CCS Chemistry最新文献

{"title":"Asymmetric Amination of Primary Alcohols via Dynamic Kinetic Resolution: Enantioconvergent Access to Chiral Benzomorpholines","authors":"Yaru Gao, Guorong Hong, Lei Zhang, Ke-Yin Ye, Jiajia Cheng, Bin-Miao Yang, Yu Zhao","doi":"10.31635/ccschem.024.202404559","DOIUrl":"https://doi.org/10.31635/ccschem.024.202404559","url":null,"abstract":"<p>We present here a catalytic enantioconvergent amination of alcohols for efficient access to chiral C2- and C3-substituted benzomorpholines. The racemic amino alcohol substrates of different substitution patterns, which are readily available from a common precursor, can be converted to the enantioenriched heterocycles in a highly atom- and step-economical fashion. In particular, an unprecedented asymmetric amination of racemic primary alcohols via dynamic kinetic resolution is achieved under cooperative iridium/iron catalysis, resulting in highly enantioenriched C2-substituted benzomorpholines that are difficult to access otherwise.</p>","PeriodicalId":9810,"journal":{"name":"CCS Chemistry","volume":"9 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142313984","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}

{"title":"DNA-Compatible Photoredox Atom Transfer Radical Addition to Alkynes with Thiosulfonates","authors":"Cong Wang, Yinghui Lu, Zhiyuan Peng, Chi Zhang, Qingchao Liu, Xue-Qiang Wang, Tiezheng Jia","doi":"10.31635/ccschem.024.202404703","DOIUrl":"https://doi.org/10.31635/ccschem.024.202404703","url":null,"abstract":"<p>With the blossom of DNA encoded library (DEL) and nucleic acid aptamer techniques, DNA-compatible reactions draw increasing attention in both the pharmaceutical industry and academia. In this regard, the incorporation of organosulfur scaffolds on DNA via the Csp²–S bond exhibits advantages but remains underrepresented. Herein, we report a mild and efficient photoredox atom transfer radical addition (ATRA) to terminal and internal alkynes with thiosulfonates catalyzed by organic photocatalyst, furnishing a wide array of <i>E</i>-β-arylthiol-vinyl sulfones with excellent regio- and stereoselectivity. Mechanistic investigations demonstrate that sulfonyl radical likely served as the key intermediate in this transformation. Leveraging the broad functional group tolerance and the mild and biofriendly conditions, this protocol could be adapted to simultaneously install sulfones and sulfides on DNA. More importantly, a redox-responsive fluorescent probe (10-ethyl-2-sulfonate-acridone, ESAC) could be conveniently introduced on two commonly used aptamers (AS1411 and Sgc8c), allowing their subsequent imaging studies across a series of human tumor cell lines. Remarkably, the process of ESAC-aptamers entering the cells was captured by both confocal microscopy and flow cytometry techniques, whereby most of the ESAC-aptamers exhibited green fluorescence after their cellular uptake, with the small portion remaining in the outer membrane emitting blue fluorescence.</p>","PeriodicalId":9810,"journal":{"name":"CCS Chemistry","volume":"1 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142313982","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}

