Pub Date : 2024-10-21DOI: 10.1016/j.chempr.2024.09.029
Alexandros A. Kitos, Raúl Castañeda, Zachary J. Comeau, Niki Mavragani, Nicholas D. Calvert, Alexia Kirby, Francisco M. Martinez-Santiesteban, Peter J. Pallister, Timothy J. Scholl, Muralee Murugesu, Adam J. Shuhendler, Jaclyn L. Brusso
Transition metal molecular clusters hold great promise as magnetic resonance imaging (MRI) probes, where careful chemical design can afford control over the size, shape, and total spin state of the contrast agent (CA). Although such clusters can act as a single entity, exhibiting advanced in situ reactivity to key diagnostic biomolecules, their dissociation/speciation in biological media hinders their potential as MRI CAs. To resolve this, the N-2-pyrimidylimidoyl-2-pyrimidylamidine chelate was employed to selectively bind 3d metal ions, forming highly stable mixed-metal clusters. Through spectroscopic, electrochemical, and magnetic analysis, along with in vitro and in vivo studies, the application of iron and manganese homo- and heterometallic complexes as MRI CAs capable of mapping tumor redox status through a simple T1w/T2w ratiometric approach was demonstrated. The use of heteropolynuclear 3d super-atomic complexes suitable for semi-quantitative in vivo MRI of tissue redox status opens new avenues for non-invasive characterization of biochemical microenvironments by MRI.
过渡金属分子团簇很有希望成为磁共振成像（MRI）探针，精心的化学设计可以控制造影剂（CA）的大小、形状和总自旋状态。虽然此类团簇可以作为单一实体发挥作用，对关键的诊断生物分子表现出先进的原位反应性，但它们在生物介质中的解离/分化阻碍了它们作为磁共振成像造影剂的潜力。为了解决这个问题，我们采用了 N-2-嘧啶亚氨酰基-2-嘧啶脒螯合物来选择性地结合 3d 金属离子，形成高度稳定的混合金属团簇。通过光谱、电化学和磁性分析，以及体外和体内研究，证明了铁和锰同金属和异金属复合物作为磁共振成像 CAs 的应用，能够通过简单的 T1w/T2w 比率测量法绘制肿瘤氧化还原状态图。使用适用于组织氧化还原状态半定量活体磁共振成像的异多核 3d 超原子复合物，为通过磁共振成像无创描述生化微环境开辟了新途径。
{"title":"Cluster-based redox-responsive super-atomic MRI contrast agents","authors":"Alexandros A. Kitos, Raúl Castañeda, Zachary J. Comeau, Niki Mavragani, Nicholas D. Calvert, Alexia Kirby, Francisco M. Martinez-Santiesteban, Peter J. Pallister, Timothy J. Scholl, Muralee Murugesu, Adam J. Shuhendler, Jaclyn L. Brusso","doi":"10.1016/j.chempr.2024.09.029","DOIUrl":"https://doi.org/10.1016/j.chempr.2024.09.029","url":null,"abstract":"Transition metal molecular clusters hold great promise as magnetic resonance imaging (MRI) probes, where careful chemical design can afford control over the size, shape, and total spin state of the contrast agent (CA). Although such clusters can act as a single entity, exhibiting advanced <em>in situ</em> reactivity to key diagnostic biomolecules, their dissociation/speciation in biological media hinders their potential as MRI CAs. To resolve this, the <em>N</em>-2-pyrimidylimidoyl-2-pyrimidylamidine chelate was employed to selectively bind 3d metal ions, forming highly stable mixed-metal clusters. Through spectroscopic, electrochemical, and magnetic analysis, along with <em>in vitro</em> and <em>in vivo</em> studies, the application of iron and manganese homo- and heterometallic complexes as MRI CAs capable of mapping tumor redox status through a simple <em>T</em><sub>1</sub>w/<em>T</em><sub>2</sub>w ratiometric approach was demonstrated. The use of heteropolynuclear 3d super-atomic complexes suitable for semi-quantitative <em>in vivo</em> MRI of tissue redox status opens new avenues for non-invasive characterization of biochemical microenvironments by MRI.","PeriodicalId":268,"journal":{"name":"Chem","volume":"12 1","pages":""},"PeriodicalIF":23.5,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-21DOI: 10.1016/j.chempr.2024.09.027
Chenchen Du, Alex C. Padgham, Anna G. Slater, Liang Zhang
