Pamela Mendioroz, Andrés I. Casoni, María A. Volpe, Darío C. Gerbino
The transition from traditional stoichiometric methods to catalytic processes has significantly advanced the synthesis of xanthones, privileged structures with diverse biological activities. This review critically examines various homogeneous and heterogeneous catalytic methodologies, emphasising their efficiency, and adherence to green chemistry principles. Through comparative analysis of key metrics such as Reaction Mass Efficiency (RME), Process Mass Intensity (PMI), E‐factor, and Turnover Number (TON), we highlight the superior performance of heterogeneous catalysts, which demonstrate high reusability, selectivity, and minimal waste generation. The choice of solvent, a crucial factor in the environmental footprint of these processes, is also assessed, focusing on greener alternatives. The robust nature and economic viability of heterogeneous catalysts make them ideal for large‐scale applications, offering suitable solutions for more environmentally‐friendly xanthone production. Furthermore, the reduction in byproducts and the importance of catalyst purity in pharmaceutical applications are discussed, underscoring the relevance of these advancements in meeting the rigorous standards of the industry. This review provides valuable insights into the ongoing evolution of catalytic strategies in xanthone synthesis, driving future developments in medicinal chemistry and green chemistry.
{"title":"Xanthone Synthesis through Catalysis: Exploring the Green Limits of Homogeneous and Heterogeneous Methods","authors":"Pamela Mendioroz, Andrés I. Casoni, María A. Volpe, Darío C. Gerbino","doi":"10.1002/ejoc.202401027","DOIUrl":"https://doi.org/10.1002/ejoc.202401027","url":null,"abstract":"The transition from traditional stoichiometric methods to catalytic processes has significantly advanced the synthesis of xanthones, privileged structures with diverse biological activities. This review critically examines various homogeneous and heterogeneous catalytic methodologies, emphasising their efficiency, and adherence to green chemistry principles. Through comparative analysis of key metrics such as Reaction Mass Efficiency (RME), Process Mass Intensity (PMI), E‐factor, and Turnover Number (TON), we highlight the superior performance of heterogeneous catalysts, which demonstrate high reusability, selectivity, and minimal waste generation. The choice of solvent, a crucial factor in the environmental footprint of these processes, is also assessed, focusing on greener alternatives. The robust nature and economic viability of heterogeneous catalysts make them ideal for large‐scale applications, offering suitable solutions for more environmentally‐friendly xanthone production. Furthermore, the reduction in byproducts and the importance of catalyst purity in pharmaceutical applications are discussed, underscoring the relevance of these advancements in meeting the rigorous standards of the industry. This review provides valuable insights into the ongoing evolution of catalytic strategies in xanthone synthesis, driving future developments in medicinal chemistry and green chemistry.","PeriodicalId":167,"journal":{"name":"European Journal of Organic Chemistry","volume":"123 1 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Américo J. S. Alves, João A. D. Silvestre, Teresa M. V. D. Pinho e Melo
The Front Cover illustrates the development of continuous flow spirocyclization of 6-alkylidenepenicillanates leading to chiral spiro-β-lactams through phosphine-catalyzed [3+2] annulation of allenoates and 1,3-dipolar cycloaddition with diphenyldiazomethane. The continuous-flow synthesis of spirocyclopropanepenicillanates through thermal ring contraction of spiro-1-pyrazolinepenicillanates was also included in the study. The reported methodology is a more sustainable approach for the scale-up production of compounds with significant biological properties in high yields. More information can be found in the Research Article by T. M. V. D. Pinho e Melo and co-workers (DOI: 10.1002/ejoc.202400689).
