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Jia L, Liu R, Lv J, Liu L, Zhang Z, Wang Y, Hou X. Probing the interactions of GlcNH 2 with boric acid via NMR spectroscopy. Phys Chem Chem Phys 2021; 23:15758-15765. [PMID: 34286766 DOI: 10.1039/d1cp01795k] [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
The essential role of boronic esters in controlling both the direction and selectivity of chemical reactions as well as their significant function in catalytic activity have been demonstrated for industrially important processes. The specific interaction analyses of the monosaccharide GlcNH2 with boric acid are of interest since monosaccharides serve as model systems for the more sophisticated carbohydrate molecules. The interaction of GlcNH2 with boric acid was systematically investigated by numerous NMR techniques. A 1 : 1 chelate boron complex coordinated at the cis-1,2 position of GlcNH2 was identified as the major species in DMSO-d6 solution via1H and 13C INEPT DOSY NMR spectroscopy. This specific boron nitrogen coordination mechanism was further supported by the 1H-15N HSQC spectra. Variations in the spin-lattice relaxation times (T1) of the 13C1 nucleus also provided quantitative data regarding this non-covalent interactions. This is an application of 1H, 13C INEPT DOSY, 1H-15N HSQC, and relaxation methods to study such aggregations in solutions. These methods have potential applications in the characterization of reactive intermediates in biomass conversions.
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Affiliation(s)
- Lingyu Jia
- Engineering Research Center of Advanced Functional Material Manufacturing of Ministry of Education, School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, People's Republic of China. and Shanxi Engineering Research Center of Biorefinery, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, People's Republic of China. and School of Medical Sciences, Zhengzhou University, Zhengzhou 450001, People's Republic of China
| | - Rui Liu
- Engineering Research Center of Advanced Functional Material Manufacturing of Ministry of Education, School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, People's Republic of China.
| | - Jiayu Lv
- Engineering Research Center of Advanced Functional Material Manufacturing of Ministry of Education, School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, People's Republic of China.
| | - Luqi Liu
- Engineering Research Center of Advanced Functional Material Manufacturing of Ministry of Education, School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, People's Republic of China.
| | - Zhenzhou Zhang
- Engineering Research Center of Advanced Functional Material Manufacturing of Ministry of Education, School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, People's Republic of China.
| | - Yingxiong Wang
- Shanxi Engineering Research Center of Biorefinery, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, People's Republic of China.
| | - Xianglin Hou
- Shanxi Engineering Research Center of Biorefinery, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, People's Republic of China.
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Evans R. The interpretation of small molecule diffusion coefficients: Quantitative use of diffusion-ordered NMR spectroscopy. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2020; 117:33-69. [PMID: 32471534 DOI: 10.1016/j.pnmrs.2019.11.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 11/20/2019] [Accepted: 11/20/2019] [Indexed: 06/11/2023]
Abstract
Measuring accurate molecular self-diffusion coefficients, D, by nuclear magnetic resonance (NMR) techniques has become routine as hardware, software and experimental methodologies have all improved. However, the quantitative interpretation of such data remains difficult, particularly for small molecules. This review article first provides a description of, and explanation for, the failure of the Stokes-Einstein equation to accurately predict small molecule diffusion coefficients, before moving on to three broadly complementary methods for their quantitative interpretation. Two are based on power laws, but differ in the nature of the reference molecules used. The third addresses the uncertainties in the Stokes-Einstein equation directly. For all three methods, a wide range of examples are used to show the range of chemistry to which diffusion NMR can be applied, and how best to implement the different methods to obtain quantitative information from the chemical systems studied.
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Affiliation(s)
- Robert Evans
- Aston Institute of Materials Research, School of Engineering and Applied Science, Aston University, Birmingham B4 7ET, United Kingdom.
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3
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Knauer L, Strohmann C. The structure-defining incorporation of chloride in methyllithium dimers. Chem Commun (Camb) 2020; 56:13543-13546. [DOI: 10.1039/d0cc05547f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Two polymeric solid-state structures of pmdta-stabilized methyllithium with co-existing tetrameric and dimeric units were obtained, linked by the structure-giving “contaminant” LiCl, incorporated only in dimeric entities.
