1
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Chen S, Imran S, Zhao Y, Zhu J. Probing the Limit of the Number of Saturated Atoms for Achieving Hyperconjugative Aromaticity. Inorg Chem 2024. [PMID: 39014904 DOI: 10.1021/acs.inorgchem.4c02050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2024]
Abstract
Aromaticity is a fundamental concept in organic chemistry. Hyperconjugative aromaticity, also known as hyperconjugation-induced aromaticity, has evolved from its origin from main group substituents to transition metal analogues, establishing itself as an important category of aromaticity. Additionally, aromatic compounds comprising two sp3-carbon atoms have recently been reported both experimentally and computationally. However, what is the maximum number of sp3-hybridized atoms needed to maintain hyperconjugative aromaticity? Here, we report that hyperconjugative aromaticity can be achieved in hexa-substituted indoliums and octa-substituted pyrroliums, possessing three-five sp3-hybridized carbon/nitrogen atoms by means of density functional theory (DFT) calculations. The aromaticity was confirmed by using various aromaticity indices, i.e., NICS, MCI, and EDDB. Notably, the strong electron-donating ability and aurophilicity of Au(I) substituents play a pivotal role in maintaining the aromaticity and structural integrity. In addition, increasing the number of hyperconjugative centers will decrease the aromaticity in these five-membered rings. Our findings highlight the significance of transition metal substituents in hyperconjugative aromaticity and offer a novel approach for designing aromatic organometallics.
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Affiliation(s)
- Shuwen Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Sajid Imran
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong 518172, China
| | - Yu Zhao
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Jun Zhu
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong 518172, China
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2
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Ren X, Li H, Peng H, Yang Y, Su H, Huang C, Wang X, Zhang J, Liu Z, Wei W, Cheng K, Zhu T, Lu Z, Li Z, Zhao Q, Tang BZ, Yao SQ, Song X, Sun H. Reactivity-Tunable Fluorescent Platform for Selective and Biocompatible Modification of Cysteine or Lysine. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2402838. [PMID: 38896788 DOI: 10.1002/advs.202402838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 06/03/2024] [Indexed: 06/21/2024]
Abstract
Chemoselective modification of specific residues within a given protein poses a significant challenge, as the microenvironment of amino acid residues in proteins is variable. Developing a universal molecular platform with tunable chemical warheads can provide powerful tools for precisely labeling specific amino acids in proteins. Cysteine and lysine are hot targets for chemoselective modification, but current cysteine/lysine-selective warheads face challenges due to cross-reactivity and unstable reaction products. In this study, a versatile fluorescent platform is developed for highly selective modification of cysteine/lysine under biocompatible conditions. Chloro- or phenoxy-substituted NBSe derivatives effectively labeled cysteine residues in the cellular proteome with high specificity. This finding also led to the development of phenoxy-NBSe phototheragnostic for the diagnosis and activatable photodynamic therapy of GSH-overexpressed cancer cells. Conversely, alkoxy-NBSe derivatives are engineered to selectively react with lysine residues in the cellular environment, exhibiting excellent anti-interfering ability against thiols. Leveraging a proximity-driven approach, alkoxy-NBSe probes are successfully designed to demonstrate their utility in bioimaging of lysine deacetylase activity. This study also achieves integrating a small photosensitizer into lysine residues of proteins in a regioselective manner, achieving photoablation of cancer cells activated by overexpressed proteins.
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Affiliation(s)
- Xiaojie Ren
- Department of Chemistry and Centre of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, 999077, China
- College of Chemistry & Chemical Engineering, Central South University, Changsha, Hunan, 410083, China
| | - Haokun Li
- Department of Chemistry and Centre of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, 999077, China
| | - Hui Peng
- International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development (MOE), MOE Key Laboratory of Tumor Molecular Biology, School of Pharmacy, Jinan University, Guangzhou, Guangdong, 510632, China
| | - Yang Yang
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 999077, China
| | - Hang Su
- College of Chemistry & Chemical Engineering, Central South University, Changsha, Hunan, 410083, China
| | - Chen Huang
- Department of Chemistry and Centre of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, 999077, China
| | - Xuan Wang
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, 518107, China
| | - Jie Zhang
- Department of Chemistry and Centre of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, 999077, China
| | - Zhiyang Liu
- Department of Chemistry and Centre of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, 999077, China
| | - Wenyu Wei
- Department of Chemistry and Centre of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, 999077, China
| | - Ke Cheng
- Department of Chemistry and Centre of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, 999077, China
| | - Tianyang Zhu
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 999077, China
| | - Zhenpin Lu
- Department of Chemistry and Centre of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, 999077, China
| | - Zhengqiu Li
- International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development (MOE), MOE Key Laboratory of Tumor Molecular Biology, School of Pharmacy, Jinan University, Guangzhou, Guangdong, 510632, China
| | - Qian Zhao
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 999077, China
| | - Ben Zhong Tang
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, 999077, China
| | - Shao Q Yao
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
| | - Xiangzhi Song
- College of Chemistry & Chemical Engineering, Central South University, Changsha, Hunan, 410083, China
| | - Hongyan Sun
- Department of Chemistry and Centre of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, 999077, China
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3
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Lv X, Li C, Guo MM, Hong W, Chen LC, Zhang QC, Chen ZN. Hydroxyl Group as the 'Bridge' to Enhance the Single-Molecule Conductance by Hyperconjugation. Molecules 2024; 29:2440. [PMID: 38893316 PMCID: PMC11173964 DOI: 10.3390/molecules29112440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 05/17/2024] [Accepted: 05/20/2024] [Indexed: 06/21/2024] Open
Abstract
For designing single-molecule devices that have both conjugation systems and structural flexibility, a hyperconjugated molecule with a σ-π bond interaction is considered an ideal candidate. In the investigation of conductance at the single-molecule level, since few hyperconjugation systems have been involved, the strategy of building hyperconjugation systems and the mechanism of electron transport within this system remain unexplored. Based on the skipped-conjugated structure, we present a rational approach to construct a hyperconjugation molecule using a hydroxyl group, which serves as a bridge to interact with the conjugated fragments. The measurement of single-molecule conductance reveals a two-fold conductance enhancement of the hyperconjugation system having the 'bridging' hydroxyl group compared to hydroxyl-free derivatives. Theoretical studies demonstrate that the hydroxyl group in the hyperconjugation system connects the LUMO of the two conjugated fragments and opens a through-space channel for electron transport to enhance the conductance.
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Affiliation(s)
- Xin Lv
- Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China; (X.L.); (C.L.); (M.-M.G.); (Z.-N.C.)
- College of Chemistry and Materials Science, Fujian Normal University, Fuzhou 350007, China
- Fujian College, University of Chinese Academy of Sciences, Fuzhou 350002, China
| | - Chang Li
- Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China; (X.L.); (C.L.); (M.-M.G.); (Z.-N.C.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Meng-Meng Guo
- Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China; (X.L.); (C.L.); (M.-M.G.); (Z.-N.C.)
| | - Wenjing Hong
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China;
| | - Li-Chuan Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China;
| | - Qian-Chong Zhang
- Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China; (X.L.); (C.L.); (M.-M.G.); (Z.-N.C.)
- Fujian College, University of Chinese Academy of Sciences, Fuzhou 350002, China
- Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou 350108, China
| | - Zhong-Ning Chen
- Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China; (X.L.); (C.L.); (M.-M.G.); (Z.-N.C.)
- Fujian College, University of Chinese Academy of Sciences, Fuzhou 350002, China
- Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou 350108, China
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4
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Novotný J, Munzarová M, Marek R. Mechanisms of Ligand Hyperfine Coupling in Transition-Metal Complexes: σ and π Transmission Pathways. Inorg Chem 2024; 63:8580-8592. [PMID: 38690843 PMCID: PMC11094796 DOI: 10.1021/acs.inorgchem.3c04425] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 03/27/2024] [Accepted: 03/29/2024] [Indexed: 05/03/2024]
Abstract
Theoretical interpretation of hyperfine interactions was pioneered in the 1950s-1960s by the seminal works of McConnell, Karplus, and others for organic radicals and by Watson and Freeman for transition-metal (TM) complexes. In this work, we investigate a series of octahedral Ru(III) complexes with aromatic ligands to understand the mechanism of transmission of the spin density from the d-orbital of the metal to the s-orbitals of the ligand atoms. Spin densities and spin populations underlying ligand hyperfine couplings are analyzed in terms of π-conjugative or σ-hyperconjugative delocalization vs spin polarization based on symmetry considerations and restricted open-shell vs unrestricted wave function analysis. The transmission of spin density is shown to be most efficient in the case of symmetry-allowed π-conjugative delocalization, but when the π-conjugation is partially or fully symmetry-forbidden, it can be surpassed by σ-hyperconjugative delocalization. Despite a lower spin population of the ligand in σ-hyperconjugative transmission, the hyperfine couplings can be larger because of the direct involvement of the ligand s-orbitals in this delocalization pathway. We demonstrate a quantitative correlation between the hyperfine couplings of aromatic ligand atoms and the characteristics of the metal-ligand bond modulated by the trans substituent, a hyperfine trans effect.
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Affiliation(s)
- Jan Novotný
- CEITEC
− Central European Institute of Technology, Masaryk University, Kamenice 5, Brno CZ-62500, Czechia
- Department
of Chemistry, Faculty of Science, Masaryk
University, Kamenice
5, Brno CZ-62500, Czechia
| | - Markéta Munzarová
- Department
of Chemistry, Faculty of Science, Masaryk
University, Kamenice
5, Brno CZ-62500, Czechia
| | - Radek Marek
- CEITEC
− Central European Institute of Technology, Masaryk University, Kamenice 5, Brno CZ-62500, Czechia
- Department
of Chemistry, Faculty of Science, Masaryk
University, Kamenice
5, Brno CZ-62500, Czechia
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5
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Clover A, Jones AP, Berger RF, Kaminsky W, O’Neil GW. Regioselective Fluorohydrin Synthesis from Allylsilanes and Evidence for a Silicon-Fluorine Gauche Effect. J Org Chem 2024; 89:4309-4318. [PMID: 38457664 PMCID: PMC11002936 DOI: 10.1021/acs.joc.3c02163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 02/20/2024] [Accepted: 02/26/2024] [Indexed: 03/10/2024]
Abstract
Allylsilanes can be regioselectively transformed into the corresponding 3-silylfluorohydrin in good yield using a sequence of epoxidation followed by treatment with HF·Et3N with or without isolation of the intermediate epoxide. Various silicon-substitutions are tolerated, resulting in a range of 2-fluoro-3-silylpropan-1-ol products from this method. Whereas other fluorohydrin syntheses by epoxide opening using HF·Et3N generally require more forcing conditions (e.g., higher reaction temperature), opening of allylsilane-derived epoxides with this reagent occurs at room temperature. We attribute this rate acceleration along with the observed regioselectivity to a β-silyl effect that stabilizes a proposed cationic intermediate. The use of enantioenriched epoxides indicates that both SN1- and SN2-type mechanisms may be operable depending on substitution at silicon. Conformational analysis by NMR and theory along with a crystal structure obtained by X-ray diffraction points to a preference for silicon and fluorine to be proximal to one another in the products, perhaps favored due to electrostatic interactions.