{"title":"Fluorescence Emission Modulation of Alkynyl-Functionalized Iron(II) Spin-Crossover Complexes","authors":"Yang Qu, Rong Sun, Bing-Wu Wang, Song Gao","doi":"10.31635/ccschem.024.202404670","DOIUrl":"https://doi.org/10.31635/ccschem.024.202404670","url":null,"abstract":"&lt;p&gt;Combining spin crossover (SCO) and fluorescence properties could respond to multiple physical stimulus and is meaningful for the development of switches and imaging tools. In this work, we present a new family of neutral mononuclear iron(II) complexes, denoted as Fe(&lt;b xmlns:bkstg=\"http://www.atypon.com/backstage-ns\" xmlns:fn=\"http://www.w3.org/2005/xpath-functions\" xmlns:pxje=\"java:com.atypon.frontend.services.impl.PassportXslJavaExtentions\" xmlns:urlutil=\"java:com.atypon.literatum.customization.UrlUtil\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"&gt;\u0000&lt;bold&gt;L&lt;/bold&gt;&lt;/b&gt;&lt;sup&gt;1–3&lt;/sup&gt;)&lt;sub&gt;2&lt;/sub&gt; and Fe(&lt;b xmlns:bkstg=\"http://www.atypon.com/backstage-ns\" xmlns:fn=\"http://www.w3.org/2005/xpath-functions\" xmlns:pxje=\"java:com.atypon.frontend.services.impl.PassportXslJavaExtentions\" xmlns:urlutil=\"java:com.atypon.literatum.customization.UrlUtil\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"&gt;\u0000&lt;bold&gt;L&lt;/bold&gt;&lt;/b&gt;&lt;sup&gt;3&lt;/sup&gt;)&lt;sub&gt;2&lt;/sub&gt;·CH&lt;sub&gt;2&lt;/sub&gt;Cl&lt;sub&gt;2&lt;/sub&gt; with N&lt;sub&gt;4&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; donor sets. These complexes were synthesized employing a series of tridentate Schiff base ligands, which contain an ethynyl group (H&lt;b xmlns:bkstg=\"http://www.atypon.com/backstage-ns\" xmlns:fn=\"http://www.w3.org/2005/xpath-functions\" xmlns:pxje=\"java:com.atypon.frontend.services.impl.PassportXslJavaExtentions\" xmlns:urlutil=\"java:com.atypon.literatum.customization.UrlUtil\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"&gt;\u0000&lt;bold&gt;L&lt;/bold&gt;&lt;/b&gt;&lt;sup&gt;1–3&lt;/sup&gt; = 3-ethynyl-&lt;i&gt;N&lt;/i&gt;′-((4-methylpyridin-2-yl)methylene)benzohydrazide (&lt;b xmlns:bkstg=\"http://www.atypon.com/backstage-ns\" xmlns:fn=\"http://www.w3.org/2005/xpath-functions\" xmlns:pxje=\"java:com.atypon.frontend.services.impl.PassportXslJavaExtentions\" xmlns:urlutil=\"java:com.atypon.literatum.customization.UrlUtil\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"&gt;\u0000&lt;bold&gt;4MePAH-3EyBHZ&lt;/bold&gt;&lt;/b&gt;, H&lt;b xmlns:bkstg=\"http://www.atypon.com/backstage-ns\" xmlns:fn=\"http://www.w3.org/2005/xpath-functions\" xmlns:pxje=\"java:com.atypon.frontend.services.impl.PassportXslJavaExtentions\" xmlns:urlutil=\"java:com.atypon.literatum.customization.UrlUtil\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"&gt;\u0000&lt;bold&gt;L&lt;/bold&gt;&lt;/b&gt;&lt;sup&gt;1&lt;/sup&gt;), 3-ethynyl-&lt;i&gt;N&lt;/i&gt;′-((4-methoxylpyridin-2-yl)methylene)benzohydrazide (&lt;b xmlns:bkstg=\"http://www.atypon.com/backstage-ns\" xmlns:fn=\"http://www.w3.org/2005/xpath-functions\" xmlns:pxje=\"java:com.atypon.frontend.services.impl.PassportXslJavaExtentions\" xmlns:urlutil=\"java:com.atypon.literatum.customization.UrlUtil\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"&gt;\u0000&lt;bold&gt;4OMePAH-3EyBHZ&lt;/bold&gt;&lt;/b&gt;, H&lt;b xmlns:bkstg=\"http://www.atypon.com/backstage-ns\" xmlns:fn=\"http://www.w3.org/2005/xpath-functions\" xmlns:pxje=\"java:com.atypon.frontend.services.impl.PassportXslJavaExtentions\" xmlns:urlutil=\"java:com.atypon.literatum.customization.UrlUtil\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"&gt;\u0000&lt;bold&gt;L&lt;/bold&gt;&lt;/b&gt;&lt;sup&gt;2&lt;/sup&gt;), 3-ethynyl-&lt;i&gt;N&lt;/i&gt;′-((5-methylpyridin-2-yl)methylene)benzohydrazide (&lt;b xmlns:bkstg=\"http://www.atypon.com/backstage","PeriodicalId":9810,"journal":{"name":"CCS Chemistry","volume":"120 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142313983","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}

{"title":"Generation and Application of Silyl Acyl Radicals: Facile and Metal-Free Access to Acylsilanes","authors":"","doi":"10.31635/ccschem.024.202404699","DOIUrl":"https://doi.org/10.31635/ccschem.024.202404699","url":null,"abstract":"CCS Chemistry, Ahead of Print.<br/>","PeriodicalId":9810,"journal":{"name":"CCS Chemistry","volume":"22 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142235215","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}