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Affiliation(s)
- Lena Knauer
- Institute for Inorganic Chemistry
- TU Dortmund University
- 44227 Dortmund
- Germany
| | - Carsten Strohmann
- Institute for Inorganic Chemistry
- TU Dortmund University
- 44227 Dortmund
- Germany
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4
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Zaccaria F, Zuccaccia C, Cipullo R, Macchioni A. Extraction of Reliable Molecular Information from Diffusion NMR Spectroscopy: Hydrodynamic Volume or Molecular Mass? Chemistry 2019; 25:9930-9937. [PMID: 30998838 DOI: 10.1002/chem.201900812] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Indexed: 01/31/2023]
Abstract
Measuring accurate translational self-diffusion coefficients (Dt ) by NMR techniques with modern spectrometers has become rather routine. In contrast, the derivation of reliable molecular information therefrom still remains a nontrivial task. In this paper, two established approaches to estimating molecular size in terms of hydrodynamic volume (VH ) or molecular weight (M) are compared. Ad hoc designed experiments allowed the critical aspects of their application to be explored by translating relatively complex theoretical principles into practical take-home messages. For instance, comparing the Dt values of three isosteric Cp2 MCl2 complexes (Cp=cyclopentadienyl, M=Ti, Zr, Hf), having significantly different molecular mass, provided an empirical demonstration that VH is the critical molecular property affecting Dt . This central concept served to clarify the assumptions behind the derivation of Dt =ƒ(M) power laws from the Stokes-Einstein equation. Some pitfalls in establishing log (Dt ) versus log (M) linear correlations for a set of species have been highlighted by further investigations of selected examples. The effectiveness of the Stokes-Einstein equation itself in describing the aggregation or polymerization of differently shaped species has been explored by comparing, for example, a ball-shaped silsesquioxane cage with its cigar-like dimeric form, or styrene with polystyrene macromolecules.
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Affiliation(s)
- Francesco Zaccaria
- Dipartimento di Chimica, Biologia e Biotecnologie and CIRCC, Università di Perugia, Via Elce di Sotto 8, 06123, Perugia, Italy
| | - Cristiano Zuccaccia
- Dipartimento di Chimica, Biologia e Biotecnologie and CIRCC, Università di Perugia, Via Elce di Sotto 8, 06123, Perugia, Italy
| | - Roberta Cipullo
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Via Cintia, 80126, Napoli, Italy
| | - Alceo Macchioni
- Dipartimento di Chimica, Biologia e Biotecnologie and CIRCC, Università di Perugia, Via Elce di Sotto 8, 06123, Perugia, Italy
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Abstract
The solution structures, stabilities, physical properties, and reactivities of sodium diisopropylamide (NaDA) in a variety of coordinating solvents are described. NaDA is stable for months as a solid or as a 1.0 M solution in N,N-dimethylethylamine (DMEA) at -20 °C. A combination of NMR spectroscopic and computational studies show that NaDA is a disolvated symmetric dimer in DMEA, N,N-dimethyl-n-butylamine, and N-methylpyrrolidine. Tetrahydrofuran (THF) readily displaces DMEA, affording a tetrasolvated cyclic dimer at all THF concentrations. Dimethoxyethane (DME) and N,N,N',N'-tetramethylethylenediamine quantitatively displace DMEA, affording doubly chelated symmetric dimers. The trifunctional ligands N,N,N',N″,N″-pentamethyldiethylenetriamine and diglyme bind the dimer as bidentate rather than tridentate ligands. Relative rates of solvent decompositions are reported, and rate studies for the decomposition of THF and DME are consistent with monomer-based mechanisms.
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Affiliation(s)
- Russell F. Algera
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853–1301, United States,
| | - Yun Ma
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853–1301, United States,
| | - David B. Collum
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853–1301, United States,
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Guang J, Liu Q, Hopson R, Kagan G, Li W, Monroe TB, Williard PG. Conformational Polymorphism of Lithium Pinacolone Enolate. J Am Chem Soc 2016; 138:15177-15188. [PMID: 27762552 DOI: 10.1021/jacs.6b08177] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A metastable, polymorphic hexameric crystal structure of lithium pinacolone enolate (LiOPin) is reported along with three preparation methods. NMR-based structural characterization implies that the lithium pinacolate hexamer deaggregates to a tetramer in toluene but retains mainly the hexameric structure in nonaromatic hydrocarbon solvents such as cyclohexane. Moreover, the presence of a small amount of lithium aldolate (LiOA) dramatically influences the aggregation state of LiOPin by forming a mixed aggregate with a 3:1 ratio (LiOPin3·LiOA).