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Affiliation(s)
- Alexie
W. Clover
- Department
of Chemistry, Western Washington University, Bellingham, Washington 98229, United States
| | - Adam P. Jones
- Department
of Chemistry, Western Washington University, Bellingham, Washington 98229, United States
| | - Robert F. Berger
- Department
of Chemistry, Western Washington University, Bellingham, Washington 98229, United States
| | - Werner Kaminsky
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Gregory. W. O’Neil
- Department
of Chemistry, Western Washington University, Bellingham, Washington 98229, United States
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6
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Francisco CB, Fernandes CDS, Franco Dourado F, Gauze GDF, Rittner R, Prosser RS, Basso EA. Conformational Landscape of α-Halopropiophenones Determined by nJC-H NMR Reveals Unexpected Patterns and Geometric Constraints. J Phys Chem A 2024; 128:1566-1575. [PMID: 38412415 DOI: 10.1021/acs.jpca.3c06934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
The conformational features of α-halopropiophenones were investigated to understand the influence of α-halogens on conformation through hyperconjugative interactions, electrostatics, and steric factors. Using NMR, C-H scalar coupling constants were measured in different solvents, revealing a pattern in the conformational equilibria, which we validated by computational means. This behavior arises largely from hyperconjugative effects with the exception of the fluoro-derivatives, which are also influenced by steric and electrostatic interactions. In all cases, the contribution to hyperconjugation of the α-halo ketones is driven by the oxygen lone pair (rather than the C-X bond), which donates electron density to the adjacent C-C bonds. Additionally, C-Cα bond rotation generates distortions in the side chain, responsible for destabilization, thus affecting system conjugation. These structural features identified for the α-halo ketones are also reflected in their reactivity, which is distinct from that expected for nucleophilic addition.
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Affiliation(s)
- Camila Botin Francisco
- Department of Chemistry, State University of Maringá, 5790, Maringá 87020-900, Brazil
- Department of Chemistry, University of Toronto, 3359, Mississauga L5L-1C6, Canada
| | | | | | | | - Roberto Rittner
- Chemistry Institute, University of Campinas, 6154, Campinas 13083-970, Brazil
| | - Robert Scott Prosser
- Department of Chemistry, University of Toronto, 3359, Mississauga L5L-1C6, Canada
| | - Ernani Abicht Basso
- Department of Chemistry, State University of Maringá, 5790, Maringá 87020-900, Brazil
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7
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Caceres-Martinez LE, Kilaz G. Kinematic viscosity prediction of jet fuels and alternative blending components via comprehensive two-dimensional gas chromatography, partial least squares, and Yeo-Johnson transformation. J Sep Sci 2024; 47:e2300816. [PMID: 38471968 DOI: 10.1002/jssc.202300816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 01/28/2024] [Accepted: 01/30/2024] [Indexed: 03/14/2024]
Abstract
This work presents an accurate yet simplified partial least squares model to predict the kinematic viscosity of conventional and alternative jet fuels at -20°C using comprehensive two-dimensional gas chromatography coupled to a flame ionization detector (GC × GC/FID). Three different normalization methods (mean-centering, logarithmic, and Yeo-Johnson) were evaluated to identify their impact in the prediction of middle distillates' physical properties. Results using Yeo-Johnson transformation exhibited improved viscosity prediction capabilities over the validation set with a mean absolute percentage error of 5.3%, a root-mean-squared error of 0.23, and a coefficient of determination (R2 ) of 0.9404 using only 10 latent variables. Unlike previously reported correlations, this model allowed the identification of specific hydrocarbon groups and carbon numbers that drive jet fuel viscosity at low temperatures. The presence of even small amounts of large branched-alkanes (C15 -C17 ), dicyclic-alkanes (C10 ), and cycloaromatics (C11 ) have the potential to strongly increase the kinematic viscosity of jet fuels. Contrastingly, light monocycloalkanes and branched-alkanes (≤ C10 ) were associated with lower viscosity values. Novelly, this model suggests the implementation of Yeo-Johnson transformations to predict the physical properties of middle distillates to further improve the performance metrics of partial least squares models based on GC data.
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Affiliation(s)
| | - Gozdem Kilaz
- School of Engineering Technology, Purdue University, West Lafayette, Indiana, USA
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8
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Zou Y, Yu F, Liu X, Zu L. CH 3O Substitution Effect Revisited in the Vibrationally Resolved Laser-Induced Fluorescence Spectra of Methoxycyclohexoxy Radicals. J Phys Chem A 2024; 128:1025-1031. [PMID: 38301214 DOI: 10.1021/acs.jpca.3c07154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
The oxy-substituted alkoxy radicals have attracted wide attention due to the increasing application of oxygenated volatile organic compounds as fuel additives and solvents. Direct detection of these intermediate radicals is desired for measuring the reaction rate and investigating the oxidation mechanism of organic compounds in the atmosphere. A charge-transfer excited state induced by CH3O substitution was identified in our previous study of 3-methoxy-1-propoxy radical [Xue, J. Phys. Chem. Chem. Phys. 2021, 23, 2586]. As the C-C bonds of chain alkoxy radicals can freely rotate, further studies are needed to understand the mechanism of this long-range charge-transfer effect. In this work, vibrational-resolved laser-induced fluorescence (LIF) spectra of 3- and 4-methoxycyclohexoxy radicals were obtained under jet-cooled conditions. A large red-shift of ∼454 cm-1 of the origin band was observed when the CH3O substituent moved from the δ site to the γ site of the cyclohexoxy radical. The LIF spectra are assigned to 3-cis (e, e) and 4-trans (e, e) conformers, respectively, with the assistance of structural optimization and electron excitation studies conducted at the CAM-B3LYP/6-311++G(d,p) level of theory. Natural transition orbital analysis reveals that the intramolecular charge transfer from the C-O-C p orbital to the radical O p orbital in 3-methoxycyclohexoxy has a strong effect on the radical CO σ → O p excitation and hence results in a spectral change. On the other hand, the spectral effect of CH3O substitution almost vanishes at δ carbon. The results propose a through-bond interaction between CH3O and radical CO groups.
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Affiliation(s)
- Yizhen Zou
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Fengming Yu
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Xiaoyu Liu
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Lily Zu
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
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9
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Medina Rivero S, Alonso-Navarro MJ, Tonnelé C, Marín-Beloqui JM, Suárez-Blas F, Clarke TM, Kang S, Oh J, Ramos MM, Kim D, Casanova D, Segura JL, Casado J. V-Shaped Tröger Oligothiophenes Boost Triplet Formation by CT Mediation and Symmetry Breaking. J Am Chem Soc 2023; 145:27295-27306. [PMID: 38060544 PMCID: PMC10839832 DOI: 10.1021/jacs.3c06916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 11/08/2023] [Accepted: 11/17/2023] [Indexed: 12/21/2023]
Abstract
A new family of molecules obtained by coupling Tröger's base unit with dicyanovinylene-terminated oligothiophenes of different lengths has been synthesized and characterized by steady-state stationary and transient time-resolved spectroscopies. Quantum chemical calculations allow us to interpret and recognize the properties of the stationary excited states as well as the time-dependent mechanisms of singlet-to-triplet coupling. The presence of the diazocine unit in Tröger's base derivatives is key to efficiently producing singlet-to-triplet intersystem crossing mediated by the role of the nitrogen atoms and of the almost orthogonal disposition of the two thiophene arms. Spin-orbit coupling-mediated interstate intersystem crossing (ISC) is activated by a symmetry-breaking process in the first singlet excited state with partial charge transfer character. This mechanism is a characteristic of these molecular triads since the independent dicyanovinylene-oligothiophene branches do not display appreciable ISC. These results show how Tröger's base coupling of organic chromophores can be used to improve the ISC efficiency and tune their photophysics.
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Affiliation(s)
- Samara Medina Rivero
- Department
of Physical Chemistry, Faculty of Science, University of Málaga, 29071 Málaga, Spain
- Department
of Physics and Astronomy, University of
Sheffield, Sheffield S3 7RH, United Kingdom
| | - Matías J. Alonso-Navarro
- Organic
Chemistry Department, Faculty of Chemistry, Complutense University of Madrid, 28040 Madrid, Spain
- Chemical
and Environmental Technology Department, Rey Juan Carlos University, 28933 Madrid, Spain
| | - Claire Tonnelé
- Donostia
International Physics Center (DIPC), 20018 Donostia, Euskadi, Spain
- Ikerbasque
Foundation for Science, 48009 Bilbao, Euskadi, Spain
| | - Jose M. Marín-Beloqui
- Department
of Physical Chemistry, Faculty of Science, University of Málaga, 29071 Málaga, Spain
| | - Fátima Suárez-Blas
- Organic
Chemistry Department, Faculty of Chemistry, Complutense University of Madrid, 28040 Madrid, Spain
- Chemical
and Environmental Technology Department, Rey Juan Carlos University, 28933 Madrid, Spain
| | - Tracey M. Clarke
- Department
of Chemistry, University College London, London WC1H 0AJ, U.K.
| | - Seongsoo Kang
- Department
of Chemistry, Yonsei University, Seoul 03722, Korea
| | - Juwon Oh
- Department
of Chemistry, Soonchunhyang University, Asan 31538, Korea
| | - M. Mar Ramos
- Chemical
and Environmental Technology Department, Rey Juan Carlos University, 28933 Madrid, Spain
| | - Dongho Kim
- Department
of Chemistry, Yonsei University, Seoul 03722, Korea
- Division
of Energy Materials, Pohang University of
Science and Technology (POSTECH), Pohang 37673, Korea
| | - David Casanova
- Donostia
International Physics Center (DIPC), 20018 Donostia, Euskadi, Spain
- Ikerbasque
Foundation for Science, 48009 Bilbao, Euskadi, Spain
| | - José L. Segura
- Organic
Chemistry Department, Faculty of Chemistry, Complutense University of Madrid, 28040 Madrid, Spain
| | - Juan Casado
- Department
of Physical Chemistry, Faculty of Science, University of Málaga, 29071 Málaga, Spain
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10
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Pandey AK, Ganguly HK, Sinha SK, Daniels KE, Yap GPA, Patel S, Zondlo NJ. An Inherent Difference between Serine and Threonine Phosphorylation: Phosphothreonine Strongly Prefers a Highly Ordered, Compact, Cyclic Conformation. ACS Chem Biol 2023; 18:1938-1958. [PMID: 37595155 DOI: 10.1021/acschembio.3c00068] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/20/2023]
Abstract
Phosphorylation and dephosphorylation of proteins by kinases and phosphatases are central to cellular responses and function. The structural effects of serine and threonine phosphorylation were examined in peptides and in proteins, by circular dichroism, NMR spectroscopy, bioinformatics analysis of the PDB, small-molecule X-ray crystallography, and computational investigations. Phosphorylation of both serine and threonine residues induces substantial conformational restriction in their physiologically more important dianionic forms. Threonine exhibits a particularly strong disorder-to-order transition upon phosphorylation, with dianionic phosphothreonine preferentially adopting a cyclic conformation with restricted ϕ (ϕ ∼ -60°) stabilized by three noncovalent interactions: a strong intraresidue phosphate-amide hydrogen bond, an n → π* interaction between consecutive carbonyls, and an n → σ* interaction between the phosphate Oγ lone pair and the antibonding orbital of C-Hβ that restricts the χ2 side-chain conformation. Proline is unique among the canonical amino acids for its covalent cyclization on the backbone. Phosphothreonine can mimic proline's backbone cyclization via noncovalent interactions. The preferred torsions of dianionic phosphothreonine are ϕ,ψ = polyproline II helix > α-helix (ϕ ∼ -60°); χ1 = g-; χ2 ∼ +115° (eclipsed C-H/O-P bonds). This structural signature is observed in diverse proteins, including in the activation loops of protein kinases and in protein-protein interactions. In total, these results suggest a structural basis for the differential use and evolution of threonine versus serine phosphorylation sites in proteins, with serine phosphorylation typically inducing smaller, rheostat-like changes, versus threonine phosphorylation promoting larger, step function-like switches, in proteins.