The development of flow processes for metal-ligand self-assembly and ring-closing metathesis has facilitated the efficient and scalable preparation of iron(II) pentafoil knot and Star of David [2]catenane. Use of a flow reactor also enables the formation of the otherwise inaccessible coordinatively labile zinc(II) pentameric helicate, leading to an efficient two-step synthesis of the zinc(II) pentafoil knot. As the first example of topology-synthesis in flow, our work demonstrates that the metal-ligand self-assembly can be readily adapted to flow techniques, even for labile complexes that are difficult to prepare in batches. The method is well-positioned for expansion to other topological complexes made from the metal template approach. Transitioning from laboratory batch synthesis to efficient large-scale production using continuous flow reactors not only paves the way for new applications of flow synthesis in chemical topology but also enhances the accessibility of these “hard-to-make” entangled moieties, thereby opening avenues for exploring their applications in various fields.
{"title":"Efficient flow synthesis of a Star of David [2]catenane and a pentafoil knot","authors":"Chenchen Du, Alex C. Padgham, Anna G. Slater, Liang Zhang","doi":"10.1016/j.chempr.2024.09.027","DOIUrl":"https://doi.org/10.1016/j.chempr.2024.09.027","url":null,"abstract":"The development of flow processes for metal-ligand self-assembly and ring-closing metathesis has facilitated the efficient and scalable preparation of iron(II) pentafoil knot and Star of David [2]catenane. Use of a flow reactor also enables the formation of the otherwise inaccessible coordinatively labile zinc(II) pentameric helicate, leading to an efficient two-step synthesis of the zinc(II) pentafoil knot. As the first example of topology-synthesis in flow, our work demonstrates that the metal-ligand self-assembly can be readily adapted to flow techniques, even for labile complexes that are difficult to prepare in batches. The method is well-positioned for expansion to other topological complexes made from the metal template approach. Transitioning from laboratory batch synthesis to efficient large-scale production using continuous flow reactors not only paves the way for new applications of flow synthesis in chemical topology but also enhances the accessibility of these “hard-to-make” entangled moieties, thereby opening avenues for exploring their applications in various fields.","PeriodicalId":268,"journal":{"name":"Chem","volume":"12 1","pages":""},"PeriodicalIF":23.5,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-21DOI: 10.1016/j.chempr.2024.09.030
Libo Zhu, Chang Chen, Tiantian Wu, Xu Yu, Han Tian, Fantao Kong, Ziwei Chang, Wenshu Luo, Xiangzhi Cui, Jianlin Shi
A promising fuel cell using the acidic hydrogen evolution reaction (HER) instead of kinetically sluggish oxygen reduction reaction to couple with the borohydride oxidation reaction (BOR) has been established. This BOR-HER fuel cell (BHFC) has achieved the concurrent electricity generation and hydrogen production. To catalyze HER/BOR, a copper (Cu)-doped cobalt phosphide nanosheet grown on Cu foam (Cu–CoP/CF) was developed, which exhibits significantly inhibited competitive NaBH4 hydrolysis during BOR, along with excellent HER performance and stability over 700 h. Specifically, the Cu(0), in situ formed on the surface of Cu–CoP/CF, plays a decisive role in creating an OH−-enriched local environment, resulting in significantly inhibited borohydride hydrolysis but greatly enhanced BOR selectivity of up to 85%, as well as the reduced thermodynamic barrier of BOR. The assembled BHFC equipped with Cu–CoP/CF is capable of generating a high power density of 114 mW cm−2 and concurrently producing hydrogen at a rate of at least 40 mol h−1 m−2 at cathode.