{"title":"Scalable Amorphous NiFe(OH)x/Fe/Graphene Bifunctional Electrocatalyst via Solution-Corrosion for Water Splitting","authors":"","doi":"10.31635/ccschem.024.202404423","DOIUrl":"https://doi.org/10.31635/ccschem.024.202404423","url":null,"abstract":"CCS Chemistry, Ahead of Print.<br/>","PeriodicalId":9810,"journal":{"name":"CCS Chemistry","volume":"27 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142235217","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}

{"title":"Double-Helical Assembly of a Copper-Silver Hydride Cluster Exhibiting Thermally Activated Delayed Fluorescence","authors":"Hu Yang, Su-Kao Peng, Wenbin Chen, Dong Luo, Shibo Xi, Shuai Lu, Yong-Liang Huang, De-Bo Hao, Bincheng Cai, Heng Wang, Mo Xie, Ming-De Li, Xiaopeng Li, Guo-Hong Ning, Dan Li","doi":"10.31635/ccschem.024.202404213","DOIUrl":"https://doi.org/10.31635/ccschem.024.202404213","url":null,"abstract":"&lt;p&gt;The synthesis of helical nanostructures with advanced functions from atomically precise building blocks is attractive, but remains a significant challenge. In this work, we report two atomically precise metal hydride clusters, Cu&lt;sub&gt;24&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt;L&lt;sub&gt;12&lt;/sub&gt;(PPh&lt;sub&gt;3&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt;Pz&lt;sub&gt;6&lt;/sub&gt; (&lt;b xmlns:bkstg=\"http://www.atypon.com/backstage-ns\" xmlns:fn=\"http://www.w3.org/2005/xpath-functions\" xmlns:pxje=\"java:com.atypon.frontend.services.impl.PassportXslJavaExtentions\" xmlns:urlutil=\"java:com.atypon.literatum.customization.UrlUtil\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"&gt;\u0000&lt;bold&gt;Cu@Cu&lt;sub&gt;23&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt;&lt;/bold&gt;&lt;/b&gt;,) and Cu&lt;sub&gt;24-x&lt;/sub&gt;Ag&lt;sub&gt;x&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt;L&lt;sub&gt;12&lt;/sub&gt;(PPh&lt;sub&gt;3&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt;Pz&lt;sub&gt;6&lt;/sub&gt; (0 &gt; x &gt; 1) (&lt;b xmlns:bkstg=\"http://www.atypon.com/backstage-ns\" xmlns:fn=\"http://www.w3.org/2005/xpath-functions\" xmlns:pxje=\"java:com.atypon.frontend.services.impl.PassportXslJavaExtentions\" xmlns:urlutil=\"java:com.atypon.literatum.customization.UrlUtil\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"&gt;\u0000&lt;bold&gt;Ag@Cu&lt;sub&gt;23&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt;&lt;/bold&gt;&lt;/b&gt;) (L= CH&lt;sub&gt;3&lt;/sub&gt;OPhC≡C&lt;sup&gt;−&lt;/sup&gt;, Pz = 3,5-(CF&lt;sub&gt;3&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt;-pyrazolate), containing M@Cu&lt;sub&gt;23&lt;/sub&gt; (M=Cu/Ag) kernels with D&lt;sub&gt;3&lt;/sub&gt;-symmetry. Single crystal X-ray diffraction results reveal that the DNA-like double-helical nanostructures driven by intrastrand and interstrand supramolecular interactions, including weak hydrogen bonds (i.e., C–H···F/O/C) and van der Waal’s interactions (i.e., C···F and F···F), are formed through the self-hierarchical assembly of&lt;b xmlns:bkstg=\"http://www.atypon.com/backstage-ns\" xmlns:fn=\"http://www.w3.org/2005/xpath-functions\" xmlns:pxje=\"java:com.atypon.frontend.services.impl.PassportXslJavaExtentions\" xmlns:urlutil=\"java:com.atypon.literatum.customization.UrlUtil\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"&gt;\u0000&lt;bold&gt; Cu@Cu&lt;sub&gt;23&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt;&lt;/bold&gt;&lt;/b&gt; and &lt;b xmlns:bkstg=\"http://www.atypon.com/backstage-ns\" xmlns:fn=\"http://www.w3.org/2005/xpath-functions\" xmlns:pxje=\"java:com.atypon.frontend.services.impl.PassportXslJavaExtentions\" xmlns:urlutil=\"java:com.atypon.literatum.customization.UrlUtil\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"&gt;\u0000&lt;bold&gt;Ag@Cu&lt;sub&gt;23&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt;&lt;/bold&gt;&lt;/b&gt;. In addition, &lt;b xmlns:bkstg=\"http://www.atypon.com/backstage-ns\" xmlns:fn=\"http://www.w3.org/2005/xpath-functions\" xmlns:pxje=\"java:com.atypon.frontend.services.impl.PassportXslJavaExtentions\" xmlns:urlutil=\"java:com.atypon.literatum.customization.UrlUtil\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"&gt;\u0000&lt;bold&gt;Cu@Cu&lt;sub&gt;23&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt;&lt;/bold&gt;&lt;/b&gt; is nonemissive. After doping with Ag, &lt;b xmlns:bkstg=\"http://www.atypon.com/backstage-ns\" xmlns:fn=\"http://www.w3.org/2005/xpath-functions\" xmlns:pxje=\"java:com.atypon.frontend.services.impl.PassportXslJavaExtentions\" xmlns:urlutil=\"java:com.atypon.literatum.customization.UrlUtil\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"&gt;\u0000&lt;bold&gt;Ag@Cu&lt;sub&gt;23&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt;&lt;","PeriodicalId":9810,"journal":{"name":"CCS Chemistry","volume":"33 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142236297","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}

