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Tong WY, Su X, Sun P, Xu S, Qu S, Wang X. Understanding the Reaction Mechanism of Ni-Catalyzed Regio- and Enantioselective Hydroalkylation of Enamines: Chemoselectivity of (Bi-oxazoline)NiH. J Org Chem 2023; 88:15404-15413. [PMID: 37853516 DOI: 10.1021/acs.joc.3c01939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
This density functional theory study explores the detailed mechanism of nickel-catalyzed hydroalkylation of the C═C bond of N-Cbz-protected enamines (Cbz = benzyloxycarbonyl) with alkyl iodides to give chiral α-alkyl amines. The active catalyst (biOx)NiH, a chiral bioxazoline (biOx)-chelated Ni(I) hydride, exhibits chemoselectivity that favors single electron transfer to the alkyl iodide over C═C hydrometalation with the enamine. This generates an alkyl radical and a Ni(II) intermediate, which takes up the enamine substrate CbzNHCH═CH2CH3 via a regio- and enantioselective C═C insertion into the NiII-H bond. The resulting Ni(II) alkyl complex combines with the alkyl radical, forming a Ni(III) intermediate, from which the alkyl-alkyl reductive elimination delivers the chiral amine product. The regioselectivity arises from a combination of orbital and noncovalent interactions, both of which are induced by the Cbz group. Thus, Cbz plays an additional role in controlling regioselectivity. The enantioselectivity stems from the differing distortion energies of CbzNHCH═CH2CH3. The reductive elimination is the rate-determining step (ΔG⧧ = 18.7 kcal/mol). In addition, the calculations show a noninnocent behavior of the biOx ligand induced by the insertion of CbzNHCH═CH2CH3 into the Ni-H bond of (biOx)NiH. These computationally gained insights can have implications for developing new Ni(I)-catalyzed reactions.
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Affiliation(s)
- Wen-Yan Tong
- College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, P. R. China
- Department of Chemistry, Xi'an Jiaotong-Liverpool University, Suzhou 215123, China
| | - Xiaoxi Su
- College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, P. R. China
| | - Pengrui Sun
- Department of Chemistry, Xi'an Jiaotong-Liverpool University, Suzhou 215123, China
| | - Shaojie Xu
- Department of Chemistry, Xi'an Jiaotong-Liverpool University, Suzhou 215123, China
| | - Shuanglin Qu
- College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, P. R. China
| | - Xiaotai Wang
- Department of Chemistry, Xi'an Jiaotong-Liverpool University, Suzhou 215123, China
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2
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Li S, Tong WY, Zhou Q, Yu X, Shi JL, Li SS, Qu S, Wang J. Palladium-Catalyzed Oxidative Coupling of Dibenzosiloles with α-Diazo Esters: Formal Replacement of the Silyl Group with Carbenes. Organometallics 2023. [DOI: 10.1021/acs.organomet.3c00015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
Affiliation(s)
- Shichao Li
- Beijing National Laboratory of Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
| | - Wen-Yan Tong
- College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, Hunan, China
| | - Qi Zhou
- Beijing National Laboratory of Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
| | - Xiang Yu
- Beijing National Laboratory of Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
| | - Jiang-Ling Shi
- Beijing National Laboratory of Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
| | - Shu-Sen Li
- Beijing National Laboratory of Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
| | - Shuanglin Qu
- College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, Hunan, China
| | - Jianbo Wang
- Beijing National Laboratory of Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
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3
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Jin H, Tong WY, Zhang J, Rudolph M, Rominger F, Shen X, Qu S, Hashmi ASK. Dichotomy of platinum(II) and gold(III) carbene intermediates switching from N- to O-selectivity. Nat Commun 2022; 13:1672. [PMID: 35354823 PMCID: PMC8967914 DOI: 10.1038/s41467-022-29326-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 02/21/2022] [Indexed: 01/20/2023] Open
Abstract
Pt(II) and Au(III)-mediated intermolecular divergent annulations of benzofurazans and ynamides highlighted the N- to O-selectivity of tunable metal carbene intermediates. PtCl2 with a bulky phosphite ligand resulted in the specific synthesis of six-membered quinoxaline N-oxides and successfully suppressed the in-situ deoxygenation of N-oxides. On the other hand, an unique gold(III) catalyst (2,6-di-MeO-PyrAuCl3) led to the five-membered ring products, benzimidazoles. A broad scope of functional groups was well compatible, delivering better yields and selectivities in contrast to conventional gold(I) catalysts. The different behavior of presumed platinum(II) and gold(III) carbenes with respect to chemoselectivity was intensively examined by experiments and DFT calculations. A detailed mechanistic study, based on DFT calculations, revealed that the highly electrophilic carbocation-like gold(III) carbene triggers an oxophilic cyclization, followed by a cascade ring contraction and acyl migration. On the contrary, the Pt carbene species is less cationic, favoring the formation of the six-membered ring via N-attack. Benzofurazan, a cyclic heterocycle, can form open-chain metal carbene species in the presence of suitable catalysts. Here the authors show divergent reactivity when using gold(III) and platinum(II) catalysts, and perform computational and experimental mechanistic studies to explain the differing reactivity
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Affiliation(s)
- Hongming Jin
- School of Pharmacy, Experiment Center for Science and Technology, Nanjing University of Chinese Medicine, Nanjing, China. .,Organisch-Chemisches Institut, Im Neuenheimer Feld 270, Universität Heidelberg, Heidelberg, Germany.