封面展示了 6-亚烷基青霉烷酸酯的连续流螺环化技术的发展，该技术通过磷化氢催化异烯酸酯的[3+2]环化反应以及与二苯基二氮甲烷的 1,3-二极环加成反应生成手性螺-β-内酰胺。该研究还包括通过螺-1-吡唑啉青霉烷酸酯的热环收缩连续流合成螺环丙青霉烷酸酯。所报告的方法是一种更可持续的方法，可用于扩大高产率生产具有重要生物特性的化合物。更多信息，请参阅 T. M. V. 的研究文章。V.D.Pinho e Melo 及其合作者的研究文章中（DOI: 10.1002/ejoc.202400689）。
{"title":"Front Cover: Continuous Flow Spirocyclization Reactions: Towards Efficient Synthesis of Chiral Spiropenicillanates (Eur. J. Org. Chem. 42/2024)","authors":"Américo J. S. Alves, João A. D. Silvestre, Teresa M. V. D. Pinho e Melo","doi":"10.1002/ejoc.202484201","DOIUrl":"10.1002/ejoc.202484201","url":null,"abstract":"<p><b>The Front Cover</b> illustrates the development of continuous flow spirocyclization of 6-alkylidenepenicillanates leading to chiral spiro-β-lactams through phosphine-catalyzed [3+2] annulation of allenoates and 1,3-dipolar cycloaddition with diphenyldiazomethane. The continuous-flow synthesis of spirocyclopropanepenicillanates through thermal ring contraction of <i>spiro</i>-1-pyrazolinepenicillanates was also included in the study. The reported methodology is a more sustainable approach for the scale-up production of compounds with significant biological properties in high yields. More information can be found in the Research Article by T. M. V. D. Pinho e Melo and co-workers (DOI: 10.1002/ejoc.202400689).\u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure>\u0000 </p>","PeriodicalId":167,"journal":{"name":"European Journal of Organic Chemistry","volume":"27 42","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ejoc.202484201","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142637211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sodium oligomannate, a sophisticated mixture of acidic linear β‐(1,4)‐d‐oligomannurarate ranging from dimers to decamers with an average molecular weight of 670∼880 Da, has gained conditional approval for the treatment of Alzheimer's disease. Herein, we develop an efficient approach to the chemical synthesis of well‐defined β‐(1,4)‐d‐mannurarate di‐, tetra‐, hexa‐ and octasaccharides (1‐4), utilizing N‐phenyl trifluoroacetimidate donors and thioglycoside acceptors for the stereoselective assembly of the desired β‐(1,4)‐d‐mannuronate linkages. This approach features a straightforward protecting group strategy with only two types of protecting groups: tert‐butyldimethylsilyl (TBS) for the 4‐OH at the non‐reducing end and benzyl (Bn) for free hydroxyl and carboxylic acid moieties, thereby ensuring the stereoselective formation of the β‐mannosyl bonds and facilitating sequential transformation into the target β‐(1,4)‐d‐mannurarate oligosaccharides. The scalability of the present synthesis of these oligosaccharides paves the way for in‐depth structure‐activity relationship studies and pharmacological investigations of sodium oligomannates.