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Affiliation(s)
- Jie Guang
- Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States
| | - Qiyong Liu
- Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States
| | - Russell Hopson
- Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States
| | - Gerald Kagan
- Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States
| | - Weibin Li
- Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States
| | - Thomas B Monroe
- Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States
| | - Paul G Williard
- Department of Chemistry, Brown University , Providence, Rhode Island 02912, United States
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Bénéteau R, Boussonnière A, Rouaud JC, Lebreton J, Graton J, Jacquemin D, Sebban M, Oulyadi H, Hamdoun G, Hancock AN, Schiesser CH, Dénès F. Radical Cyclisation of α-Halo Aluminium Acetals: A Mechanistic Study. Chemistry 2016; 22:4809-24. [PMID: 26890896 DOI: 10.1002/chem.201504780] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Indexed: 11/06/2022]
Abstract
α-Bromo aluminium acetals are suitable substrates for Ueno-Stork-like radical cyclisations affording γ-lactols and acid-sensitive methylene-γ-lactols in high yields. The mechanistic study herein sets the scope and limitation of this reaction. The influence of the halide (or chalcogenide) atom X (X=Cl, Br, I, SPh, SePh) in the precursors α-haloesters, as well as influence of the solvent and temperature was studied. The structure of the aluminium acetal intermediates resulting from the reduction of the corresponding α-haloesters has been investigated by low-temperature (13) C-INEPT diffusion-ordered NMR spectroscopy (DOSY) experiments and quantum calculations, providing new insights into the structures of these thermally labile intermediates. Oxygen-bridged dimeric structures with a planar Al2 O2 ring are proposed for the least hindered aluminium acetals, while monomeric structures seem to prevail for the most hindered species. A comparison against the radical cyclisation of aluminium acetals derived from allyl and propargyl alcohols with the parent Ueno-Stork has been made at the BHandHLYP/6-311++G(d,p) level of theory, highlighting mechanistic similarities and differences.
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Affiliation(s)
- Romain Bénéteau
- CEISAM UMR 6230 - UFR des Sciences et des Techniques, Université de Nantes, 2 rue de la Houssinière BP, 92208-44322, Nantes Cedex 3, France
| | - Anne Boussonnière
- CEISAM UMR 6230 - UFR des Sciences et des Techniques, Université de Nantes, 2 rue de la Houssinière BP, 92208-44322, Nantes Cedex 3, France
| | - Jean-Christophe Rouaud
- CEISAM UMR 6230 - UFR des Sciences et des Techniques, Université de Nantes, 2 rue de la Houssinière BP, 92208-44322, Nantes Cedex 3, France
| | - Jacques Lebreton
- CEISAM UMR 6230 - UFR des Sciences et des Techniques, Université de Nantes, 2 rue de la Houssinière BP, 92208-44322, Nantes Cedex 3, France
| | - Jérôme Graton
- CEISAM UMR 6230 - UFR des Sciences et des Techniques, Université de Nantes, 2 rue de la Houssinière BP, 92208-44322, Nantes Cedex 3, France
| | - Denis Jacquemin
- CEISAM UMR 6230 - UFR des Sciences et des Techniques, Université de Nantes, 2 rue de la Houssinière BP, 92208-44322, Nantes Cedex 3, France.,Institut Universitaire de France, 1, rue Descartes, 75231, Paris Cedex 05, France
| | - Muriel Sebban
- Normandie Université, COBRA UMR6014, FR3038, Université de Rouen; INSA de Rouen; CNRS, 76821, Mont-Saint-Aignan Cedex, France
| | - Hassan Oulyadi
- Normandie Université, COBRA UMR6014, FR3038, Université de Rouen; INSA de Rouen; CNRS, 76821, Mont-Saint-Aignan Cedex, France
| | - Ghanem Hamdoun
- Normandie Université, COBRA UMR6014, FR3038, Université de Rouen; INSA de Rouen; CNRS, 76821, Mont-Saint-Aignan Cedex, France
| | - Amber N Hancock
- School of Chemistry and, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, 3010, Australia
| | - Carl H Schiesser
- School of Chemistry and, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, 3010, Australia
| | - Fabrice Dénès
- CEISAM UMR 6230 - UFR des Sciences et des Techniques, Université de Nantes, 2 rue de la Houssinière BP, 92208-44322, Nantes Cedex 3, France.