| | - Wen-Yan Tong
- College of Chemistry and Chemical Engineering, Hunan University, Changsha, China
| | - Jing Zhang
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, State Key Laboratory Cultivation Base for TCM Quality and Efficacy, Nanjing University of Chinese Medicine, Nanjing, China
| | - Matthias Rudolph
- Organisch-Chemisches Institut, Im Neuenheimer Feld 270, Universität Heidelberg, Heidelberg, Germany
| | - Frank Rominger
- Organisch-Chemisches Institut, Im Neuenheimer Feld 270, Universität Heidelberg, Heidelberg, Germany
| | - Xu Shen
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, State Key Laboratory Cultivation Base for TCM Quality and Efficacy, Nanjing University of Chinese Medicine, Nanjing, China
| | - Shuanglin Qu
- College of Chemistry and Chemical Engineering, Hunan University, Changsha, China.
| | - A Stephen K Hashmi
- Organisch-Chemisches Institut, Im Neuenheimer Feld 270, Universität Heidelberg, Heidelberg, Germany.
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4
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Wang X, Tong WY, Huang B, Cao S, Li Y, Jiao J, Huang H, Yi Q, Qu S, Wang X. Convergent Synthesis of 1,4-Dicarbonyl Z-Alkenes through Three-Component Coupling of Alkynes, α-Diazo Sulfonium Triflate, and Water. J Am Chem Soc 2022; 144:4952-4965. [PMID: 35274949 DOI: 10.1021/jacs.1c12874] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We report a general protocol for the convergent synthesis of 1,4-dicarbonyl Z-alkenes form alkynes using α-diazo sulfonium triflate and water. The C═O, C═C, and C-H bonds are formed under mild conditions with a wide range of functional groups tolerated. The reaction exhibits excellent Z-selectivity and complete regioselectivity. The resulting 1,4-dicarbonyl Z-alkenes can smoothly undergo follow-up conversion to a variety of heteroaromatic scaffolds. Moreover, the reaction also provides a facile access to the corresponding deuterated Z-alkenes and deuterated heteroarenes with a high level of deuterium incorporation (90-97% D-inc.) by directly using D2O, thus rendering the method highly valuable. The comprehensive mechanistic studies indicate that a free carbyne radical intermediate is formed via the photocatalytic single electron transfer process, and KH2PO4 plays a crucial role in significant improvements on yield and selectivity based on density-functional theory calculations, providing a new direction for radical coupling reactions of diazo compounds.