{"title":"Chemical Synthesis of β‐(1,4)‐d‐Oligomannurarates with Purported Anti‐Alzheimer Activity","authors":"Peng Xu, Xiaofei Shao, Biao Yu","doi":"10.1002/ejoc.202401125","DOIUrl":"https://doi.org/10.1002/ejoc.202401125","url":null,"abstract":"Sodium oligomannate, a sophisticated mixture of acidic linear β‐(1,4)‐d‐oligomannurarate ranging from dimers to decamers with an average molecular weight of 670∼880 Da, has gained conditional approval for the treatment of Alzheimer's disease. Herein, we develop an efficient approach to the chemical synthesis of well‐defined β‐(1,4)‐d‐mannurarate di‐, tetra‐, hexa‐ and octasaccharides (1‐4), utilizing N‐phenyl trifluoroacetimidate donors and thioglycoside acceptors for the stereoselective assembly of the desired β‐(1,4)‐d‐mannuronate linkages. This approach features a straightforward protecting group strategy with only two types of protecting groups: tert‐butyldimethylsilyl (TBS) for the 4‐OH at the non‐reducing end and benzyl (Bn) for free hydroxyl and carboxylic acid moieties, thereby ensuring the stereoselective formation of the β‐mannosyl bonds and facilitating sequential transformation into the target β‐(1,4)‐d‐mannurarate oligosaccharides. The scalability of the present synthesis of these oligosaccharides paves the way for in‐depth structure‐activity relationship studies and pharmacological investigations of sodium oligomannates.","PeriodicalId":167,"journal":{"name":"European Journal of Organic Chemistry","volume":"42 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142599078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Martin Huber, Matthias Schöbinger, Jordi Cirera, Berthold Stöger, Peter Weinberger
Four novel fluorescence active ligands (1-4) consisting of a 1H-tetrazol-1-yl moiety as coordinating unit and a 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) derivative as fluorophore, bridged via alkyl (-(CH2)n-, n = 1‑3) or benzyl (-CH2-C6H4-) spacers were designed. Successful synthesis is demonstrated by multinuclear NMR spectroscopy, as well as powder and single crystal XRD analysis. The methylene bridged ligand 2 (4,4-difluoro-1,3,5,7-tetramethyl-8-[(1H-tetrazol-1-yl)methyl]-4-bora-3a,4a-diaza-s-indacene) crystallizes in different polymorphs and solvatomorphs, in contrast to the other three ligands, which show no polymorphism under identical conditions. Photophysical studies revealed high fluorescence quantum yields (69 – 95%) in solution for the -(CH2)2- bridged ligand 3 (4,4-difluoro-1,3,5,7-tetramethyl-8-[(1H-tetrazol-1-yl)ethyl]-4-bora-3a,4a-diaza-s-indacene) and the -(CH2)3- bridged ligand 4 (4,4-difluoro-1,3,5,7-tetramethyl-8-[(1H-tetrazol-1-yl)propyl]-4-bora-3a,4a-diaza-s-indacene). Non-radiative decay due to rotational motion of the 1H-tetrazol-1-yl- and/or -CH2-C6H4- moiety for 2 and 1 (4,4-difluoro-1,3,5,7-tetramethyl-8-[4-((1H-tetrazol-1-yl)methyl)phenyl]-4-bora-3a,4a-diaza-s-indacene) respectively leads to reduced quantum yields of ≥ 35%. Complete fluorescence quenching upon aggregation is prevented by installation of the sterically demanding 1H-tetrazol-1-yl moiety and a spacer in meso-position of the BODIPY core to elongate the intermolecular distances between two adjacent BODIPY cores. Detailed photophysical and crystallographic investigations are supported by theoretical calculations.