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Affiliation(s)
- Anil K Pandey
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Himal K Ganguly
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Sudipta Kumar Sinha
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
- Department of Chemistry, Indian Institute of Technology Ropar, Nangal Road, Rupnagar 140001, India
| | - Kelly E Daniels
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Glenn P A Yap
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Sandeep Patel
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Neal J Zondlo
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
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11
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Chabuka BK, Alabugin IV. Hole Catalysis of Cycloaddition Reactions: How to Activate and Control Oxidant Upconversion in Radical-Cationic Diels-Alder Reactions. J Am Chem Soc 2023; 145:19354-19367. [PMID: 37625247 DOI: 10.1021/jacs.3c06106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/27/2023]
Abstract
In order to use holes as catalysts, the oxidized product should be able to transfer the hole to a fresh reactant. For that, the hole-catalyzed reaction must increase the oxidation potential along the reaction path, i.e., lead to "hole upconversion." If this thermodynamic requirement is satisfied, a hole injected via one-electron oxidation can persist through multiple propagation cycles and serve as a true catalyst. This work provides guidelines for the rational design of hole-catalyzed Diels-Alder (DA) reactions, the prototypical cycloaddition. After revealing the crucial role of hyperconjugation in the absence of hole upconversion in the parent DA reaction, we show how upconversion can be reactivated by proper substitution. For this purpose, we computationally evaluate the contrasting effects of substituents at the three possible positions in the two reactants. The occurrence and magnitude of hole upconversion depend strongly on the placement and nature of substituents. For example, donors at C1 in 1,3-butadiene shift the reaction to the hole-upconverted regime with an increased oxidation potential of up to 1.0 V. In contrast, hole upconversion in C2-substituted 1,3-butadienes is activated by acceptors with the oxidation potential increase up to 0.54 V. Dienophile substitution results in complex trends because the radical cation can be formed at either the dienophile or the diene. Hole upconversion is always present in the former scenario (up to 0.65 V). Finally, we report interesting stereoelectronic effects that can activate or deactivate upconversion via a conformational change.
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Affiliation(s)
- Beauty K Chabuka
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Igor V Alabugin
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
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12
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Owen AN, Esselman BJ, Woods RC, McMahon RJ. Carbon Condensation via [4 + 2] Cycloaddition of Highly Unsaturated Carbon Chains. J Phys Chem A 2023; 127:4277-4290. [PMID: 37146283 DOI: 10.1021/acs.jpca.3c00617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We present computational studies of reaction pathways for alkyne/polyyne dimerization that represent plausible early steps in mechanisms for carbon condensation. A previous computational study of the ring coalescence and annealing model of C60 formation revealed that a 1,4-didehydrobenzocyclobutadiene intermediate (p-benzyne derivative) has little to no barrier to undergoing an unproductive retro-Bergman cyclization, which brings into question the relevance of that reaction pathway. The current study investigates an alternative model, which proceeds through an initial [4 + 2] cycloaddition instead of a [2 + 2] cycloaddition. In this pathway, the problematic intermediate is avoided, with the reaction proceeding via a (potentially) more kinetically stable tetradehydronaphthalene derivative. The computational studies of the [2 + 2] and [4 + 2] model systems, with increasing alkyne substitutions, reveal that the para-benzyne diradical of the [4 + 2] pathway has a significantly greater barrier to ring opening than the analogous intermediates of the [2 + 2] pathway and that alkyne substitution has little effect on this important barrier. These studies employ spin-flip, time-dependent density functional theory (SF-TDDFT) to provide suitable treatment of open-shell diradical intermediates.
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Affiliation(s)
- Andrew N Owen
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Brian J Esselman
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - R Claude Woods
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Robert J McMahon
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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13
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Karadakov PB, Riley T. The Effect of Hydrogenation on the Contest between Aromaticity and Antiaromaticity in Norcorrole. Chemistry 2023; 29:e202203400. [PMID: 36436122 DOI: 10.1002/chem.202203400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 11/22/2022] [Accepted: 11/22/2022] [Indexed: 11/29/2022]
Abstract
Magnetic shielding studies demonstrate that successive hydrogenation of NiII norcorrole (NiNc), a stable molecule combining aromatic and antiaromatic features, first weakens and then eliminates the central antiaromatic region, even though the NiNc antiaromatic "core", a 14-membered conjugated cycle with 16 π electrons, is formally preserved throughout the H2 NiNc-H8 NiNc series. The differences between aromatic and non-aromatic isotropic shielding distributions and nucleus-independent chemical shift (NICS) values in these hydrogenated porphyrin analogues are highlighted by comparing the results for the members of the H2 NiNc-H8 NiNc series to those for the aromatic NiII porphyrin complex. The results strongly support the unexpected and counterintuitive conclusion that H8 NiNc will be nonaromatic, without even a trace of antiaromaticity. Based on these findings, H8 NiNc is predicted to be the most stable member of the H2 NiNc-H8 NiNc series.
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Affiliation(s)
- Peter B Karadakov
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK
| | - Tom Riley
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK
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14
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Popovici I, Barthes C, Tannoux T, Duhayon C, Casaretto N, Monari A, Auffrant A, Canac Y. Phosphonium Ylides vs Iminophosphoranes: The Role of the Coordinating Ylidic Atom in cis-[Phosphine-Ylide Rh(CO) 2] Complexes. Inorg Chem 2023; 62:2376-2388. [PMID: 36704899 DOI: 10.1021/acs.inorgchem.2c04151] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The coordinating properties of two families of ylides, namely, phosphonium ylides and iminophosphoranes, differently substituted at the ylidic center (CH2- vs NiPr-), have been investigated in structurally related cationic phosphine-ylide Rh(CO)2 complexes obtained from readily available phosphine-phosphonium salt precursors derived from an ortho-phenylene bridge. However, while the Rh(CO)2 complex bearing the P+-CH2- donor moiety proved to be stable, the P═NiPr donor end appeared to induce lability to one of the CO groups. All of the RhI carbonyl complexes in both ylide series were fully characterized, including through X-ray diffraction analysis. Based on the experimental and calculated infrared (IR) CO stretching frequencies in Rh(CO)2 complexes, we evidenced that the phosphonium ylide ligand is a stronger donor than the iminophosphorane ligand. However, we also found that the difference in the intrinsic electronic properties can be largely compensated by the introduction of an iPr substituent on the N atom of the iminophosphorane, hence pointing to the noninnocent role of the peripheral substituent and opening novel possibilities to tune the properties of metal complexes containing ylide ligands.
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Affiliation(s)
- Ingrid Popovici
- Laboratoire de Chimie Moléculaire (LCM), CNRS, École Polytechnique, Institut Polytechnique de Paris, Route de Saclay, 91120 Palaiseau, France
| | - Cécile Barthes
- LCC-CNRS, Université de Toulouse, CNRS, 205 route de Narbonne, 31077 Toulouse Cedex 4, France
| | - Thibault Tannoux
- Laboratoire de Chimie Moléculaire (LCM), CNRS, École Polytechnique, Institut Polytechnique de Paris, Route de Saclay, 91120 Palaiseau, France
| | - Carine Duhayon
- LCC-CNRS, Université de Toulouse, CNRS, 205 route de Narbonne, 31077 Toulouse Cedex 4, France
| | - Nicolas Casaretto
- Laboratoire de Chimie Moléculaire (LCM), CNRS, École Polytechnique, Institut Polytechnique de Paris, Route de Saclay, 91120 Palaiseau, France
| | - Antonio Monari
- ITODYS, Université Paris Cité and CNRS, F-75006 Paris, France
| | - Audrey Auffrant
- Laboratoire de Chimie Moléculaire (LCM), CNRS, École Polytechnique, Institut Polytechnique de Paris, Route de Saclay, 91120 Palaiseau, France
| | - Yves Canac
- LCC-CNRS, Université de Toulouse, CNRS, 205 route de Narbonne, 31077 Toulouse Cedex 4, France
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15
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León Rayo DF, Mansour A, Wu W, Bhawal BN, Gagosz F. Steric, Electronic and Conformational Synergistic Effects in the Gold(I)-catalyzed α-C-H Bond Functionalization of Tertiary Amines. Angew Chem Int Ed Engl 2023; 62:e202212893. [PMID: 36170553 DOI: 10.1002/anie.202212893] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Indexed: 01/12/2023]
Abstract
Direct C-H bond functionalization is a useful strategy for the straightforward formation of C-C and C-Heteroatom bonds. In the present work, a unique approach for the challenging electrophilic Au-catalyzed α-C-H bond functionalization of tertiary amines is presented. Electronic, steric and conformational synergistic effects exerted by the use of a malonate unit in the substrate were key to the success of this transformation. This new reactivity was applied to the synthesis of tetrahydro-γ-carboline products which, under oxidative conditions, could be converted into valuable structural motifs found in bioactive alkaloid natural products.