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Guang J, Hopson R, Williard PG. Diffusion Coefficient-Formula Weight (D-FW) Analysis of 2H Diffusion-Ordered NMR Spectroscopy (DOSY). J Org Chem 2015; 80:9102-7. [DOI: 10.1021/acs.joc.5b01457] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jie Guang
- Department
of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Russell Hopson
- Department
of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Paul G. Williard
- Department
of Chemistry, Brown University, Providence, Rhode Island 02912, United States
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9
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Knorr R, Behringer C, Lattke E, von Roman U, Knittl M. How Microsolvation Numbers at Li Control Aggregation Modes, sp(2)-Stereoinversion, and NMR Coupling Constants (2)JH,H of H2C═C in α-(2,6-Dimethylphenyl)vinyllithium. J Org Chem 2015; 80:6313-22. [PMID: 26029794 DOI: 10.1021/acs.joc.5b00762] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The title compound 4 is a trisolvated monomer 4&3THF in THF solution and dimerizes endothermically to form (4&THF)2 with a strongly positive (!) dimerization entropy in toluene as the solvent. In the absence of electron-pair donor ligands, 4 aggregates (>dimer) in hydrocarbon solutions. These results followed from the (13)C-α splitting patterns and the magnitudes of the one-bond (13)C,(6)Li NMR coupling constants in combination with lithiation NMR shifts as secondary NMR criteria. The rate constants of cis/trans sp(2)-stereoinversion could be measured on the (1)H NMR time scale in THF, in which solvent the preinversion lifetime is 0.24 s at 25 °C. This inversion proceeds according to the pseudomonomolecular, ionic mechanism with the typical, strongly negative pseudoactivation entropy. In a different mechanism, the lifetimes are much longer at 25 °C for the dimer (4&t-BuOMe)2 in toluene (ca. 2.5 min) and for donor-free, aggregated 4 in hexane solution (roughly 1 min). The olefinic interproton two-bond coupling constants (2)JH,H of the H2C═CLi part are proposed as an indicator of microsolvation at Li, because they were found to increase linearly with the "explicit" solvation of α-arylvinyllithiums by 0, 1, 2, and 3 electron-pair donor ligands.
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Affiliation(s)
- Rudolf Knorr
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13 (Haus F), 81377 München, Germany
| | - Claudia Behringer
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13 (Haus F), 81377 München, Germany
| | - Ernst Lattke
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13 (Haus F), 81377 München, Germany
| | - Ulrich von Roman
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13 (Haus F), 81377 München, Germany
| | - Monika Knittl
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13 (Haus F), 81377 München, Germany
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Bluemke TD, Clegg W, García-Alvarez P, Kennedy AR, Koszinowski K, McCall MD, Russo L, Hevia E. Structural and reactivity insights in Mg–Zn hybrid chemistry: Zn–I exchange and Pd-catalysed cross-coupling applications of aromatic substrates. Chem Sci 2014. [DOI: 10.1039/c4sc01263a] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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11
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Rast S, Mohar B, Stephan M. Efficient asymmetric syntheses of 1-phenyl-phosphindane, derivatives, and 2- or 3-oxa analogues: mission accomplished. Org Lett 2014; 16:2688-91. [PMID: 24773070 DOI: 10.1021/ol500970x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A highly enantioselective synthesis of unsubstituted 1-phenyl-phosphindane and its P-borane and P-oxide derivatives was effectively established via a new fluoride-triggered desilylative carbocyclization strategy. Preparation of the "oxygen atom-doped" 1-phenyl-3-oxa-1-phosphindane-P-borane analogue was otherwise achieved via a tandem P-α-iodination-intra-O-alkylation.
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Affiliation(s)
- Slavko Rast
- National Institute of Chemistry , Hajdrihova 19, 1000 Ljubljana, Slovenia
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