利用酸性氢进化反应（HER）代替动力学迟缓的氧还原反应，与硼氢化物氧化反应（BOR）耦合的燃料电池已经建立。这种 BOR-HER 燃料电池（BHFC）实现了同时发电和制氢。为了催化 HER/BOR，研究人员开发了一种生长在泡沫铜（Cu）上的掺铜磷化钴纳米片（Cu-CoP/CF），该纳米片在 BOR 过程中显著抑制了 NaBH4 的竞争性水解，同时还具有优异的 HER 性能和超过 700 小时的稳定性。具体来说，Cu-CoP/CF 表面原位形成的 Cu(0) 在创造富含 OH 的局部环境方面起着决定性作用，从而显著抑制了硼氢化物的水解，但大大提高了 BOR 的选择性（高达 85%），并降低了 BOR 的热力学势垒。装配有 Cu-CoP/CF 的 BHFC 能够产生 114 mW cm-2 的高功率密度，同时在阴极以至少 40 mol h-1 m-2 的速率产生氢气。
{"title":"Borohydride oxidation-water reduction fuel cells advanced by local hydroxyl enrichment-inhibited borohydride hydrolysis on Cu(0) sites","authors":"Libo Zhu, Chang Chen, Tiantian Wu, Xu Yu, Han Tian, Fantao Kong, Ziwei Chang, Wenshu Luo, Xiangzhi Cui, Jianlin Shi","doi":"10.1016/j.chempr.2024.09.030","DOIUrl":"https://doi.org/10.1016/j.chempr.2024.09.030","url":null,"abstract":"A promising fuel cell using the acidic hydrogen evolution reaction (HER) instead of kinetically sluggish oxygen reduction reaction to couple with the borohydride oxidation reaction (BOR) has been established. This BOR-HER fuel cell (BHFC) has achieved the concurrent electricity generation and hydrogen production. To catalyze HER/BOR, a copper (Cu)-doped cobalt phosphide nanosheet grown on Cu foam (Cu–CoP/CF) was developed, which exhibits significantly inhibited competitive NaBH<sub>4</sub> hydrolysis during BOR, along with excellent HER performance and stability over 700 h. Specifically, the Cu(0), <em>in situ</em> formed on the surface of Cu–CoP/CF, plays a decisive role in creating an OH<sup>−</sup>-enriched local environment, resulting in significantly inhibited borohydride hydrolysis but greatly enhanced BOR selectivity of up to 85%, as well as the reduced thermodynamic barrier of BOR. The assembled BHFC equipped with Cu–CoP/CF is capable of generating a high power density of 114 mW cm<sup>−2</sup> and concurrently producing hydrogen at a rate of at least 40 mol h<sup>−1</sup> m<sup>−2</sup> at cathode.","PeriodicalId":268,"journal":{"name":"Chem","volume":"24 1","pages":""},"PeriodicalIF":23.5,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-21DOI: 10.1016/j.chempr.2024.09.028
Alexander M. Gilchrist, Daniel A. McNaughton, Mohamed Fares, Xin Wu, Bryson A. Hawkins, Stephen J. Butler, David E. Hibbs, Philip A. Gale
Synthetic anion transporters provide a promising avenue to treat diseases such as cystic fibrosis and cancer. Anion binding site preorganization is one aspect of transporter design that can be manipulated to enhance binding. Macrocycles possess preorganized binding cavities, enabling more selective and efficient anion binding and transport. In this study, we build on a macrocyclic tetralactam scaffold by preparing a series of fluorinated and non-fluorinated tetralactam anion transporters. Anion binding and transport assays were used to analyze the substituent effects on scaffold lipophilicity, selectivity, solubility, binding strength, and transport rates. The series was analyzed for the ability to bind and transport Cl− and F− anions across lipid bilayers. Some highly fluorinated tetralactams display extremely high levels of Cl− and F− transport activity, showing record activities in 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS) assays and a Eu(III) probe-based F− transport assay.