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Affiliation(s)
- David F León Rayo
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, K1N 6N5, Ottawa, Canada
| | - Ali Mansour
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, K1N 6N5, Ottawa, Canada
| | - Wenbin Wu
- Département de Chimie, UMR 7652 CNRS, Ecole Polytechnique, 91128, Palaiseau, France
| | - Benjamin N Bhawal
- Département de Chimie, UMR 7652 CNRS, Ecole Polytechnique, 91128, Palaiseau, France.,Present Address: EaStChem, School of Chemistry, University of Edinburgh Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, UK
| | - Fabien Gagosz
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, K1N 6N5, Ottawa, Canada.,Département de Chimie, UMR 7652 CNRS, Ecole Polytechnique, 91128, Palaiseau, France
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16
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Ureel Y, Vermeire FH, Sabbe MK, Van Geem KM. Ab Initio Group Additive Values for Thermodynamic Carbenium Ion Property Prediction. Ind Eng Chem Res 2022. [DOI: 10.1021/acs.iecr.2c03597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Yannick Ureel
- Laboratory for Chemical Technology, Department of Materials, Textiles and Chemical Engineering, Ghent University, Technologiepark 125, 9052Gent, Belgium
| | - Florence H. Vermeire
- Laboratory for Chemical Technology, Department of Materials, Textiles and Chemical Engineering, Ghent University, Technologiepark 125, 9052Gent, Belgium
| | - Maarten K. Sabbe
- Laboratory for Chemical Technology, Department of Materials, Textiles and Chemical Engineering, Ghent University, Technologiepark 125, 9052Gent, Belgium
| | - Kevin M. Van Geem
- Laboratory for Chemical Technology, Department of Materials, Textiles and Chemical Engineering, Ghent University, Technologiepark 125, 9052Gent, Belgium
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17
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Rosenberg M, Brinker UH. Carbene Routes to Cyclopropatetrahedrane. J Org Chem 2022; 87:16902-16906. [PMID: 36446051 PMCID: PMC9764353 DOI: 10.1021/acs.joc.2c02217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Indexed: 11/30/2022]
Abstract
The formation of cyclopropatetrahedrane (tetracyclo[2.1.0.01,3.02,4]pentane) via four different carbene reactions is computed using the (U)CCSD(T)(full)/cc-pVTZ//(U)ωB97X-D/cc-pVTZ + 1.3686(EZPVE) theoretical model. Intrinsic reaction coordinate plots confirm that each carbene is directly linked to cyclopropatetrahedrane via a unique cyclopropanation step. Each elementary step is assessed according to the structure and energy of its transition state.
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Affiliation(s)
- Murray
G. Rosenberg
- Department
of Chemistry, The State University of New
York at Binghamton, P.O. Box 6000, Binghamton, New York 13902-6000, United States
| | - Udo H. Brinker
- Institute
of Organic Chemistry, University of Vienna, Währinger Strasse 38, 1090 Vienna, Austria
- Department
of Chemistry, The State University of New
York at Binghamton, P.O. Box 6000, Binghamton, New York 13902-6000, United States
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18
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Kraemer Y, Ghiazza C, Ragan AN, Ni S, Lutz S, Neumann EK, Fettinger JC, Nöthling N, Goddard R, Cornella J, Pitts CR. Strain-Release Pentafluorosulfanylation and Tetrafluoro(aryl)sulfanylation of [1.1.1]Propellane: Reactivity and Structural Insight. Angew Chem Int Ed Engl 2022; 61:e202211892. [PMID: 36137228 PMCID: PMC9828730 DOI: 10.1002/anie.202211892] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Indexed: 01/12/2023]
Abstract
We leveraged the recent increase in synthetic accessibility of SF5 Cl and Ar-SF4 Cl compounds to combine chemistry of the SF5 and SF4 Ar groups with strain-release functionalization. By effectively adding SF5 and SF4 Ar radicals across [1.1.1]propellane, we accessed structurally unique bicyclopentanes, bearing two distinct elements of bioisosterism. Upon evaluating these "hybrid isostere" motifs in the solid state, we measured exceptionally short transannular distances; in one case, the distance rivals the shortest nonbonding C⋅⋅⋅C contact reported to date. This prompted SC-XRD and DFT analyses that support the notion that a donor-acceptor interaction involving the "wing" C-C bonds is playing an important role in stabilization. Thus, these heretofore unknown structures expand the palette for highly coveted three-dimensional fluorinated building blocks and provide insight to a more general effect observed in bicyclopentanes.
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Affiliation(s)
- Yannick Kraemer
- Department of ChemistryUniversity of California, Davis1 Shields AvenueDavisCA 95616USA
| | - Clément Ghiazza
- Max-Planck-Institut für KohlenforschungKaiser-Wilhelm-Platz 145470Mülheim an der RuhrGermany
| | - Abbey N. Ragan
- Department of ChemistryUniversity of California, Davis1 Shields AvenueDavisCA 95616USA
| | - Shengyang Ni
- Max-Planck-Institut für KohlenforschungKaiser-Wilhelm-Platz 145470Mülheim an der RuhrGermany
| | - Sigrid Lutz
- Max-Planck-Institut für KohlenforschungKaiser-Wilhelm-Platz 145470Mülheim an der RuhrGermany
| | - Elizabeth K. Neumann
- Department of ChemistryUniversity of California, Davis1 Shields AvenueDavisCA 95616USA
| | - James C. Fettinger
- Department of ChemistryUniversity of California, Davis1 Shields AvenueDavisCA 95616USA
| | - Nils Nöthling
- Max-Planck-Institut für KohlenforschungKaiser-Wilhelm-Platz 145470Mülheim an der RuhrGermany
| | - Richard Goddard
- Max-Planck-Institut für KohlenforschungKaiser-Wilhelm-Platz 145470Mülheim an der RuhrGermany
| | - Josep Cornella
- Max-Planck-Institut für KohlenforschungKaiser-Wilhelm-Platz 145470Mülheim an der RuhrGermany
| | - Cody Ross Pitts
- Department of ChemistryUniversity of California, Davis1 Shields AvenueDavisCA 95616USA
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19
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Chen S, Zhu J. Probing the Hyperconjugative Aromaticity of Cyclopentadiene and Pyrroliums Containing Group 7 Transition Metal Substituents. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Shuwen Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Jun Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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20
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Malek B, Lu W, Mohapatra PP, Walalawela N, Jabeen S, Liu J, Greer A. Probing the Transition State-to-Intermediate Continuum: Mechanistic Distinction between a Dry versus Wet Perepoxide in the Singlet Oxygen "Ene" Reaction at the Air-Water Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:6036-6048. [PMID: 35506607 DOI: 10.1021/acs.langmuir.2c00279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
A mechanistic study is reported for the reactions of singlet oxygen (1O2) with alkene surfactants of tunable properties. Singlet oxygen was generated either top-down (photochemically) by delivery as a gas to an air-water interface or bottom-up (chemically) by transport to the air-water interface as a solvated species. In both cases, reactions were carried out in the presence of 7-carbon (7C), 9-carbon (9C), or 11-carbon (11C) prenylsurfactants [(CH3)2C═CH(CH2)nSO3- Na+ (n = 4, 6, 8)]. Higher "ene" hydroperoxide regioselectivities (secondary ROOH 2 to tertiary ROOH 3) were reached in delivering 1O2 top-down through air as compared to bottom-up via aqueous solution. In the photochemical reaction, ratios of 2:3 increased from 2.5:1 for 7C, to 2.8:1 for 9C, and to 3.2:1 for 11C. In contrast, in the bubbling system that generated 1O2 chemically, the selectivity was all but lost, ranging only from 1.3:1 to 1:1. The phase-dependent regioselectivities appear to be correlated with the "ene" reaction with photochemically generated, drier 1O2 at the air-water interface vs those with wetter 1O2 from the bubbling reactor. Density functional theory-calculated reaction potential energy surfaces (PESs) were used to help rationalize the reaction phase dependence. The reactions in the gas phase are mediated by perepoxide transition states with 32-41 kJ/mol binding energy for C═C(π)···1O2. The perepoxide species, however, evolve to well-defined stationary structures in the aqueous phase, with covalent C-O bonds and 85-88 kJ/mol binding energy. The combined experimental and computational evidence points to a unique mechanism for 1O2 "ene" tunability in a perepoxide continuum from a transition state to an intermediate.
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Affiliation(s)
- Belaid Malek
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, New York 11210, United States
| | - Wenchao Lu
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, United States
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, New York 10016, United States
| | - Prabhu Prasad Mohapatra
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, New York 11210, United States
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, New York 10016, United States
| | - Niluksha Walalawela
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, New York 11210, United States
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, New York 10016, United States
| | - Shakeela Jabeen
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, New York 11210, United States
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, New York 10016, United States
| | - Jianbo Liu
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, United States
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, New York 10016, United States
| | - Alexander Greer
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, New York 11210, United States
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, New York 10016, United States
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21
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D'mello VC, Goldsztejn G, Rao Mundlapati V, Brenner V, Gloaguen E, Charnay‐Pouget F, Aitken DJ, Mons M. Characterization of Asx Turn Types and Their Connate Relationship with β‐Turns. Chemistry 2022; 28:e202104328. [DOI: 10.1002/chem.202104328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Indexed: 11/11/2022]
Affiliation(s)
- Viola C. D'mello
- Université Paris-Saclay, CEA, CNRS Laboratoire Interactions Dynamiques et Lasers (LIDYL) 91191 Gif-sur-Yvette France
- Present address: Graphene Research Labs KIADB IT Park Near Airport Bengaluru 562149 India
| | - Gildas Goldsztejn
- Université Paris-Saclay, CEA, CNRS Laboratoire Interactions Dynamiques et Lasers (LIDYL) 91191 Gif-sur-Yvette France
- Present address: Université Paris-Saclay, CNRS Institut des Sciences Moléculaires d'Orsay (ISMO) 91405 Orsay France
| | - Venkateswara Rao Mundlapati
- Université Paris-Saclay, CEA, CNRS Laboratoire Interactions Dynamiques et Lasers (LIDYL) 91191 Gif-sur-Yvette France
- Present address: Institut de Recherche en Astrophysique et Planétologie (IRAP) Université de Toulouse (UPS), CNRS, CNES 9 Avenue du Colonel Roche 31028 Toulouse France
| | - Valérie Brenner
- Université Paris-Saclay, CEA, CNRS Laboratoire Interactions Dynamiques et Lasers (LIDYL) 91191 Gif-sur-Yvette France
| | - Eric Gloaguen
- Université Paris-Saclay, CEA, CNRS Laboratoire Interactions Dynamiques et Lasers (LIDYL) 91191 Gif-sur-Yvette France
| | - Florence Charnay‐Pouget
- Université Paris-Saclay, CNRS Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) 91405 Orsay France
- Present address: Université Clermont Auvergne, CNRS SIGMA Clermont, ICCF 63000 Clermont-Ferrand France
| | - David J. Aitken
- Université Paris-Saclay, CNRS Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO) 91405 Orsay France
| | - Michel Mons
- Université Paris-Saclay, CEA, CNRS Laboratoire Interactions Dynamiques et Lasers (LIDYL) 91191 Gif-sur-Yvette France
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22
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Bartolo ND, Demkiw KM, Read JA, Valentín EM, Yang Y, Dillon AM, Hu CT, Ward MD, Woerpel KA. Conformationally Biased Ketones React Diastereoselectively with Allylmagnesium Halides. J Org Chem 2022; 87:3042-3065. [PMID: 35167300 PMCID: PMC9022492 DOI: 10.1021/acs.joc.1c02844] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The addition of the highly reactive reagent allylmagnesium halide to α-substituted acyclic chiral ketones proceeded with high stereoselectivity. The stereoselectivity cannot be analyzed by conventional stereochemical models because these reactions do not conform to the requirements of those models. Instead, the stereoselectivity arises from the approach of the nucleophile to the most accessible diastereofaces of the lowest-energy conformations of the ketones. High stereoselectivity is expected, and the stereochemical outcome can be predicted, with conformationally biased ketones that have sterically distinguishable diastereofaces wherein only one face is accessible for nucleophilic addition. The conformations of the ketones can be determined by a combination of computational modeling and, in some cases, structure determination by X-ray crystallography.