{"title":"Design, Synthesis and Characterization of BODIPY based 1H-Tetrazole Ligands","authors":"Martin Huber, Matthias Schöbinger, Jordi Cirera, Berthold Stöger, Peter Weinberger","doi":"10.1002/ejoc.202401239","DOIUrl":"https://doi.org/10.1002/ejoc.202401239","url":null,"abstract":"Four novel fluorescence active ligands (1-4) consisting of a 1H-tetrazol-1-yl moiety as coordinating unit and a 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) derivative as fluorophore, bridged via alkyl (-(CH2)n-, n = 1‑3) or benzyl (-CH2-C6H4-) spacers were designed. Successful synthesis is demonstrated by multinuclear NMR spectroscopy, as well as powder and single crystal XRD analysis. The methylene bridged ligand 2 (4,4-difluoro-1,3,5,7-tetramethyl-8-[(1H-tetrazol-1-yl)methyl]-4-bora-3a,4a-diaza-s-indacene) crystallizes in different polymorphs and solvatomorphs, in contrast to the other three ligands, which show no polymorphism under identical conditions. Photophysical studies revealed high fluorescence quantum yields (69 – 95%) in solution for the -(CH2)2- bridged ligand 3 (4,4-difluoro-1,3,5,7-tetramethyl-8-[(1H-tetrazol-1-yl)ethyl]-4-bora-3a,4a-diaza-s-indacene) and the -(CH2)3- bridged ligand 4 (4,4-difluoro-1,3,5,7-tetramethyl-8-[(1H-tetrazol-1-yl)propyl]-4-bora-3a,4a-diaza-s-indacene). Non-radiative decay due to rotational motion of the 1H-tetrazol-1-yl- and/or -CH2-C6H4- moiety for 2 and 1 (4,4-difluoro-1,3,5,7-tetramethyl-8-[4-((1H-tetrazol-1-yl)methyl)phenyl]-4-bora-3a,4a-diaza-s-indacene) respectively leads to reduced quantum yields of ≥ 35%. Complete fluorescence quenching upon aggregation is prevented by installation of the sterically demanding 1H-tetrazol-1-yl moiety and a spacer in meso-position of the BODIPY core to elongate the intermolecular distances between two adjacent BODIPY cores. Detailed photophysical and crystallographic investigations are supported by theoretical calculations.","PeriodicalId":167,"journal":{"name":"European Journal of Organic Chemistry","volume":"2021 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142600045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jen-Chieh Hsieh, Vijaykumar H. Thorat, Hao-Yu Chao, Po-Han Yang
Herein, we report an efficient scandium‐catalytic reaction protocol for the classical Fischer indole synthesis, which can tolerate a wide variety of polycyclic substrates and allow us to easily construct complex indole structures in high yields for most cases. Moreover, in order to demonstrate the reaction efficacy, we also synthesized two quinazolinone‐containing natural alkaloids, their analog, as well as an anticancer indenoindolone compound.
{"title":"Scandium‐Catalyzed Fischer Indole Synthesis: A Highly Efficient Construction of Complicated Indoles","authors":"Jen-Chieh Hsieh, Vijaykumar H. Thorat, Hao-Yu Chao, Po-Han Yang","doi":"10.1002/ejoc.202401194","DOIUrl":"https://doi.org/10.1002/ejoc.202401194","url":null,"abstract":"Herein, we report an efficient scandium‐catalytic reaction protocol for the classical Fischer indole synthesis, which can tolerate a wide variety of polycyclic substrates and allow us to easily construct complex indole structures in high yields for most cases. Moreover, in order to demonstrate the reaction efficacy, we also synthesized two quinazolinone‐containing natural alkaloids, their analog, as well as an anticancer indenoindolone compound.","PeriodicalId":167,"journal":{"name":"European Journal of Organic Chemistry","volume":"95 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142599080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nikos Siakavaras, Michael G. Kallitsakis, Evangelos G. Bakalbassis, Michael M. Sigalas, Ioannis N. Lykakis
The Front Cover shows methanolic media as a vehicle for a green, one-pot and metal-free synthetic approach to 5- and 6-membered N-heterocycle clusters, starting with benzonitriles and different available diamines and amino alcohols. The dual role of methanol as solvent and as mediated agent is supported by mechanistic and theoretical studies. More information can be found in the Research Article by I. N. Lykakis and co-workers (DOI: 10.1002/ejoc.202400601).