{"title":"Tetralactam-based anion transporters","authors":"Alexander M. Gilchrist, Daniel A. McNaughton, Mohamed Fares, Xin Wu, Bryson A. Hawkins, Stephen J. Butler, David E. Hibbs, Philip A. Gale","doi":"10.1016/j.chempr.2024.09.028","DOIUrl":"https://doi.org/10.1016/j.chempr.2024.09.028","url":null,"abstract":"Synthetic anion transporters provide a promising avenue to treat diseases such as cystic fibrosis and cancer. Anion binding site preorganization is one aspect of transporter design that can be manipulated to enhance binding. Macrocycles possess preorganized binding cavities, enabling more selective and efficient anion binding and transport. In this study, we build on a macrocyclic tetralactam scaffold by preparing a series of fluorinated and non-fluorinated tetralactam anion transporters. Anion binding and transport assays were used to analyze the substituent effects on scaffold lipophilicity, selectivity, solubility, binding strength, and transport rates. The series was analyzed for the ability to bind and transport Cl<sup>−</sup> and F<sup>−</sup> anions across lipid bilayers. Some highly fluorinated tetralactams display extremely high levels of Cl<sup>−</sup> and F<sup>−</sup> transport activity, showing record activities in 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS) assays and a Eu(III) probe-based F<sup>−</sup> transport assay.","PeriodicalId":268,"journal":{"name":"Chem","volume":"20 1","pages":""},"PeriodicalIF":23.5,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-16DOI: 10.1016/j.chempr.2024.09.017
Jose M. Carceller, Bhumika Jayee, Claire G. Page, Daniel G. Oblinsky, Gustavo Mondragón-Solórzano, Nithin Chintala, Jingzhe Cao, Zayed Alassad, Zheyu Zhang, Nathaniel White, Danny J. Diaz, Andrew D. Ellington, Gregory D. Scholes, Sijia S. Dong, Todd K. Hyster
Photoenzymatic reactions involving flavin-dependent “ene”-reductases (EREDs) rely on protein-templated charge transfer (CT) complexes between the cofactor and substrate for radical initiation. These complexes typically absorb in the blue region of the electromagnetic spectrum. Here, we engineered an ERED to form CT complexes that absorb red light. Mechanistic studies indicate that red-light activity is due to the growth of a red-absorbing shoulder off the previously identified cyan absorption feature. Molecular dynamics simulations, docking, and excited-state calculations suggest that the cyan feature involves a π→π∗ transition on flavin, whereas the red-light absorption is a π→π∗ transition between flavin and the substrate. Differences in the electronic transition are due to changes in the substrate-binding conformation and allosteric tuning of the electronic structure of the cofactor-substrate complex. Microenvironment tuning of the CT complex for red-light activity is observed with other engineered photoenzymatic reactions, highlighting this effect’s generality.
