kozlowski

Int. J. Mol. Sci. 2020, 21(15), 5348; https://doi.org/10.3390/ijms21155348 - 28 Jul 2020

Cited by 21 | Viewed by 2691

Abstract

Cellulose-triacetate-based polymer inclusion membranes (PIMs) with different concentrations of a calixpyrrole ester derivative as the membrane carrier were studied to determine their ability to transport Ag(I) from aqueous nitrate solutions. The effects of the concentrations of ion carriers and metal ions, the pH [...] Read more.

Cellulose-triacetate-based polymer inclusion membranes (PIMs) with different concentrations of a calixpyrrole ester derivative as the membrane carrier were studied to determine their ability to transport Ag(I) from aqueous nitrate solutions. The effects of the concentrations of ion carriers and metal ions, the pH of the source aqueous phase, and stripping agents on the effective transport of Ag(I) were assessed. All studied parameters were found to be important factors for the transport of Ag(I) metal ions. The initial fluxes were determined at different temperatures. The prepared membranes were found to be highly permeable. The selectivity of silver transport from an aqueous solution containing Ag(I), Cu(II), Pb(II), Cd(II), Ni(II), Zn(II), and Co(II) ions was also investigated. Full article

(This article belongs to the Special Issue Ion and Molecule Transport in Membrane Systems 2.0)

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11 pages, 1250 KiB

Open AccessArticle

Isotopic Labeling Study of the Formation of Calix[5]pyrroles Catalyzed by Bi(NO₃)₃

by Luis Chacón-García, Claudia A. Contreras-Celedón and Melissa Tapia-Juárez

Catalysts 2013, 3(3), 588-598; https://doi.org/10.3390/catal3030588 - 8 Jul 2013

Cited by 3 | Viewed by 9124

Abstract

One of the more elusive classes of macrocycles includes the calix[5]pyrroles, which can be obtained from pyrrole and acetone in the presence of low concentrations of Bi(NO₃)₃-5H₂O. An isotopic labeling experiment aided the proposal of a mechanism [...] Read more.

One of the more elusive classes of macrocycles includes the calix[5]pyrroles, which can be obtained from pyrrole and acetone in the presence of low concentrations of Bi(NO₃)₃-5H₂O. An isotopic labeling experiment aided the proposal of a mechanism to explain the formation of calix[5]pyrrole at low acid concentrations and the exclusive formation of calix[4]pyrrole at high acid concentrations. We assume that the mechanism involves HNO₃, which is released from the Bi salt. Full article

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8 pages, 156 KiB

Open AccessArticle

Calixpyrrole Derivatives: “Multi Hydrogen Bond” Catalysts for γ-Butenolide Synthesis

by Grazia Cafeo, Margherita De Rosa, Franz H. Kohnke, Annunziata Soriente, Carmen Talotta and Luca Valenti

Molecules 2009, 14(7), 2594-2601; https://doi.org/10.3390/molecules14072594 - 15 Jul 2009

Cited by 27 | Viewed by 14422

Abstract

Calix[4]pyrrole (1), calix[2]m-benzo[4]pyrrole (2), 10α,20β- and 10α,20α- bis(4-nitrophenyl)-calix[4]pyrroles 3 and 4, respectively, were found to exhibit various organocatalytic activities in the diastereoselective vinylogous addition reaction of 2-trimethylsilyloxyfuran (TMSOF, 7) to aldehydes. The γ-hydroxybutenolide products are obtained in fairly good yields and [...] Read more.

Calix[4]pyrrole (1), calix[2]m-benzo[4]pyrrole (2), 10α,20β- and 10α,20α- bis(4-nitrophenyl)-calix[4]pyrroles 3 and 4, respectively, were found to exhibit various organocatalytic activities in the diastereoselective vinylogous addition reaction of 2-trimethylsilyloxyfuran (TMSOF, 7) to aldehydes. The γ-hydroxybutenolide products are obtained in fairly good yields and with moderate diastereoselectivity. The structures of the catalysts, as well as the reaction conditions, strongly influence the efficiency of the reaction. Full article

(This article belongs to the Special Issue Organocatalysis)

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