封面展示了甲醇介质作为一种绿色、一锅式和无金属合成 5 元和 6 元 N-heterocycle 簇的载体，以苯腈和不同的二元胺和氨基醇为起点。机理和理论研究证实了甲醇作为溶剂和介导剂的双重作用。更多信息可参见 I. N. Lykakis 及其合作者的研究文章。Lykakis 及其合作者的研究文章中（DOI: 10.1002/ejoc.202400601）。
{"title":"Front Cover: Methanol-Mediated One-Pot Transformation of Benzonitriles to Five and Six-Membered Heterocycles: Synthesis and Mechanistic Approach (Eur. J. Org. Chem. 41/2024)","authors":"Nikos Siakavaras, Michael G. Kallitsakis, Evangelos G. Bakalbassis, Michael M. Sigalas, Ioannis N. Lykakis","doi":"10.1002/ejoc.202484101","DOIUrl":"10.1002/ejoc.202484101","url":null,"abstract":"<p><b>The Front Cover</b> shows methanolic media as a vehicle for a green, one-pot and metal-free synthetic approach to 5- and 6-membered N-heterocycle clusters, starting with benzonitriles and different available diamines and amino alcohols. The dual role of methanol as solvent and as mediated agent is supported by mechanistic and theoretical studies. More information can be found in the Research Article by I. N. Lykakis and co-workers (DOI: 10.1002/ejoc.202400601).\u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure>\u0000 </p>","PeriodicalId":167,"journal":{"name":"European Journal of Organic Chemistry","volume":"27 41","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ejoc.202484101","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142599129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elena Badetti , Vega Lloveras , Melvin Raulin , Francesca A. Scaramuzzo , Jaume Veciana , José Vidal‐Gancedo , Giulia Licini , Cristiano Zonta
A new family of stable radical‐containing polytopic ligands based on tris(2‐pyridylmethyl)amines TPMA architecture and their corresponding metal complexes have been synthesized. These molecular systems offered the possibility to investigate how various spin carriers, such as the metal ion and the organic radical, influence their EPR properties mainly through the empirical ratio of peak heights d1/d. Moreover, it has been possible to analyze how different conformations of TEMPO radical units in the molecular skeleton affect the metallic system.
我们合成了基于三（2-吡啶基甲基）胺 TPMA 结构的一系列新的稳定的含自由基多位配体及其相应的金属配合物。这些分子体系为研究金属离子和有机自由基等各种自旋载体如何主要通过峰高 d1/d 的经验比来影响其 EPR 特性提供了可能。此外，还可以分析分子骨架中 TEMPO 自由基单元的不同构象如何影响金属体系。
{"title":"Synthesis and EPR Studies of Zinc and Copper Tris(2‐pyridylmethyl)amines (TPMA) Metal Complexes Containing TEMPO Functionalities","authors":"Elena Badetti , Vega Lloveras , Melvin Raulin , Francesca A. Scaramuzzo , Jaume Veciana , José Vidal‐Gancedo , Giulia Licini , Cristiano Zonta","doi":"10.1002/ejoc.202400384","DOIUrl":"10.1002/ejoc.202400384","url":null,"abstract":"<div><div>A new family of stable radical‐containing polytopic ligands based on tris(2‐pyridylmethyl)amines TPMA architecture and their corresponding metal complexes have been synthesized. These molecular systems offered the possibility to investigate how various spin carriers, such as the metal ion and the organic radical, influence their EPR properties mainly through the empirical ratio of peak heights <em>d<sub>1</sub>/d</em>. Moreover, it has been possible to analyze how different conformations of TEMPO radical units in the molecular skeleton affect the metallic system.</div></div>","PeriodicalId":167,"journal":{"name":"European Journal of Organic Chemistry","volume":"27 42","pages":"Article e202400384"},"PeriodicalIF":2.5,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lavina Gladis Serrao, S. Naveenkumar, Mahagundappa R. Maddani
Cu(OTf)2 catalysed 1,6‐addition and oxidative C−H functionalization of p‐quinone methides with sydnones is developed. Diversely substituted triarylmethanes and quinones have been synthesized in good to excellent yields in short reaction time. Further, the antioxidant activity of some of the synthesised triarylmethanes was investigated using DPPH assay and the compounds show good antioxidant property.