{"title":"Engineering a photoenzyme to use red light","authors":"Jose M. Carceller, Bhumika Jayee, Claire G. Page, Daniel G. Oblinsky, Gustavo Mondragón-Solórzano, Nithin Chintala, Jingzhe Cao, Zayed Alassad, Zheyu Zhang, Nathaniel White, Danny J. Diaz, Andrew D. Ellington, Gregory D. Scholes, Sijia S. Dong, Todd K. Hyster","doi":"10.1016/j.chempr.2024.09.017","DOIUrl":"https://doi.org/10.1016/j.chempr.2024.09.017","url":null,"abstract":"Photoenzymatic reactions involving flavin-dependent “ene”-reductases (EREDs) rely on protein-templated charge transfer (CT) complexes between the cofactor and substrate for radical initiation. These complexes typically absorb in the blue region of the electromagnetic spectrum. Here, we engineered an ERED to form CT complexes that absorb red light. Mechanistic studies indicate that red-light activity is due to the growth of a red-absorbing shoulder off the previously identified cyan absorption feature. Molecular dynamics simulations, docking, and excited-state calculations suggest that the cyan feature involves a π→π∗ transition on flavin, whereas the red-light absorption is a π→π∗ transition between flavin and the substrate. Differences in the electronic transition are due to changes in the substrate-binding conformation and allosteric tuning of the electronic structure of the cofactor-substrate complex. Microenvironment tuning of the CT complex for red-light activity is observed with other engineered photoenzymatic reactions, highlighting this effect’s generality.","PeriodicalId":268,"journal":{"name":"Chem","volume":"11 1","pages":""},"PeriodicalIF":23.5,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142439790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-16DOI: 10.1016/j.chempr.2024.09.020
Aramballi J. Savyasachi, Oxana Kotova, Ena T. Luis, Amy D. Lynes, Shaun Mills, Sandra A. Bright, Gavin J. McManus, Matthias E. Möbius, D. Clive Williams, Robert Pal, John J. Boland, Thorfinnur Gunnlaugsson
Small structural changes to benzene-1,3,5-tricarboxamide (BTA) dictate its self-assembly behavior and morphological outcome. Functionalization with an α-amino acid close to the BTA core, which also possesses a terminal terpyridine (tpy) unit, led to a robust gel in the case of glycine, whereas monodisperse, solid microspheres formed in the case of alanine, phenylalanine, and leucine. The self-assembly pathways of the chiral and achiral BTAs are orthogonal and both microspheres and gel fibers independently assemble in the same medium. Further hierarchical self-assembly results upon addition of lanthanide ions (i.e., Eu(III) and Tb(III) that emit at long wavelengths with long excited-state lifetimes) that crosslink the microspheres through coordination, whereas coordination within the gel led to a change in morphology toward microspheres, as well as the formation of hierarchical superstructures. The chirality of the BTA influences helicity of the assembly and the resulting enantiomeric conformation around the lanthanides, evidenced by circularly polarized luminescence.
{"title":"Exerting control of self-assembly pathways via morphological switching and patterning in amino-acid-based benzene-1,3,5-tricarboxamide conjugates","authors":"Aramballi J. Savyasachi, Oxana Kotova, Ena T. Luis, Amy D. Lynes, Shaun Mills, Sandra A. Bright, Gavin J. McManus, Matthias E. Möbius, D. Clive Williams, Robert Pal, John J. Boland, Thorfinnur Gunnlaugsson","doi":"10.1016/j.chempr.2024.09.020","DOIUrl":"https://doi.org/10.1016/j.chempr.2024.09.020","url":null,"abstract":"Small structural changes to benzene-1,3,5-tricarboxamide (BTA) dictate its self-assembly behavior and morphological outcome. Functionalization with an α-amino acid close to the BTA core, which also possesses a terminal terpyridine (tpy) unit, led to a robust gel in the case of glycine, whereas monodisperse, solid microspheres formed in the case of alanine, phenylalanine, and leucine. The self-assembly pathways of the chiral and achiral BTAs are orthogonal and both microspheres and gel fibers independently assemble in the same medium. Further hierarchical self-assembly results upon addition of lanthanide ions (i.e., Eu(III) and Tb(III) that emit at long wavelengths with long excited-state lifetimes) that crosslink the microspheres through coordination, whereas coordination within the gel led to a change in morphology toward microspheres, as well as the formation of hierarchical superstructures. The chirality of the BTA influences helicity of the assembly and the resulting enantiomeric conformation around the lanthanides, evidenced by circularly polarized luminescence.","PeriodicalId":268,"journal":{"name":"Chem","volume":"11 1","pages":""},"PeriodicalIF":23.5,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142439928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-16DOI: 10.1016/j.chempr.2024.09.016
Eugene Yew Kun Tan, Alireza Dehdari, Amirah S. Mat Lani, Derek A. Pratt, Shunsuke Chiba
Dearomatization of two-dimensional planar aromatic feedstocks is an attractive strategy for the introduction of three-dimensional vectors into chemical scaffolds to expand chemical space for drug discovery. Here, we demonstrate the dearomative dimerization and skeletal rearrangement of quinolines under polysulfide anion photocatalysis, in which the additive dictates the reaction courses. In the presence of formate, dearomative dimerization of quinolines is followed by cyclization to form an sp3-rich polyheterocyclic hybrid of a 2,5-methanobenzo[b]azepine and a tetrahydroquinoline in a net-reductive manner. On the other hand, in the presence of triethylamine instead of formate, sequential dimerization and skeletal rearrangement occurs to afford 4-(3-indolylmethyl)quinolines in a redox-neutral manner. These observations enabled the design of a net-reductive skeletal rearrangement of 4-arylquinolines to 3-(arylmethyl)indoles. Detailed mechanistic investigations revealed that this umpolung transformation from electron-deficient quinolines to electron-rich indoles is mediated via a 1,2-aryl migration/ring-contraction sequence, as opposed to the more commonly invoked neophyl-like rearrangement.