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Affiliation(s)
- Xuyong Wang
- College of Chemistry and Chemical Engineering, State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha 410082, P. R. China
| | - Wen-Yan Tong
- College of Chemistry and Chemical Engineering, State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha 410082, P. R. China
| | - Bing Huang
- College of Chemistry and Chemical Engineering, State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha 410082, P. R. China
| | - Si Cao
- College of Chemistry and Chemical Engineering, State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha 410082, P. R. China
| | - Yunlong Li
- College of Chemistry and Chemical Engineering, State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha 410082, P. R. China
| | - Jingchao Jiao
- College of Chemistry and Chemical Engineering, State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha 410082, P. R. China
| | - Hang Huang
- College of Chemistry and Chemical Engineering, State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha 410082, P. R. China
| | - Qiu Yi
- College of Chemistry and Chemical Engineering, State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha 410082, P. R. China
| | - Shuanglin Qu
- College of Chemistry and Chemical Engineering, State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha 410082, P. R. China
| | - Xi Wang
- College of Chemistry and Chemical Engineering, State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha 410082, P. R. China
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Yao XQ, Tong WY, Wang K, Qu S, Wang J. Azacycle-Directed Formal Aromatic C(sp 2)–H Insertion with Cr(0) Fischer Carbene Complex via Oxidative Hydrogen Migration. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00352] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Xing-Qi Yao
- Beijing National Laboratory of Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
| | - Wen-Yan Tong
- College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 Hunan, China
| | - Kang Wang
- Beijing National Laboratory of Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
| | - Shuanglin Qu
- College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 Hunan, China
| | - Jianbo Wang
- Beijing National Laboratory of Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
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Cheng HG, Yang Z, Chen R, Cao L, Tong WY, Wei Q, Wang Q, Wu C, Qu S, Zhou Q. A Concise Total Synthesis of (-)-Berkelic Acid. Angew Chem Int Ed Engl 2021; 60:5141-5146. [PMID: 33252181 DOI: 10.1002/anie.202014660] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 11/27/2020] [Indexed: 12/19/2022]
Abstract
Reported here is a concise total synthesis of (-)-berkelic acid in eight linear steps. This synthesis features a Catellani reaction/oxa-Michael cascade for the construction of the isochroman scaffold, a one-pot deprotection/spiroacetalization operation for the formation of the tetracyclic core structure, and a late-stage Ni-catalyzed reductive coupling for the introduction of the lateral chain. Notably, four stereocenters are established from a single existing chiral center with excellent stereocontrol during the deprotection/spiroacetalization process. Stereocontrol of the intriguing deprotection/spiroacetalization process is supported by DFT calculations.
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Affiliation(s)
- Hong-Gang Cheng
- Sauvage Center for Molecular Sciences, Engineering Research Center of Organosilicon Compounds & Materials (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Zhenjie Yang
- Sauvage Center for Molecular Sciences, Engineering Research Center of Organosilicon Compounds & Materials (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Ruiming Chen
- Sauvage Center for Molecular Sciences, Engineering Research Center of Organosilicon Compounds & Materials (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Liming Cao
- Sauvage Center for Molecular Sciences, Engineering Research Center of Organosilicon Compounds & Materials (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Wen-Yan Tong
- College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China
| | - Qiang Wei
- Sauvage Center for Molecular Sciences, Engineering Research Center of Organosilicon Compounds & Materials (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Qingqing Wang
- Sauvage Center for Molecular Sciences, Engineering Research Center of Organosilicon Compounds & Materials (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Chenggui Wu
- Sauvage Center for Molecular Sciences, Engineering Research Center of Organosilicon Compounds & Materials (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Shuanglin Qu
- College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China
| | - Qianghui Zhou
- Sauvage Center for Molecular Sciences, Engineering Research Center of Organosilicon Compounds & Materials (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China.,The Institute for Advanced Studies, Wuhan University, Wuhan, 430072, China
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7
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Bian JH, Tong WY, Pitsch CE, Wu YB, Wang X. Mechanism of nickel-catalyzed direct carbonyl-Heck coupling reaction: the crucial role of second-sphere interactions. Dalton Trans 2021; 50:2654-2662. [PMID: 33527940 DOI: 10.1039/d0dt04121a] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We present a detailed DFT mechanistic study on the first Ni-catalyzed direct carbonyl-Heck coupling of aryl triflates and aldehydes to afford ketones. The precatalyst Ni(COD)2 is activated with the phosphine (phos) ligand, followed by coordination of the substrate PhOTf, to form [Ni(phos)(PhOTf)] for intramolecular PhOTf to Ni(0) oxidative addition. The ensuing phenyl-Ni(ii) triflate complex substitutes benzaldehyde for triflate by an interchange mechanism, leaving the triflate anion in the second coordination sphere held by Coulomb attraction. The Ni(ii) complex cation undergoes benzaldehyde C[double bond, length as m-dash]O insertion into the Ni-Ph bond, followed by β-hydride elimination, to produce Ni(ii)-bound benzophenone, which is released by interchange with triflate. The resulting neutral Ni(ii) hydride complex leads to regeneration of the active catalyst following base-mediated deprotonation/reduction. The benzaldehyde C[double bond, length as m-dash]O insertion is the rate-determining step. The triflate anion, while remaining in the second sphere, engages in electrostatic interactions with the first sphere, thereby stabilizing the intermediate/transition state and enabling the desired reactivity. This is the first time that such second-sphere interaction and its impact on cross-coupling reactivity has been elucidated. The new insights gained from this study can help better understand and improve Heck-type reactions.