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Affiliation(s)
- Nicole D. Bartolo
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY 10003 USA
| | - Krystyna M. Demkiw
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY 10003 USA
| | - Jacquelyne A. Read
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY 10003 USA
| | | | - Yingying Yang
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY 10003 USA
| | - Alexandra M. Dillon
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY 10003 USA
| | - Chunhua T. Hu
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY 10003 USA
| | - Michael D. Ward
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY 10003 USA
| | - K. A. Woerpel
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY 10003 USA
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23
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Laconsay CJ, Rho TC, Tantillo DJ. The Role of Through-Bond Stereoelectronic Effects in the Reactivity of 3-Azabicyclo[3.3.1]nonanes. J Org Chem 2022; 87:3378-3388. [PMID: 35191711 DOI: 10.1021/acs.joc.1c02992] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hyperconjugation/conjugation through-bond stereoelectronic effects were studied with density functional theory in the context of 3-azabicyclo[3.3.1]nonanes to unravel puzzling differences in reactivity between a vinylogous chloride (4) and a vinylogous ester (5). These compounds─whose structures differ only by one substituent─were found to display strikingly different reactivities in hydrochloric acid by Risch and co-workers ( J. Am. Chem. Soc., 1991, 113, 9411-9412). Computational analyses of substituent effects, noncovalent interactions, natural bond orbitals, isodesmic reactions, and hydration propensities lead to a model for which the role of remote, through-bond stereoelectronic effects is the key to explaining 4 and 5's diverging reactivity.
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Affiliation(s)
- Croix J Laconsay
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Tyler C Rho
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Dean J Tantillo
- Department of Chemistry, University of California, Davis, California 95616, United States
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24
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Fe3O4@SiO2@Methotrexate as efficient and nanomagnetic catalyst for the synthesis of 9-(aryl)thiazolo [4,5-d] [1,2,4]triazolo [1,5-a]pyrimidin-2(3H)-ones via a cooperative anomeric based oxidation: A joint experimental and computational mechanistic study. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2021.131769] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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25
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Martins FA, Chagas P, Thomasi SS, Oliveira LCA, Diniz R, Freitas MP. Theoretical and X-ray evidence of electrostatic phosphonium anti and gauche effects. Chemphyschem 2022; 23:e202100856. [PMID: 34995018 DOI: 10.1002/cphc.202100856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 12/21/2021] [Indexed: 11/12/2022]
Abstract
Sulfur, not phosphorus, is the only known third-row element capable of experiencing an electrostatic gauche effect with fluorine. Some six-membered rings containing an endocyclic phosphorus atom and a β-fluorine substituent that can interconvert to axial ( gauche relative to phosphorus) and equatorial positions were then analysed. While phosphines do not establish an electrostatic attraction between fluorine and phosphorus, some oxidised forms exhibit surprising stability for the sterically disfavoured axial orientation. Because the nature of this behaviour was not obvious, since an intramolecular hydrogen bond can appear, a phosphonium derivative was further studied and its axial conformation was found to be highly stable. A preference for the gauche arrangement appears even for the acyclic and sterically hindered (2-fluoroethyl)triphenylphosphonium cation. On the other hand, (ethane-1,2-diyl)bis(phosphonium) cations are exclusively in anti conformation due to an (+/+)-electrostatic repulsion between the positively charged phosphonium groups.
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Affiliation(s)
- Francisco A Martins
- Federal University of Lavras: Universidade Federal de Lavras, Chemistry, Av. Lagoa Azul, Casa, Lavras, 37200-900, Lavras, BRAZIL
| | | | - Sérgio S Thomasi
- Federal University of Lavras: Universidade Federal de Lavras, Chemistry, BRAZIL
| | | | - Renata Diniz
- Universidade Federal de Minas Gerais, Chemistry, BRAZIL
| | - Matheus P Freitas
- Federal University of Lavras, Department of Chemsitry, Campus UFLA, CP 3037, 37200-000, Lavras, BRAZIL
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26
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Torabi M, Zolfigol MA, Yarie M, Gu Y. Application of ammonium acetate as a dual rule reagent-catalyst in synthesis of new symmetrical terpyridines. MOLECULAR CATALYSIS 2021. [DOI: 10.1016/j.mcat.2021.111959] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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27
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Application of polyionic magnetic nanoparticles as a catalyst for the synthesis of carbonitriles with both indole and triazole moieties via a cooperative geminal-vinylogous anomeric-based oxidation. Mol Divers 2021; 26:2407-2426. [PMID: 34694532 DOI: 10.1007/s11030-021-10339-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 10/06/2021] [Indexed: 10/20/2022]
Abstract
Three-component reaction of aldehydes with 3-(1H-indol-3-yl)-3-oxopropanenitrile and 1H-1,2,4-triazol-5-amine under the solvent-free condition at 70 °C was effectively performed in the presence of 2 mg of polyionic magnetic nanoparticles with pyrazine bridge [Fe3O4@SiO2@(CH2)3]2-Pyrazinium-[TCM]2 as a catalyst for the synthesis of 7-aryl-5-(1H-indol-3-yl)-[1,2,4]triazolo[1,5-a]pyrimidine-6-carbonitriles via a cooperative anomeric-based oxidation. The polyionic magnetic nanoparticles catalyst was simply recovered and reused four successive runs. The morphology and structure of MNPs catalyst were investigated by numerous techniques such as XRD, FT-IR, EDX, WDX, FE-SEM, TEM, TGA, DTA, and VSM. The obtained products are reported for the first time that were identified by various analyses techniques such as melting point, FT-IR, 1H NMR, 13C NMR, and elemental analysis (CHN). A term entitled a cooperative geminal-vinylogous anomeric-based oxidation was introduced for the latter step of the reaction mechanism for the first time. Synthesis of 7-aryl-5-(1H-indol-3-yl)-[1,2,4]triazolo[1,5-a]pyrimidine-6-carbonitriles by using [Fe3O4@SiO2@(CH2)3]2-Pyrazinium-[TCM]2 MNPs as a catalyst.
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28
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Morisawa Y, Higaki Y, Ozaki Y. Far-Ultraviolet Spectroscopy and Quantum Chemical Calculation Studies of the Conformational Dependence on the Electronic Structure and Transitions of Cyclohexane, Methyl and Dimethyl Cyclohexane, and Decalin; Effects of Axial Substitutions on the Electronic Transitions. J Phys Chem A 2021; 125:8205-8214. [PMID: 34505772 DOI: 10.1021/acs.jpca.1c05688] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Far-ultraviolet (FUV) spectra were measured for cyclohexane, methyl cyclohexane, six isomers of dimethyl cyclohexane, and cis- and trans-decalin. Attenuated total reflection-FUV (ATR-FUV) spectroscopy, which we originally proposed, provides systematic information about the excitation states of saturated organic molecules and the hyperconjugation of σ bonds. The FUV spectra of cyclohexane and methyl cyclohexane in neat liquids showed a band with central wavelengths near 155 and 162 nm. The simulation spectrum of cyclohexane calculated by time-dependent density-functional theory (TD-DFT) (CAM-B3LYP/aug-cc-pVTZ) gives two bands at 146 and 152 nm owing to the transition from HOMO-2 to Rydberg 3pz (Tb) and those from HOMO and HOMO-1 to Rydberg 3px/3py (Ta), respectively. The simulation spectrum of methyl cyclohexane with the equatorial substituent has peaks at approximately the same positions as cyclohexane. The calculated molar absorption coefficient is larger than that of cyclohexane, estimating the observed FUV spectra very well. The FUV spectra of dimethyl cyclohexane with two methyl substituents at the equatorial positions (trans-1,2-, cis-1,3-, and trans-1,4-) and trans-decalin had similar features to those of cyclohexane and methylcyclohexane. The TD-DFT calculations revealed that the shoulders at the shorter- and longer-wavelength sides of the band center of dimethyl cyclohexane (with methyl substituents at equatorial positions) and trans-decalin are assigned to Tb and Ta, respectively. In the case of dimethyl cyclohexane with one methyl substituent in the axial position (cis-1,2-, trans-1,3-, and cis-1,4-) and cis-decalin, the band caused by Tb decreased compared to those of the other compounds. The decrease in intensity and the longer-wavelength shift of the Tb band for dimethyl cyclohexane (with one methyl group at the axial position) and cis-decalin revealed that the band on the longer-wavelength side was assigned to the overlap band of Ta and Tb. The reason for such a large spectral alternation for the axial substitution may be the increase in the orbital energy of HOMO-2, which has its electron density concentrated at the axial C-H bond. Regarding the effect of the hyperconjugation of C-C and C-H σ orbitals, the second perturbation energies of the interaction between Cα-Hax and Cβ-Hax were estimated for molecules by natural bond orbital (NBO) analysis. There is a correlation between the orbital energies of HOMO-2 and the changes in vicinal interaction by axial substitution.
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Affiliation(s)
- Yusuke Morisawa
- Department of Chemistry, School of Science and Engineering, Kindai University, Kowakae, Higashi-Osaka, Osaka 577-8502, Japan
| | - Yugo Higaki
- Department of Chemistry, School of Science and Engineering, Kindai University, Kowakae, Higashi-Osaka, Osaka 577-8502, Japan
| | - Yukihiro Ozaki
- School of Biological and Environmental Sciences, Kwansei Gakuin University, Sanda, Hyogo 669-1337, Japan.,Toyota Physical and Chemical Research Institute, Yokomichi, Nagakute, Aichi 480-1192, Japan
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29
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An Examination of Factors Influencing Small Proton Chemical Shift Differences in Nitrogen-Substituted Monodeuterated Methyl Groups. Symmetry (Basel) 2021. [DOI: 10.3390/sym13091610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Monodeuterated methyl groups have previously been demonstrated to provide access to long-lived nuclear spin states. This is possible when the CH2D rotamers have sufficiently different populations and the local environment is chiral, which foments a non-negligible isotropic chemical shift difference between the two CH2D protons. In this article, the focus is on the N-CH2D group of N-CH2D-2-methylpiperidine and other suitable CH2D-piperidine derivatives. We used a combined experimental and computational approach to investigate how rotameric symmetry breaking leads to a 1H CH2D chemical shift difference that can subsequently be tuned by a variety of factors such as temperature, acidity and 2-substituted molecular groups.