{"title":"Dearomative dimerization of quinolines and their skeletal rearrangement to indoles triggered by single-electron transfer","authors":"Eugene Yew Kun Tan, Alireza Dehdari, Amirah S. Mat Lani, Derek A. Pratt, Shunsuke Chiba","doi":"10.1016/j.chempr.2024.09.016","DOIUrl":"https://doi.org/10.1016/j.chempr.2024.09.016","url":null,"abstract":"Dearomatization of two-dimensional planar aromatic feedstocks is an attractive strategy for the introduction of three-dimensional vectors into chemical scaffolds to expand chemical space for drug discovery. Here, we demonstrate the dearomative dimerization and skeletal rearrangement of quinolines under polysulfide anion photocatalysis, in which the additive dictates the reaction courses. In the presence of formate, dearomative dimerization of quinolines is followed by cyclization to form an sp<sup>3</sup>-rich polyheterocyclic hybrid of a 2,5-methanobenzo[<em>b</em>]azepine and a tetrahydroquinoline in a net-reductive manner. On the other hand, in the presence of triethylamine instead of formate, sequential dimerization and skeletal rearrangement occurs to afford 4-(3-indolylmethyl)quinolines in a redox-neutral manner. These observations enabled the design of a net-reductive skeletal rearrangement of 4-arylquinolines to 3-(arylmethyl)indoles. Detailed mechanistic investigations revealed that this umpolung transformation from electron-deficient quinolines to electron-rich indoles is mediated via a 1,2-aryl migration/ring-contraction sequence, as opposed to the more commonly invoked neophyl-like rearrangement.","PeriodicalId":268,"journal":{"name":"Chem","volume":"18 1","pages":""},"PeriodicalIF":23.5,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142439965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-16DOI: 10.1016/j.chempr.2024.09.002
Manjur O. Akram, Caleb D. Martin
In this issue of Chem, Kinjo and Feng report the synthesis of a cyclotriborate trianion (B3R63−), a highly charged boron ring system with discrete two-center two-electron bonds. With three contiguous borates, the B33− core of the feature compound defies Coulomb’s law and represents the first homocyclic boron analog of the ubiquitous cyclopropane. The remarkable stability enabled full characterization and opens new vistas in the field of multiply charged boron ions.