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Affiliation(s)
- Jian-Hong Bian
- Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province and Institute of Molecular Science, Shanxi University, Taiyuan 030006, P. R. China.
| | - Wen-Yan Tong
- Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province and Institute of Molecular Science, Shanxi University, Taiyuan 030006, P. R. China.
| | - Chloe E Pitsch
- Department of Chemistry, University of Colorado Denver, Campus Box 194, P. O. Box 173364, Denver, Colorado 80217-3364, USA.
| | - Yan-Bo Wu
- Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province and Institute of Molecular Science, Shanxi University, Taiyuan 030006, P. R. China.
| | - Xiaotai Wang
- Hoffmann Institute of Advanced Materials, Shenzhen Polytechnic, 7098 Liuxian Boulevard, Nanshan District, Shenzhen 518055, P. R. China and Department of Chemistry, University of Colorado Denver, Campus Box 194, P. O. Box 173364, Denver, Colorado 80217-3364, USA.
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8
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Tong WY, Ly TD, Zhao TT, Wu YB, Wang X. Mechanism of C–P bond formation via Pd-catalyzed decarbonylative phosphorylation of amides: insight into the chemistry of the second coordination sphere. Chem Commun (Camb) 2020; 56:113-116. [DOI: 10.1039/c9cc07923h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
DFT computations establish a detailed reaction mechanism for the first Pd-catalyzed decarbonylative phosphorylation of amides forming C–P bonds, which includes non-covalent interactions as well as proton transfer in the second coordination sphere.
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Affiliation(s)
- Wen-Yan Tong
- The Key Laboratory of Energy Conversion and Storage of Shanxi Province
- Institute of Molecular Science
- Shanxi University
- Taiyuan
- People's Republic of China
| | - Thu D. Ly
- Department of Chemistry
- University of Colorado Denver
- Denver
- USA
| | - Tao-Tao Zhao
- The Key Laboratory of Energy Conversion and Storage of Shanxi Province
- Institute of Molecular Science
- Shanxi University
- Taiyuan
- People's Republic of China
| | - Yan-Bo Wu
- The Key Laboratory of Energy Conversion and Storage of Shanxi Province
- Institute of Molecular Science
- Shanxi University
- Taiyuan
- People's Republic of China
| | - Xiaotai Wang
- Department of Chemistry
- University of Colorado Denver
- Denver
- USA
- Hoffmann Institute of Advanced Materials
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9
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Zhao TT, Zhao XF, Bian JH, Tong WY, Jin B, Wang X, Yuan C, Wu YB. Computational design of species with ultrashort Be–Be distances using planar hexacoordinate carbon structures as the templates. Dalton Trans 2019; 48:6581-6587. [DOI: 10.1039/c9dt00630c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Replacing the planar hexacoordinate carbon in CX3M3+ species with the Be2 moiety leads to isoelectronic species with ultrashort Be–Be distances.
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Affiliation(s)
- Tao-Tao Zhao
- Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province
- Institute of Molecular Science
- Shanxi University
- Taiyuan
- China
| | - Xue-Feng Zhao
- Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province
- Institute of Molecular Science
- Shanxi University
- Taiyuan
- China
| | - Jian-Hong Bian
- Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province
- Institute of Molecular Science
- Shanxi University
- Taiyuan
- China
| | - Wen-Yan Tong
- Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province
- Institute of Molecular Science
- Shanxi University
- Taiyuan
- China
| | - Bo Jin
- Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province
- Institute of Molecular Science
- Shanxi University
- Taiyuan
- China
| | - Xiaotai Wang
- Department of Chemistry
- University of Colorado Denver
- Denver
- USA
| | - Caixia Yuan
- Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province
- Institute of Molecular Science
- Shanxi University
- Taiyuan
- China
| | - Yan-Bo Wu
- Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province
- Institute of Molecular Science
- Shanxi University
- Taiyuan
- China
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10
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Abstract
DFT calculations revealed that neutral polygons (E-Be2H3)n are the viable targets for realizing ultrashort metal–metal distances between main group metals.