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30
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Naseri AM, Zarei M, Alizadeh S, Babaee S, Zolfigol MA, Nematollahi D, Arjomandi J, Shi H. Synthesis and application of [Zr-UiO-66-PDC-SO 3H]Cl MOFs to the preparation of dicyanomethylene pyridines via chemical and electrochemical methods. Sci Rep 2021; 11:16817. [PMID: 34413353 PMCID: PMC8377142 DOI: 10.1038/s41598-021-96001-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 08/03/2021] [Indexed: 02/07/2023] Open
Abstract
A metal-organic framework (MOF) with sulfonic acid tags as a novel mesoporous catalyst was synthesized. The precursor of Zr-UiO-66-PDC was synthesized both via chemical and electrochemical methods. Then, zirconium-based mesoporous metal-organic framework [Zr-UiO-66-PDC-SO3H]Cl was prepared by reaction of Zr-UiO-66-PDC and SO3HCl. The structure of [Zr-UiO-66-PDC-SO3H]Cl was confirmed by FT-IR, PXRD, FE-SEM, TEM, BET, EDX, and Mapping analysis. This mesoporous [Zr-UiO-66-PDC-SO3H]Cl was successfully applied for the synthesis of dicyanomethylene pyridine derivatives via condensation of various aldehyde, 2-aminoprop-1-ene-1,1,3-tricarbonitrile and malononitrile. At the electrochemical section, a green electrochemical method has successfully employed for rapid synthesis of the zirconium-based mesoporous metal-organic framework UiO-66-PDC at room temperature and atmospheric pressure. The synthesized UiO-66-PDC has a uniform cauliflower-like structure with a 13.5 nm mean pore diameter and 1081.6 m2 g-1 surface area. The described catalyst [Zr-UiO-66-PDC-SO3H]Cl was also employed for the convergent paired electrochemical synthesis of dihydropyridine derivatives as an environmentally friendly technique under constant current at 1.0 mA cm-2 in an undivided cell. The proposed method proceeds with moderate to good yields for the model via a cooperative vinylogous anomeric based oxidation.
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Affiliation(s)
| | - Mahmoud Zarei
- Faculty of Chemistry, Bu-Ali-Sina University, 65174-38683, Hamedan, Iran.
| | - Saber Alizadeh
- Faculty of Chemistry, Bu-Ali-Sina University, 65174-38683, Hamedan, Iran.
| | - Saeed Babaee
- Faculty of Chemistry, Bu-Ali-Sina University, 65174-38683, Hamedan, Iran
| | | | - Davood Nematollahi
- Faculty of Chemistry, Bu-Ali-Sina University, 65174-38683, Hamedan, Iran.
| | - Jalal Arjomandi
- Faculty of Chemistry, Bu-Ali-Sina University, 65174-38683, Hamedan, Iran
| | - Hu Shi
- School of Chemistry and Chemical Engineering, Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China
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31
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Torabi M, Zolfigol MA, Yarie M, Notash B, Azizian S, Azandaryani MM. Synthesis of triarylpyridines with sulfonate and sulfonamide moieties via a cooperative vinylogous anomeric-based oxidation. Sci Rep 2021; 11:16846. [PMID: 34413326 PMCID: PMC8377147 DOI: 10.1038/s41598-021-95830-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 07/21/2021] [Indexed: 02/07/2023] Open
Abstract
Herein, novel magnetic nanoparticles with pyridinium bridges namely Fe3O4@SiO2@PCLH-TFA through a multi-step pathway were designed and synthesized. The desired catalyst and its corresponding precursors were characterized with different techniques such as Fourier transform infrared (FT-IR) spectroscopy, 1H NMR, 13C NMR, Mass spectroscopy, energy dispersive X-ray (EDX) analysis, thermogravimetric/derivative thermogravimetry (TG/DTG) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM). In addition, the catalytic application of the prepared catalyst in the synthesis of new series of triarylpyridines bearing sulfonate and sulfonamide moieties via a cooperative vinylogous anomeric-based oxidation was highlighted. The current trend revealed that the mentioned catalyst shows high recoverability in the reported synthesis.
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Affiliation(s)
- Morteza Torabi
- Department of Organic Chemistry, Faculty of Chemistry, Bu-Ali Sina University, 6517838683, Hamedan, Iran
| | - Mohammad Ali Zolfigol
- Department of Organic Chemistry, Faculty of Chemistry, Bu-Ali Sina University, 6517838683, Hamedan, Iran.
| | - Meysam Yarie
- Department of Organic Chemistry, Faculty of Chemistry, Bu-Ali Sina University, 6517838683, Hamedan, Iran
| | - Behrouz Notash
- Department of Inorganic Chemistry and Catalysis, Shahid Beheshti University, Evin, Tehran, Iran
| | - Saeid Azizian
- Department of Physical Chemistry, Faculty of Chemistry, Bu-Ali Sina University, 6517838683, Hamedan, Iran
| | - Mina Mirzaei Azandaryani
- Department of Physical Chemistry, Faculty of Chemistry, Bu-Ali Sina University, 6517838683, Hamedan, Iran
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32
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Barzaga R, Lestón-Sánchez L, Aguilar-Galindo F, Estévez-Hernández O, Díaz-Tendero S. Synergy Effects in Heavy Metal Ion Chelation with Aryl- and Aroyl-Substituted Thiourea Derivatives. Inorg Chem 2021; 60:11984-12000. [PMID: 34308640 DOI: 10.1021/acs.inorgchem.1c01068] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Detection and removal of metal ion contaminants have attracted great interest due to the health risks that they represent for humans and wildlife. Among the proposed compounds developed for these purposes, thiourea derivatives have been shown as quite efficient chelating agents of metal cations and have been proposed for heavy metal ion removal and for components of high-selectivity sensors. Understanding the nature of metal-ionophore activity for these compounds is thus of high relevance. We present a theoretical study on the interaction between substituted thioureas and metal cations, namely, Cd2+, Hg2+, and Pb2+. Two substituent groups have been chosen: 2-furoyl and m-trifluoromethylphenyl. Combining density functional theory simulations with wave function analysis techniques, we study the nature of the metal-thiourea interaction and characterize the bonding properties. Here, it is shown how the N,N'-disubstituted derivative has a strong affinity for Hg2+, through cation-hydrogen interactions, due to its greater oxidizing capacity.
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Affiliation(s)
- Ransel Barzaga
- Instituto de Ciencia y Tecnología de Materiales, Universidad de La Habana, 10400 La Habana, Cuba.,Departmento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Lucia Lestón-Sánchez
- Departmento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Fernando Aguilar-Galindo
- Departmento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain.,Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, Donostia-San Sebastián, E-20018, Spain
| | | | - Sergio Díaz-Tendero
- Departmento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain.,Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid, Spain.,Institute for Advanced Research in Chemical Science (IAdChem), Universidad Autónoma de Madrid, 28049 Madrid, Spain
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33
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Mundlapati VR, Imani Z, Goldsztejn G, Gloaguen E, Brenner V, Le Barbu-Debus K, Zehnacker-Rentien A, Baltaze JP, Robin S, Mons M, Aitken DJ. A theoretical and experimental case study of the hydrogen bonding predilection of S-methylcysteine. Amino Acids 2021; 53:621-633. [PMID: 33743071 DOI: 10.1007/s00726-021-02967-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/12/2021] [Indexed: 12/17/2022]
Abstract
S-containing amino acids can lead to two types of local NH···S interactions which bridge backbone NH sites to the side chain to form either intra- or inter-residue H-bonds. The present work reports on the conformational preferences of S-methyl-L-cysteine, Cys(Me), using a variety of investigating tools, ranging from quantum chemistry simulations, gas-phase UV and IR laser spectroscopy, and solution state IR and NMR spectroscopies, on model compounds comprising one or two Cys(Me) residues. We demonstrate that in gas phase and in low polarity solution, the C- and N-capped model compound for one Cys(Me) residue adopts a preferred C5-C6γ conformation which combines an intra-residue N-H···O=C backbone interaction (C5) and an inter-residue N-H···S interaction implicating the side-chain sulfur atom (C6γ). In contrast, the dominant conformation of the C- and N-capped model compound featuring two consecutive Cys(Me) residues is a regular type I β-turn. This structure is incompatible with concomitant C6γ interactions, which are no longer in evidence. Instead, C5γ interactions occur, that are fully consistent with the turn geometry and additionally stabilize the structure. Comparison with the thietane amino acid Attc, which exhibits a rigid cyclic side chain, pinpoints the significance of side chain flexibility for the specific conformational behavior of Cys(Me).
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Affiliation(s)
- Venkateswara Rao Mundlapati
- Laboratoire Interactions, Dynamiques Et Lasers (LIDYL), CEA, CNRS, Université Paris-Saclay, 91191, Gif-sur-Yvette, France
- Institut de Recherche en Astrophysique Et Planétologie (IRAP), Université de Toulouse (UPS), CNRS, CNES, 9 Avenue du Colonel Roche, 31028, Toulouse, France
| | - Zeynab Imani
- Institut de Chimie Moléculaire Et Des Matériaux D'Orsay (ICMMO), Université Paris-Saclay, CNRS, 91405, Orsay, France
| | - Gildas Goldsztejn
- Laboratoire Interactions, Dynamiques Et Lasers (LIDYL), CEA, CNRS, Université Paris-Saclay, 91191, Gif-sur-Yvette, France
- Institut Des Sciences Moléculaires D'Orsay (ISMO), Université Paris-Saclay, CNRS, 91405, Orsay, France
| | - Eric Gloaguen
- Laboratoire Interactions, Dynamiques Et Lasers (LIDYL), CEA, CNRS, Université Paris-Saclay, 91191, Gif-sur-Yvette, France
| | - Valérie Brenner
- Laboratoire Interactions, Dynamiques Et Lasers (LIDYL), CEA, CNRS, Université Paris-Saclay, 91191, Gif-sur-Yvette, France
| | - Katia Le Barbu-Debus
- Institut Des Sciences Moléculaires D'Orsay (ISMO), Université Paris-Saclay, CNRS, 91405, Orsay, France
| | - Anne Zehnacker-Rentien
- Institut Des Sciences Moléculaires D'Orsay (ISMO), Université Paris-Saclay, CNRS, 91405, Orsay, France
| | - Jean-Pierre Baltaze
- Institut de Chimie Moléculaire Et Des Matériaux D'Orsay (ICMMO), Université Paris-Saclay, CNRS, 91405, Orsay, France
| | - Sylvie Robin
- Institut de Chimie Moléculaire Et Des Matériaux D'Orsay (ICMMO), Université Paris-Saclay, CNRS, 91405, Orsay, France
- Faculté de Pharmacie, Université de Paris, 75006, Paris, France
| | - Michel Mons
- Laboratoire Interactions, Dynamiques Et Lasers (LIDYL), CEA, CNRS, Université Paris-Saclay, 91191, Gif-sur-Yvette, France.
| | - David J Aitken
- Institut de Chimie Moléculaire Et Des Matériaux D'Orsay (ICMMO), Université Paris-Saclay, CNRS, 91405, Orsay, France.
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Brydon SC, Harris BL, White JM. Computational Study of the Donor-Acceptor Interactions Underlying the Variable Oxygen Probe. J Org Chem 2021; 86:3960-3969. [PMID: 33590758 DOI: 10.1021/acs.joc.0c02811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The variable oxygen probe (VOP) is a crystallographic technique that has been used to explore the relative donor abilities of various filled orbitals ranging from vicinal lone pairs to polarized heteroatom-carbon bonds, remote π functionalities, and strained carbon-carbon (CC) bonds. In this study, the donor-acceptor interactions which underlie the VOP have been explored in the gas phase using density functional theory on the model systems 1-13 with natural bond orbital analysis of the various donor-acceptor interactions involving both neutral and charged σ* antibonding orbitals as the acceptor probes. Updated values for the VOP slopes of 1-13 were shown to relate qualitatively with the sum of all significant donor-acceptor interactions present in these derivatives. Application of the VOP to calculated structures of 1-13 with various -OR substituents revealed a similar relationship between the C-OR bond distance to pKa (ROH). However, the VOP slopes in the gas phase were significantly smaller in magnitude than those obtained from crystal structural data, likely due to the valence form (C+-OR) being disfavored in the former, highlighting the advantage of the VOP as an experimental technique to discriminate donor ability more effectively than calculated structures.