{"title":"Addition of Sydnones to para‐Quinone Methides: Selective 1,6‐Additions and Oxidative C−H Functionalizations","authors":"Lavina Gladis Serrao, S. Naveenkumar, Mahagundappa R. Maddani","doi":"10.1002/ejoc.202400703","DOIUrl":"https://doi.org/10.1002/ejoc.202400703","url":null,"abstract":"Cu(OTf)<jats:sub>2</jats:sub> catalysed 1,6‐addition and oxidative C−H functionalization of <jats:italic>p</jats:italic>‐quinone methides with sydnones is developed. Diversely substituted triarylmethanes and quinones have been synthesized in good to excellent yields in short reaction time. Further, the antioxidant activity of some of the synthesised triarylmethanes was investigated using DPPH assay and the compounds show good antioxidant property.","PeriodicalId":167,"journal":{"name":"European Journal of Organic Chemistry","volume":"13 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142599130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rukiya Matsidik, Hartmut Komber, Paul Burkhard, Daniel Beer, Carsten Deibel, Michael Sommer
Oligomeric materials combine advantageous properties of both their small molecule and polymeric counterparts. Utilizing oligomers as non‐fullerene acceptors (NFAs) has been shown to be extremely useful for the development of organic solar cells with high efficiency, reproducible performance and long‐term stability. Here we report on two series of synthetically simple acceptor‐terminated oligomers A−T2‐(NDI−T2)n‐A with naphthalene diimide (NDI) and bithiophene (T2) cores up to the trimer (n =1,2,3). Termination of the oligomers is done using the strong acceptors (A) dicyanomethylene‐indanone (IC) and rhodanine (RD). Upon acceptor termination in the presence of piperidine (pip) as base, oligomers with pip‐substituted tricyclic end groups are obtained in high yield. We investigate the effect of oligomer length and acceptor end group on opto‐electronic properties and crystallinity. Both IC‐ and RD‐termination increase electron affinity compared to the parent, non‐functionalized cores. UV‐vis absorption in solution slightly redshifts as the chain length increases without showing a distinct aggregation. Asymmetric termination with hexylphenyl‐substituted indacenodithiophene (IDT) and IC is also possible. All symmetric oligomers show a strong tendency for crystallization, with the oligomer having the tricyclic end group exhibiting the highest melting enthalpy and temperature. The asymmetric IDT−T2‐NDI−T2‐IC oligomer is amorphous.
{"title":"Acceptor End‐functionalization of Naphthalenediimide Bithiophene Oligomers","authors":"Rukiya Matsidik, Hartmut Komber, Paul Burkhard, Daniel Beer, Carsten Deibel, Michael Sommer","doi":"10.1002/ejoc.202400751","DOIUrl":"https://doi.org/10.1002/ejoc.202400751","url":null,"abstract":"Oligomeric materials combine advantageous properties of both their small molecule and polymeric counterparts. Utilizing oligomers as non‐fullerene acceptors (NFAs) has been shown to be extremely useful for the development of organic solar cells with high efficiency, reproducible performance and long‐term stability. Here we report on two series of synthetically simple acceptor‐terminated oligomers A−T2‐(NDI−T2)<jats:sub>n</jats:sub>‐A with naphthalene diimide (NDI) and bithiophene (T2) cores up to the trimer (n =1,2,3). Termination of the oligomers is done using the strong acceptors (A) dicyanomethylene‐indanone (IC) and rhodanine (RD). Upon acceptor termination in the presence of piperidine (pip) as base, oligomers with pip‐substituted tricyclic end groups are obtained in high yield. We investigate the effect of oligomer length and acceptor end group on opto‐electronic properties and crystallinity. Both IC‐ and RD‐termination increase electron affinity compared to the parent, non‐functionalized cores. UV‐vis absorption in solution slightly redshifts as the chain length increases without showing a distinct aggregation. Asymmetric termination with hexylphenyl‐substituted indacenodithiophene (IDT) and IC is also possible. All symmetric oligomers show a strong tendency for crystallization, with the oligomer having the tricyclic end group exhibiting the highest melting enthalpy and temperature. The asymmetric IDT−T2‐NDI−T2‐IC oligomer is amorphous.","PeriodicalId":167,"journal":{"name":"European Journal of Organic Chemistry","volume":"21 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142596778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The non‐covalent interactions in molecules play important roles towards their applications in various aspects such as molecular recognition, catalysis, supramolecular chemistry, structural biology, pharmacology etc. Interestingly, among various non‐bonding interactions, chalcogen bonding (ChB) has been extensively studied in different facets of crystal engineering over the last several years. The present study demonstrates the presence of Se···N or Se···Se ChB in the benzimidazole‐fused cyclic selenazonium selenocyanates (6‐8), cyclic selenazinium selenocyanates (9‐10) and the acyclic benzimidazolium analogs having two different types of selenocyanate units (11‐12). The final organoselenium compounds were synthesized from benzimidazole in several steps in reasonably good yields. The single crystal X‐ray structures of the compounds revealed that both the N atom and Se atom of the negatively charged SeCN unit act as ChB acceptors in building the Se···N or Se···Se ChB interactions along with the additional hydrogen bonding (HB) interactions. Moreover, the structural optimization and natural bond orbital (NBO) analyses were carried out using density functional theory (DFT) to calculate the natural charges on different Se centers and the strength of second‐order perturbation energy (E2) for the ChB interactions. Finally, electrostatic potential surface (SEP) of the compounds was developed to visualize the formation of σ‐holes.