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Affiliation(s)
- Wen-Yan Tong
- The Key Laboratory of Energy Conversion and Storage of Shanxi Province
- Institute of Molecular Science
- Shanxi University
- Taiyuan 030006
- People's Republic of China
| | - Tao-Tao Zhao
- The Key Laboratory of Energy Conversion and Storage of Shanxi Province
- Institute of Molecular Science
- Shanxi University
- Taiyuan 030006
- People's Republic of China
| | - Xue-Feng Zhao
- The Key Laboratory of Energy Conversion and Storage of Shanxi Province
- Institute of Molecular Science
- Shanxi University
- Taiyuan 030006
- People's Republic of China
| | - Xiaotai Wang
- The Key Laboratory of Energy Conversion and Storage of Shanxi Province
- Institute of Molecular Science
- Shanxi University
- Taiyuan 030006
- People's Republic of China
| | - Yan-Bo Wu
- The Key Laboratory of Energy Conversion and Storage of Shanxi Province
- Institute of Molecular Science
- Shanxi University
- Taiyuan 030006
- People's Republic of China
| | - Caixia Yuan
- The Key Laboratory of Energy Conversion and Storage of Shanxi Province
- Institute of Molecular Science
- Shanxi University
- Taiyuan 030006
- People's Republic of China
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11
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Darah I, Tong WY, Nor-Afifah S, Nurul-Aili Z, Lim SH. Antimicrobial effects of Caulerpa sertularioides extract on foodborne diarrhea-caused bacteria. Eur Rev Med Pharmacol Sci 2014; 18:171-178. [PMID: 24488904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
AIM Caulerpa (C.) sertularioides has many therapeutic uses in the practice of traditional medicine in Malaysia. Crude methanolic, diethyl ether extract, ethyl acetate extract and butanolic extract from C. sertularioides were subjected to antimicrobial screening including the three Gram-positive and three Gram-negative diarrhea-caused bacteria. MATERIALS AND METHODS The antimicrobial activities were studied by using disc diffusion method and broth dilution method. The effect of the extract on the growth profile of the bacteria was examined via time-kill assay. In addition to the bactericidal effects study, microscopic observations using Scanning electron microscopy (SEM) was done to determine the major alterations in the microstructure of Bacillus (B.) subtilis. RESULTS Ethyl acetate extract demonstrated antibacterial activity towards all the tested bacteria and produced inhibition zone ranging from ≤ 9 mm - ≥ 15 mm. However, all the tested bacteria were resistant to the butanolic extract treatment. B. subtilis growth curve in the presence of the crude methanol extract at MIC showed bacteriostatic. The main abnormalities found from these microscopic observations were morphology alteration of the bacteria cells after exposure to the methanol extract. CONCLUSIONS Data from this study revealed that C. sertularioides may be potential antimicrobial agents against foodborne Gram-positive and Gram-negative bacteria particularly cause diarrhea, and also food spoilage microorganisms.
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Affiliation(s)
- I Darah
- Industrial Biotechnology Research Laboratory (IBRL), School of Biological Sciences University Sains Malaysia, Penang, Malaysia.
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12
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Wei DZ, Yang JY, Liu JW, Tong WY. Inhibition of Liver Cancer Cell Proliferation and Migration by a Combination of (-)-Epigallocatechin-3- Gallate and Ascorbic Acid. J Chemother 2013; 15:591-5. [PMID: 14998086 DOI: 10.1179/joc.2003.15.6.591] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
A mixture of (-)-epigallocatechin-3-gallate (EGCG) and ascorbic acid exhibited 73.2% inhibition of SMMC-7721 cell proliferation in a soft agar colony formation assay, which was much higher than EGCG (40.4%) or ascorbic acid (12.4%) alone. In the cell migration assay, the mixture also significantly suppressed the migration of SMMC-7721 cells by 65.9% while EGCG and/or ascorbic acid did by 28.9% and 18.7%, respectively. Ascorbic acid was able to enhance the antioxidant activity of EGCG by decreasing the intracellular oxidative stress according to fluorographic analysis of oxidative stress. In conclusion, the combination of EGCG and ascorbic acid can strongly suppress the proliferation and metastasis of liver cancer cells, possibly with a mechanism associated with the scavenging of reactive oxygen species. All these events add to our knowledge of liver cancer chemotherapy.