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Affiliation(s)
- Samuel C Brydon
- School of Chemistry and Bio21 Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Benjamin L Harris
- School of Chemistry and Bio21 Institute, University of Melbourne, Parkville, VIC 3010, Australia
| | - Jonathan M White
- School of Chemistry and Bio21 Institute, University of Melbourne, Parkville, VIC 3010, Australia
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35
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Oliver L, Ragam S, Deslongchamps P, White JM, Hancock A, Brydon S. Application of the Variable Oxygen Probe to Derivatives of 2,6-Dimethyltetrahydropyran-4-ol: Evidence for Through-Bond nO–σCC–σ*CO Interactions. Aust J Chem 2021. [DOI: 10.1071/ch20149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The variable oxygen probe has been applied to axial and equatorial 4-pyranols 4 and 5 and their ester and ether derivatives. Plots of C–OR bond distance versus pKa (ROH) provided evidence for slightly stronger donation into the σ*C–OR antibonding orbital in the equatorial derivatives 5 than in the axial derivatives 4, which is consistent with the presence of a through-bond nO–σCC–σ*CO interaction in 5. Evidence in support of this interpretation was also provided by density functional theory (DFT) calculations and natural bond orbital (NBO) analyses of the various orbital interactions in the 4-pyranols 4 and 5, their protonated analogues 4·H2O+ and 5·H2O+, and the corresponding cyclohexane derivatives 6, 7, 6·H2O+, and 7·H2O+.
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36
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Zhao Y, Zeng J, Zhu J. Tuning the hyperconjugative aromaticity in Au(III)-substituted indoliums. Dalton Trans 2021; 50:8096-8101. [PMID: 34018516 DOI: 10.1039/d1dt00599e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
As a fundamental concept in chemistry, aromaticity has been extended from traditional organics to organometallics. Similarly, hyperconjugative aromaticity (HCA) has also been developed from main group to transition metal systems through the hyperconjugation of the substituents. However, it remains unclear that how the oxidation state of transition metal in the substituents affects the HCA. Herein, we demonstrate via density functional theory calculations that HCA could disappear in indoliums when the Au(i) substituents are changed to the Au(iii) ones. By tuning the ligand or cis-trans isomerization, HCA could be regained or enhanced in indoliums containing Au(iii) substitutents.
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Affiliation(s)
- Yu Zhao
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
| | - Jie Zeng
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
| | - Jun Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
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37
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Xu LP, Roque JB, Sarpong R, Musaev DG. Reactivity and Selectivity Controlling Factors in the Pd/Dialkylbiarylphosphine-Catalyzed C–C Cleavage/Cross-Coupling of an N-Fused Bicyclo α-Hydroxy-β-Lactam. J Am Chem Soc 2020; 142:21140-21152. [DOI: 10.1021/jacs.0c10220] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Li-Ping Xu
- Cherry L. Emerson Center for Scientific Computation, and Department of Chemistry, Emory University, 1521 Dickey Drive, Atlanta, Georgia 30322, United States
- School of Chemistry and Chemical Engineering, Shandong University of Technology, Zibo 255000, China
| | - Jose B. Roque
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Richmond Sarpong
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Djamaladdin G. Musaev
- Cherry L. Emerson Center for Scientific Computation, and Department of Chemistry, Emory University, 1521 Dickey Drive, Atlanta, Georgia 30322, United States
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38
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Petrov PA, Kadilenko EM, Sukhikh TS, Eltsov IV, Gushchin AL, Nadolinny VA, Sokolov MN, Gritsan NP. A Sterically Hindered Derivative of 2,1,3-Benzotelluradiazole: A Way to the First Structurally Characterised Monomeric Tellurium-Nitrogen Radical Anion. Chemistry 2020; 26:14688-14699. [PMID: 32776633 DOI: 10.1002/chem.202002799] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/22/2020] [Indexed: 12/14/2022]
Abstract
Interaction of the tetradentate redox-active 6,6'-[1,2-phenylenebis(azanediyl)]bis(2,4-di-tert-butylphenol) (H4 L) with TeCl4 leads to neutral diamagnetic compound TeL (1) in high yield. The molecule of 1 has a nearly planar TeN2 O2 fragment, which suggests the formulation of 1 as TeII L2- , in agreement with the results of DFT calculations and QTAIM and NBO analyses. Reduction of 1 with one equivalent of [CoCp2 ] leads to quantitative formation of the paramagnetic salt [CoCp2 ]+ [1].- , which was characterised by single-crystal XRD. The solution EPR spectrum of [CoCp2 ]+ [1].- at room temperature features a quintet due to splitting on two equivalent 14 N nuclei. Below 150 K it turns into a broad singlet line with two weak satellites due to the splitting on the 125 Te nucleus. Two-component relativistic DFT calculations perfectly reproduce the a(14 N) HFI constants and A∥ (125 Te) value responsible for the low-temperature satellite splitting. Calculations predict that the additional electron in 1.- is localised mainly on L, while the spin density is delocalised over the whole molecule with significant localisation on the Te atom (≥30 %). All these data suggest that 1.- can be regarded as the first example of a structurally characterised monomeric tellurium-nitrogen radical anion.
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Affiliation(s)
- Pavel A Petrov
- Nikolaev Institute of Inorganic Chemistry SB RAS, Lavrentiev Av. 3, 630090, Novosibirsk, Russia
| | - Evgeny M Kadilenko
- Novosibirsk State University, Pirogova St. 2, 630090, Novosibirsk, Russia.,Voevodsky Institute of Chemical Kinetics and Combustion SB RAS, Institutskaya St. 3, 630090, Novosibirsk, Russia
| | - Taisiya S Sukhikh
- Nikolaev Institute of Inorganic Chemistry SB RAS, Lavrentiev Av. 3, 630090, Novosibirsk, Russia
| | - Ilia V Eltsov
- Novosibirsk State University, Pirogova St. 2, 630090, Novosibirsk, Russia
| | - Artem L Gushchin
- Nikolaev Institute of Inorganic Chemistry SB RAS, Lavrentiev Av. 3, 630090, Novosibirsk, Russia
| | - Vladimir A Nadolinny
- Nikolaev Institute of Inorganic Chemistry SB RAS, Lavrentiev Av. 3, 630090, Novosibirsk, Russia
| | - Maxim N Sokolov
- Nikolaev Institute of Inorganic Chemistry SB RAS, Lavrentiev Av. 3, 630090, Novosibirsk, Russia
| | - Nina P Gritsan
- Novosibirsk State University, Pirogova St. 2, 630090, Novosibirsk, Russia.,Voevodsky Institute of Chemical Kinetics and Combustion SB RAS, Institutskaya St. 3, 630090, Novosibirsk, Russia
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39
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Gloaguen E, Mons M, Schwing K, Gerhards M. Neutral Peptides in the Gas Phase: Conformation and Aggregation Issues. Chem Rev 2020; 120:12490-12562. [PMID: 33152238 DOI: 10.1021/acs.chemrev.0c00168] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Combined IR and UV laser spectroscopic techniques in molecular beams merged with theoretical approaches have proven to be an ideal tool to elucidate intrinsic structural properties on a molecular level. It offers the possibility to analyze structural changes, in a controlled molecular environment, when successively adding aggregation partners. By this, it further makes these techniques a valuable starting point for a bottom-up approach in understanding the forces shaping larger molecular systems. This bottom-up approach was successfully applied to neutral amino acids starting around the 1990s. Ever since, experimental and theoretical methods developed further, and investigations could be extended to larger peptide systems. Against this background, the review gives an introduction to secondary structures and experimental methods as well as a summary on theoretical approaches. Vibrational frequencies being characteristic probes of molecular structure and interactions are especially addressed. Archetypal biologically relevant secondary structures investigated by molecular beam spectroscopy are described, and the influences of specific peptide residues on conformational preferences as well as the competition between secondary structures are discussed. Important influences like microsolvation or aggregation behavior are presented. Beyond the linear α-peptides, the main results of structural analysis on cyclic systems as well as on β- and γ-peptides are summarized. Overall, this contribution addresses current aspects of molecular beam spectroscopy on peptides and related species and provides molecular level insights into manifold issues of chemical and biochemical relevance.
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Affiliation(s)
- Eric Gloaguen
- CEA, CNRS, Université Paris-Saclay, CEA Paris-Saclay, Bât 522, 91191 Gif-sur-Yvette, France
| | - Michel Mons
- CEA, CNRS, Université Paris-Saclay, CEA Paris-Saclay, Bât 522, 91191 Gif-sur-Yvette, France
| | - Kirsten Schwing
- TU Kaiserslautern & Research Center Optimas, Erwin-Schrödinger-Straße 52, D-67663 Kaiserslautern, Germany
| | - Markus Gerhards
- TU Kaiserslautern & Research Center Optimas, Erwin-Schrödinger-Straße 52, D-67663 Kaiserslautern, Germany
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40
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de Melo UZ, Fernandes CDS, Francisco CB, Carini TC, Gauze GDF, Rittner R, Basso EA. Conformational Isomerism of 3-Chalcogenomethyl- N-Methyl-2-Pyrrolidinones: Insights from NMR Spectroscopy and Molecular Modeling. J Phys Chem A 2020; 124:8509-8518. [PMID: 32960599 DOI: 10.1021/acs.jpca.0c06679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A conformational analysis of N-methyl-2-pyrrolidinone 3-substituted by methoxyl, thiomethoxyl, and selenomethoxyl is reported by means of 1H nuclear magnetic resonance spectroscopy and electronic structure calculations. The five-membered ring has an envelope conformation with the α-carbonyl substituent being able to assume two positions: pseudo-axial and pseudo-equatorial. In vacuum, the calculations pointed to the pseudo-axial conformer as the most stable one, and this preference increases with the size of the substituent and a decrease in its electronegativity. Natural bond orbital analysis evidenced the importance of electron delocalization on the stability, and a principal component of analysis (PCA) plot of the hyperconjugative interactions revealed the main ones. Steric and electrostatic effects were also investigated by energy decomposition analysis.