分子中的非共价相互作用在分子识别、催化、超分子化学、结构生物学、药理学等各方面的应用中发挥着重要作用。有趣的是，在各种非键相互作用中，钙原键（ChB）在过去几年中已在晶体工程的不同方面得到广泛研究。本研究表明，在苯并咪唑融合环硒唑硒氰酸酯（6-8）、环硒嗪硒氰酸酯（9-10）和具有两种不同类型硒氰酸酯单元的无环苯并咪唑类似物（11-12）中存在 Se-N 或 Se-Se ChB。最终的有机硒化合物是由苯并咪唑经过几个步骤合成的，收率相当高。这些化合物的单晶 X 射线结构显示，带负电荷的 SeCN 单元中的 N 原子和 Se 原子在建立 Se-N 或 Se-Se ChB 相互作用以及额外的氢键 (HB) 相互作用时都是 ChB 受体。此外，还利用密度泛函理论（DFT）进行了结构优化和天然键轨道（NBO）分析，以计算不同 Se 中心的天然电荷和 ChB 相互作用的二阶扰动能（E2）强度。最后，还开发了化合物的静电位面 (SEP)，以观察σ孔的形成。
{"title":"Structurally Innovative Benzimidazole‐fused Ionic Organoselenium Compounds: Prevalence of Se···N/Se Chalcogen Bonds with the Selenocyanate Receptor","authors":"Krishna Pada Bhabak, Kaustav Banerjee, Abu Sufian","doi":"10.1002/ejoc.202401245","DOIUrl":"https://doi.org/10.1002/ejoc.202401245","url":null,"abstract":"The non‐covalent interactions in molecules play important roles towards their applications in various aspects such as molecular recognition, catalysis, supramolecular chemistry, structural biology, pharmacology etc. Interestingly, among various non‐bonding interactions, chalcogen bonding (ChB) has been extensively studied in different facets of crystal engineering over the last several years. The present study demonstrates the presence of Se···N or Se···Se ChB in the benzimidazole‐fused cyclic selenazonium selenocyanates (6‐8), cyclic selenazinium selenocyanates (9‐10) and the acyclic benzimidazolium analogs having two different types of selenocyanate units (11‐12). The final organoselenium compounds were synthesized from benzimidazole in several steps in reasonably good yields. The single crystal X‐ray structures of the compounds revealed that both the N atom and Se atom of the negatively charged SeCN unit act as ChB acceptors in building the Se···N or Se···Se ChB interactions along with the additional hydrogen bonding (HB) interactions. Moreover, the structural optimization and natural bond orbital (NBO) analyses were carried out using density functional theory (DFT) to calculate the natural charges on different Se centers and the strength of second‐order perturbation energy (E2) for the ChB interactions. Finally, electrostatic potential surface (SEP) of the compounds was developed to visualize the formation of σ‐holes.","PeriodicalId":167,"journal":{"name":"European Journal of Organic Chemistry","volume":"71 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142596796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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