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Affiliation(s)
- D Z Wei
- State Key Laboratory of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, Shanghai 200237, PR China.
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13
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Tong WY, Liang YM, Tam V, Yip HK, Kao YT, Cheung KMC, Yeung KWK, Lam YW. Biochemical characterization of the cell-biomaterial interface by quantitative proteomics. Mol Cell Proteomics 2010; 9:2089-98. [PMID: 20562470 DOI: 10.1074/mcp.m110.001966] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Surface topography and texture of cell culture substrata can affect the differentiation and growth of adherent cells. The biochemical basis of the transduction of the physical and mechanical signals to cellular responses is not well understood. The lack of a systematic characterization of cell-biomaterial interaction is the major bottleneck. This study demonstrated the use of a novel subcellular fractionation method combined with quantitative MS-based proteomics to enable the robust and high-throughput analysis of proteins at the adherence interface of Madin-Darby canine kidney cells. This method revealed the enrichment of extracellular matrix proteins and membrane and stress fibers proteins at the adherence surface, whereas it shows depletion of extracellular matrix belonging to the cytoplasmic, nucleus, and lateral and apical membranes. The asymmetric distribution of proteins between apical and adherence sides was also profiled. Apart from classical proteins with clear involvement in cell-material interactions, proteins previously not known to be involved in cell attachment were also discovered.
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Affiliation(s)
- W Y Tong
- Department of Orthopaedics and Traumatology, LKS Faculty of Medicine, Queen Mary Hospital, The University of Hong Kong, Pokfulam, Hong Kong
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14
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Guo QR, Tong WY, Wei DZ, Tao XY. Expression and purification of soluble B lymphocyte stimulator from recombinant Escherichia coli. Prikl Biokhim Mikrobiol 2008; 44:187-192. [PMID: 18669261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In this work, the expression conditions of fusion protein thioredoxin (Trx)-soluble B lymphocyte stimulator (sBLyS) in shake flask and bioreactor from the recombinant Escherichia coli BL21 (DE3) with a pET system encoding the fusion protein gene of Trx-sBLyS and the purification method of the sBLyS were optimized to effectively obtain the bioactive protein sBLyS with a high purity. A yield of about 250 mg Trx-sBLyS/g DWC (1686 mg Trx-sBLyS/L) and expression level of about 38.5% in soluble Trx-sBLyS were obtained in a 30 1 bioreactor after optimization of the fermentation conditions. After the completion of the optimized purification procedure in order of affinity chromatography, enzymatic cleavage with enterokinase and DEAE ion exchange chromatography, about 200 mg sBLyS per liter fermentation broth was obtained with a purity of about 95% and a yield of near 30%, respectively. Furthermore, the molecular weight (MW) and the isoelectric point (pI) of the purified sBLyS were determined by 2-D gel electrophoresis and SDS-PAGE analysis and estimated to be over 16 kDa and about pH 4.15, respectively. In addition, the bioactivities of the soluble Trx-sBLyS in fermentation broth and the purified sBLyS were tested by two kinds of analytical methods of bioactivity. The good fermentation yield and the satisfied, purified sBLyS product with high purity, yield and bioactivity demonstrated the sBLyS production procedure was promising in industry.
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Affiliation(s)
- Q R Guo
- Institute of New World Biotechnology, East China University of Science and Technology, Shanghai 200237, China
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15
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Tong WY, Djurisić AB, Xie MH, Ng ACM, Cheung KY, Chan WK, Leung YH, Lin HW, Gwo S. Metal Phthalocyanine Nanoribbons and Nanowires. J Phys Chem B 2006; 110:17406-13. [PMID: 16942077 DOI: 10.1021/jp062951q] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nanoribbons and nanowires of different metal phthalocyanines (copper, nickel, iron, cobalt, and zinc), as well as copper hexadecafluorophthalocyanine (F(16)CuPc), have been grown by organic vapor-phase deposition. Their properties, as a function of substrate type, source-to-substrate distance, and substrate temperature, were studied by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and absorption measurements. The size and morphology of the nanostructures were found to be mainly determined by the substrate temperature. The crystal structure was dependent on the substrate temperature as well. At substrate temperatures below 200 degrees C, in addition to straight nanoribbons, twisted nanoribbons were found for all investigated materials except F(16)CuPc, which formed helical nanoribbons upon exposure to an electron beam. The formation of different nanostructures (nanoribbons, twisted nanoribbons, and helical nanoribbons) is discussed.