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Affiliation(s)
- Ulisses Zonta de Melo
- Departamento de Quı́mica, Universidade Estadual de Maringá, Maringá 87020-900, Brazil
| | | | | | - Tânia Cristina Carini
- Departamento de Quı́mica, Universidade Estadual de Maringá, Maringá 87020-900, Brazil
| | | | - Roberto Rittner
- Instituto de Quı́mica, Universidade Estadual de Campinas, Campinas 13083-970, Brazil
| | - Ernani Abicht Basso
- Departamento de Quı́mica, Universidade Estadual de Maringá, Maringá 87020-900, Brazil
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41
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Nees S, Kupfer T, Hofmann A, Braunschweig H. Planar Cyclopenten-4-yl Cations: Highly Delocalized π Aromatics Stabilized by Hyperconjugation. Angew Chem Int Ed Engl 2020; 59:18809-18815. [PMID: 32701182 PMCID: PMC7589364 DOI: 10.1002/anie.202009644] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Indexed: 11/25/2022]
Abstract
Theoretical studies predicted the planar cyclopenten-4-yl cation to be a classical carbocation, and the highest-energy isomer of C5 H7 + . Hence, its existence has not been verified experimentally so far. We were now able to isolate two stable derivatives of the cyclopenten-4-yl cation by reaction of bulky alanes CpR AlBr2 with AlBr3 . Elucidation of their (electronic) structures by X-ray diffraction and quantum chemistry studies revealed planar geometries and strong hyperconjugation interactions primarily from the C-Al σ bonds to the empty p orbital of the cationic sp2 carbon center. A close inspection of the molecular orbitals (MOs) and of the anisotropy of current (induced) density (ACID), as well as the evaluation of various aromaticity descriptors indicated distinct aromaticity for these cyclopenten-4-yl derivatives, which strongly contrasts the classical description of this system. Here, strong delocalization of π electrons spanning the whole carbocycle has been verified, thus providing rare examples of π aromaticity involving saturated sp3 carbon atoms.
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Affiliation(s)
- Samuel Nees
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Thomas Kupfer
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Alexander Hofmann
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Holger Braunschweig
- Institut für Anorganische ChemieJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
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42
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Nees S, Kupfer T, Hofmann A, Braunschweig H. Stabilisierung planarer Cyclopenten‐4‐yl‐Kationen durch Hyperkonjugation und π‐Delokalisierung. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202009644] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Samuel Nees
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Thomas Kupfer
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Alexander Hofmann
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
| | - Holger Braunschweig
- Institut für Anorganische Chemie Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
- Institut für Nachhaltige Chemie & Katalyse mit Bor Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Deutschland
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43
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Garner MH, Corminboeuf C. Correlation between Optical Activity and the Helical Molecular Orbitals of Allene and Cumulenes. Org Lett 2020; 22:8028-8033. [DOI: 10.1021/acs.orglett.0c02980] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Marc H. Garner
- Laboratory for Computational Molecular Design, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Clemence Corminboeuf
- Laboratory for Computational Molecular Design, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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44
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Torabi M, Yarie M, Karimi F, Zolfigol MA. Catalytic synthesis of coumarin-linked nicotinonitrile derivatives via a cooperative vinylogous anomeric-based oxidation. RESEARCH ON CHEMICAL INTERMEDIATES 2020. [DOI: 10.1007/s11164-020-04267-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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45
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Junor GP, Lorkowski J, Weinstein CM, Jazzar R, Pietraszuk C, Bertrand G. The Influence of C(sp
3
)H–Selenium Interactions on the
77
Se NMR Quantification of the π‐Accepting Properties of Carbenes. Angew Chem Int Ed Engl 2020; 59:22028-22033. [DOI: 10.1002/anie.202010744] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Indexed: 01/06/2023]
Affiliation(s)
- Glen P. Junor
- UCSD-CNRS Joint Research Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California, San Diego La Jolla CA 92093-0358 USA
| | - Jan Lorkowski
- UCSD-CNRS Joint Research Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California, San Diego La Jolla CA 92093-0358 USA
- Faculty of Chemistry Department of Organometallic Chemistry Adam Mickiewicz University in Poznań ul, Uniwersytetu Poznanskiego 8 61-614 Poznań Poland
| | - Cory M. Weinstein
- UCSD-CNRS Joint Research Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California, San Diego La Jolla CA 92093-0358 USA
| | - Rodolphe Jazzar
- UCSD-CNRS Joint Research Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California, San Diego La Jolla CA 92093-0358 USA
| | - Cezary Pietraszuk
- Faculty of Chemistry Department of Organometallic Chemistry Adam Mickiewicz University in Poznań ul, Uniwersytetu Poznanskiego 8 61-614 Poznań Poland
| | - Guy Bertrand
- UCSD-CNRS Joint Research Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California, San Diego La Jolla CA 92093-0358 USA
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46
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Junor GP, Lorkowski J, Weinstein CM, Jazzar R, Pietraszuk C, Bertrand G. The Influence of C(sp
3
)H–Selenium Interactions on the
77
Se NMR Quantification of the π‐Accepting Properties of Carbenes. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202010744] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Glen P. Junor
- UCSD-CNRS Joint Research Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California, San Diego La Jolla CA 92093-0358 USA
| | - Jan Lorkowski
- UCSD-CNRS Joint Research Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California, San Diego La Jolla CA 92093-0358 USA
- Faculty of Chemistry Department of Organometallic Chemistry Adam Mickiewicz University in Poznań ul, Uniwersytetu Poznanskiego 8 61-614 Poznań Poland
| | - Cory M. Weinstein
- UCSD-CNRS Joint Research Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California, San Diego La Jolla CA 92093-0358 USA
| | - Rodolphe Jazzar
- UCSD-CNRS Joint Research Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California, San Diego La Jolla CA 92093-0358 USA
| | - Cezary Pietraszuk
- Faculty of Chemistry Department of Organometallic Chemistry Adam Mickiewicz University in Poznań ul, Uniwersytetu Poznanskiego 8 61-614 Poznań Poland
| | - Guy Bertrand
- UCSD-CNRS Joint Research Laboratory (UMI 3555) Department of Chemistry and Biochemistry University of California, San Diego La Jolla CA 92093-0358 USA
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47
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Mills LR, Monteith JJ, Dos Passos Gomes G, Aspuru-Guzik A, Rousseaux SAL. The Cyclopropane Ring as a Reporter of Radical Leaving-Group Reactivity for Ni-Catalyzed C(sp 3)-O Arylation. J Am Chem Soc 2020; 142:13246-13254. [PMID: 32609494 DOI: 10.1021/jacs.0c06904] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The ability to understand and predict reactivity is essential for the development of new reactions. In the context of Ni-catalyzed C(sp3)-O functionalization, we have developed a unique strategy employing activated cyclopropanols to aid the design and optimization of a redox-active leaving group for C(sp3)-O arylation. In this chemistry, the cyclopropane ring acts as a reporter of leaving-group reactivity, since the ring-opened product is obtained under polar (2e) conditions, and the ring-closed product is obtained under radical (1e) conditions. Mechanistic studies demonstrate that the optimal leaving group is redox-active and are consistent with a Ni(I)/Ni(III) catalytic cycle. The optimized reaction conditions are also used to synthesize a number of arylcyclopropanes, which are valuable pharmaceutical motifs.
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Affiliation(s)
- L Reginald Mills
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - John J Monteith
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Gabriel Dos Passos Gomes
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.,Department of Computer Science, University of Toronto, 214 College St., Toronto, Ontario M5T 3A1, Canada
| | - Alán Aspuru-Guzik
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.,Department of Computer Science, University of Toronto, 214 College St., Toronto, Ontario M5T 3A1, Canada.,Vector Institute for Artificial Intelligence, 661 University Ave. Suite 710, Toronto, Ontario M5G 1M1, Canada.,Lebovic Fellow, Canadian Institute for Advanced Research (CIFAR), 661 University Ave, Toronto, Ontario M5G 1M1, Canada
| | - Sophie A L Rousseaux
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
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48
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Babaee S, Zarei M, Sepehrmansourie H, Zolfigol MA, Rostamnia S. Synthesis of Metal-Organic Frameworks MIL-101(Cr)-NH 2 Containing Phosphorous Acid Functional Groups: Application for the Synthesis of N-Amino-2-pyridone and Pyrano [2,3- c]pyrazole Derivatives via a Cooperative Vinylogous Anomeric-Based Oxidation. ACS OMEGA 2020; 5:6240-6249. [PMID: 32258858 PMCID: PMC7114146 DOI: 10.1021/acsomega.9b02133] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 03/05/2020] [Indexed: 05/24/2023]
Abstract
In the current paper, we successfully developed and used metal-organic frameworks (MOFs) based on MIL-101(Cr)-NH2 with phosphorus acid functional groups MIL-101(Cr)-N(CH2PO3H2)2. The synthesized metal-organic frameworks (MOFs) as a multi-functional heterogeneous and nanoporous catalyst were used for the synthesis of N-amino-2-pyridone and pyrano [2,3-c]pyrazole derivatives via reaction of ethyl cyanoacetate or ethyl acetoacetate, hydrazine hydrate, malononitrile, and various aldehydes. The final step of the reaction mechanism was preceded by a cooperative vinylogous anomeric-based oxidation. Recycle and reusability of the described catalyst MIL-101(Cr)-N(CH2PO3H2)2 were also investigated.
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Affiliation(s)
- Saeed Babaee
- Department
of Organic Chemistry, Faculty of Chemistry, Bu-Ali Sina University, P.O. Box 6517838683, Hamedan, Iran
| | - Mahmoud Zarei
- Department
of Organic Chemistry, Faculty of Chemistry, Bu-Ali Sina University, P.O. Box 6517838683, Hamedan, Iran
| | - Hassan Sepehrmansourie
- Department
of Organic Chemistry, Faculty of Chemistry, Bu-Ali Sina University, P.O. Box 6517838683, Hamedan, Iran
| | - Mohammad Ali Zolfigol
- Department
of Organic Chemistry, Faculty of Chemistry, Bu-Ali Sina University, P.O. Box 6517838683, Hamedan, Iran
| | - Sadegh Rostamnia
- Organic
and Nano Group (ONG), Department of Chemistry, Faculty of Science, University of Maragheh, P.O. Box 55181-83111, Maragheh, Iran
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49
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Harris T, Chenoweth DM. Sterics and Stereoelectronics in Aza-Glycine: Impact of Aza-Glycine Preorganization in Triple Helical Collagen. J Am Chem Soc 2019; 141:18021-18029. [DOI: 10.1021/jacs.9b05524] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Trevor Harris
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| | - David M. Chenoweth
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
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50
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Levandowski BJ, Raines RT, Houk KN. Hyperconjugative π → σ* CF Interactions Stabilize the Enol Form of Perfluorinated Cyclic Keto-Enol Systems. J Org Chem 2019; 84:6432-6436. [PMID: 30990687 DOI: 10.1021/acs.joc.9b00825] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Lindner and Lemal showed that perfluorination of keto-enol systems significantly shifts the equilibrium toward the enol tautomer. Quantum mechanical calculations now reveal that the shift in equilibrium is the result of the stabilization of the enol tautomer by hyperconjugative π → σ*CF interactions and the destabilization of the keto tautomer by the electron withdrawal induced by the neighboring fluorine atoms. The preference for the enol tautomer further increases in smaller perfluorinated cyclic keto-enol systems. This trend is in contrast to the nonfluorinated compounds, where the enol is strongly disfavored in the smaller rings. The fluoro effect overrides the effect of the ring size that controls the equilibria in nonfluorinated compounds. The increased overlap of the enol π bond with the σ*CF orbitals of the allylic C-F bonds results in the increased preference for the enol tautomer in smaller perfluorinated keto-enol systems. We show here why the effect is much greater than in 3,3-difluorocyclooctyne.
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Affiliation(s)
- Brian J Levandowski
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States.,Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Ronald T Raines
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - K N Houk
- Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
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