{"title":"The cyclotriborate trianion","authors":"Manjur O. Akram, Caleb D. Martin","doi":"10.1016/j.chempr.2024.09.002","DOIUrl":"https://doi.org/10.1016/j.chempr.2024.09.002","url":null,"abstract":"In this issue of <em>Chem</em>, Kinjo and Feng report the synthesis of a cyclotriborate trianion (B<sub>3</sub>R<sub>6</sub><sup>3−</sup>), a highly charged boron ring system with discrete two-center two-electron bonds. With three contiguous borates, the B<sub>3</sub><sup>3−</sup> core of the feature compound defies Coulomb’s law and represents the first homocyclic boron analog of the ubiquitous cyclopropane. The remarkable stability enabled full characterization and opens new vistas in the field of multiply charged boron ions.","PeriodicalId":268,"journal":{"name":"Chem","volume":"94 1","pages":""},"PeriodicalIF":23.5,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142439926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-15DOI: 10.1016/j.chempr.2024.09.015
Federico Villalobos, Jan Berger, Adam Matěj, Reed Nieman, Ana Sánchez-Grande, Diego Soler, Andrés Pinar Solé, Hans Lischka, Mikuláš Matoušek, Jiri Brabec, Libor Veis, Alba Millan, Carlos Sánchez-Sánchez, Araceli G. Campaña, Juan M. Cuerva, Pavel Jelínek
Molecular π-magnets based on single organic molecules have attracted increasing attention for their potential applications in optoelectronics and spintronics. Global aromaticity in conjugated macrocyclic polyradicaloids is still an open question that has only been tackled in molecules with an even number of electrons. Here, we report the on-surface synthesis of a cyclopenta-ring-fused oligo(m-phenylene) macrocycle, 9MC, with an odd number of electrons. The generated polyradicaloid undergoes a surface-induced distortion to a D3h symmetry with a fully delocalized doublet ground state. Interestingly, 9MC exhibits two aromatic annulene-within-an-annulene (AWA) ring currents in the inner and outer rings.
{"title":"Globally aromatic odd-electron π-magnetic macrocycle","authors":"Federico Villalobos, Jan Berger, Adam Matěj, Reed Nieman, Ana Sánchez-Grande, Diego Soler, Andrés Pinar Solé, Hans Lischka, Mikuláš Matoušek, Jiri Brabec, Libor Veis, Alba Millan, Carlos Sánchez-Sánchez, Araceli G. Campaña, Juan M. Cuerva, Pavel Jelínek","doi":"10.1016/j.chempr.2024.09.015","DOIUrl":"https://doi.org/10.1016/j.chempr.2024.09.015","url":null,"abstract":"Molecular π-magnets based on single organic molecules have attracted increasing attention for their potential applications in optoelectronics and spintronics. Global aromaticity in conjugated macrocyclic polyradicaloids is still an open question that has only been tackled in molecules with an even number of electrons. Here, we report the on-surface synthesis of a cyclopenta-ring-fused oligo(<em>m</em>-phenylene) macrocycle, <strong>9MC</strong>, with an odd number of electrons. The generated polyradicaloid undergoes a surface-induced distortion to a <em>D</em><sub><em>3</em>h</sub> symmetry with a fully delocalized doublet ground state. Interestingly, <strong>9MC</strong> exhibits two aromatic annulene-within-an-annulene (AWA) ring currents in the inner and outer rings.","PeriodicalId":268,"journal":{"name":"Chem","volume":"56 1","pages":""},"PeriodicalIF":23.5,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142436152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-10DOI: 10.1016/j.chempr.2024.09.013
Zhuo Huang , Xinxing Zhang
Organic cages, featuring the selective stimuli response and reversible encapsulation of guest molecules, demonstrate a huge potential in guest-triggered actuation. In this issue of Chem, Khashab and co-workers exploited host-guest recognition of organic urea cages with three-dimensional structures to integrate multiple mechanical actuations into a single material for the first time.
{"title":"Stimuli-responsive actuation enabled by selective host-guest recognition of urea cage","authors":"Zhuo Huang , Xinxing Zhang","doi":"10.1016/j.chempr.2024.09.013","DOIUrl":"10.1016/j.chempr.2024.09.013","url":null,"abstract":"<div><div>Organic cages, featuring the selective stimuli response and reversible encapsulation of guest molecules, demonstrate a huge potential in guest-triggered actuation. In this issue of <em>Chem</em>, Khashab and co-workers exploited host-guest recognition of organic urea cages with three-dimensional structures to integrate multiple mechanical actuations into a single material for the first time.</div></div>","PeriodicalId":268,"journal":{"name":"Chem","volume":"10 10","pages":"Pages 2943-2945"},"PeriodicalIF":19.1,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142398308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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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