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Affiliation(s)
- W Y Tong
- Department of Physics, University of Hong Kong, Pokfulam Road, Hong Kong
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16
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Abstract
An improved procedure for the fermentation and purification of human epidermal growth factor (hEGF) was developed. Recombinant Escherichia coli HB-101 [lacUV5omp08hEGF] harboring plasmid lacUV5omp08hEGF encoding hEGF was used in fermentation to increase levels of hEGF. Medium composition, and the levels of inoculum, inducer (isopropyl-beta-D-thiogalactoside) and ampicillin were optimized with respect to volumetric fermentation of hEGF. As a result, the hEGF concentration reached a high value of 242 mg l(-1) and the amount of heterogeneous protein decreased by 62% compared with that before optimization in batch fermentation. High-quality hEGF was purified from the fermentation culture by centrifugation, salting-out, resuspension, recentrifugation and finally gel chromatography on a Grad-iFrac System using Sephadex G-50 superfine. The purity of hEGF and the total yield were more than 94% and higher than 36%, respectively, and SDS-PAGE of the purified hEGF demonstrated a single band corresponding to an hEGF standard. In particular, a very important phenomenon was found, i.e. that the amount of heterogenous protein in fermentation broths cultured in media with high concentrations of lactose is far less than that cultured in media with high concentrations of glucose.
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Affiliation(s)
- W Y Tong
- Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou, People's Republic of China
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17
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Katayama Y, Tajiri H, Tada K, Okada S, Tong WY, Ishido S, Hotta H. Follow-up study of hypervariable region sequences of the hepatitis C virus (HCV) genome in an infant with delayed anti-HCV antibody responses. Microbiol Immunol 1998; 42:75-9. [PMID: 9525785 DOI: 10.1111/j.1348-0421.1998.tb01974.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An infant born prematurely and infected with hepatitis C virus (HCV) one month after birth was followed for 4.5 years. The patient did not produce detectable anti-HCV antibodies until two years after the onset of hepatitis. Before seroconversion, a single clone of HCV, as determined by quasispecies of the hypervariable region (HVR) of the HCV genome, was almost exclusively found in the serum. After seroconversion, however, another distinct lineage of HCV clones replaced it within half a year. As HCV infection persisted further in the presence of anti-HCV antibodies, many derivatives of both sequence lineages emerged to exhibit the typical quasispecies feature of HVR sequences. Neither seroconversion nor the changes in HVR sequences influenced the serum aminotransferase titers.
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Affiliation(s)
- Y Katayama
- Department of Microbiology, Kobe University School of Medicine, Hyogo, Japan
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Ishido S, Muramatsu S, Fujita T, Iwanaga Y, Tong WY, Katayama Y, Itoh M, Hotta H. Wild-type, but not mutant-type, p53 enhances nuclear accumulation of the NS3 protein of hepatitis C virus. Biochem Biophys Res Commun 1997; 230:431-6. [PMID: 9016797 DOI: 10.1006/bbrc.1996.5980] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
By using vaccinia virus-T7 hybrid expression system, subcellular localization of the NS3 protein of hepatitis C virus was studied. Full-size NS3 (NS3F) and a carboxy-terminally truncated form (NS3 deltaC) were localized in the cytoplasm and the nucleus when expressed alone. However, NS3F and NS3 deltaC, but not amino- and carboxy-terminally truncated form (NS3 deltaN deltaC), were each co-localized with wild-type p53 almost exclusively in the nucleus upon co-expression. The wild-type p53-induced nuclear accumulation of NS3F was inhibited only partially by NS4A. When co-expressed with mutant-type p53, NS3F and NS3 deltaC were each co-localized with it exclusively in the cytoplasm. Taken together, the present results suggest that wild-type p53 enhances nuclear accumulation of NS3F and NS3 deltaC through the involvement of their amino-terminal sequences even in the presence of NS4A, and that mutant-type p53 inhibits their nuclear, and enhances their cytoplasmic, accumulation.
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Affiliation(s)
- S Ishido
- Department of Microbiology, Kobe University School of Medicine, Chuo-ku, Hyogo, Japan
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