{"title":"Heterogenization of a Dinuclear Cobalt Molecular Catalyst in Porous Polymers via Covalent Strategy for CO2 Photoreduction with Record CO Production Efficiency","authors":"","doi":"10.31635/ccschem.024.202404675","DOIUrl":"https://doi.org/10.31635/ccschem.024.202404675","url":null,"abstract":"CCS Chemistry, Ahead of Print.<br/>","PeriodicalId":9810,"journal":{"name":"CCS Chemistry","volume":"11 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142235216","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}

{"title":"Rhodium(I)-Catalyzed Asymmetric Alkyl Carbene B–H Bond Insertion: Enantioselective Synthesis of Versatile Chiral Alkylboranes","authors":"Jian-Guo Liu, Bo Liu, Ziyan Li, Ming-Hua Xu","doi":"10.31635/ccschem.024.202404591","DOIUrl":"https://doi.org/10.31635/ccschem.024.202404591","url":null,"abstract":"<p>Recent advances in transition metal-asymmetric carbene B–H insertion reactions provide a straightforward and powerful protocol to access chiral organoboron compounds. However, the related reaction involving linear alkyl carbenes has not been successfully developed. Apart from the difficulty of controlling the enantioselectivity, another major challenge is the high propensity of the alkyl metal carbene to undergo a β-hydride migration to form undesired alkenes. Herein, we report our development of an efficient alkyl carbene B–H insertion reaction using rhodium(I)/diene complexes as the catalysts. This simple catalytic system not only reduces the formation of alkene byproduct but also achieves high enantioselectivity of the carbene B–H insertion. This method facilitates easy asymmetric access to a wide variety of structurally diverse alkylboranes in high yields, and their further synthetic application and transformation have also been described. Mechanistic studies show that the β-hydride migration is less favorable than the carbene insertion pathway under the rhodium(I)/diene catalytic system and that the B–H bond insertion is the rate-limiting step.</p>","PeriodicalId":9810,"journal":{"name":"CCS Chemistry","volume":"83 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142166602","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}

{"title":"Asymmetric Self-Assembled Monolayer as Hole Transport Layer Enables Binary Organic Solar Cells Based on PM6: Y6 with Over 19% Efficiency","authors":"","doi":"10.31635/ccschem.024.202404707","DOIUrl":"https://doi.org/10.31635/ccschem.024.202404707","url":null,"abstract":"CCS Chemistry, Ahead of Print.<br/>","PeriodicalId":9810,"journal":{"name":"CCS Chemistry","volume":"104 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142166600","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}

{"title":"A Smart MicroRNA-Programmable Metal Catalyst for the On-Site Amplified Imaging-Guided Phototherapy","authors":"Kaiyue Tan, Qingqing Zhang, Jinhua Shang, Yuqiu He, Xiaoqing Liu, Fuan Wang","doi":"10.31635/ccschem.024.202404452","DOIUrl":"https://doi.org/10.31635/ccschem.024.202404452","url":null,"abstract":"CCS Chemistry, Ahead of Print.<br/>","PeriodicalId":9810,"journal":{"name":"CCS Chemistry","volume":"72 1","pages":""},"PeriodicalIF":11.2,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142166601","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}