Diffusion NMR Spectroscopy in Supramolecular and Combinatorial Chemistry: An Old Parameter — New Insights

Cohen, Yoram; Avram, Liat; Frish, Limor

doi:10.1002/chin.200519294

Cited by 40 publications

(57 citation statements)

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“…Self-diffusion coefficients have been converted into molecular hydrodynamic dimensions using Equation (1). It is generally accepted that self diffusion coefficients determined by NMR are very close to translational diffusion coefficients determined e.g., by isothermal translation diffusion in the case of diluted solutions [15,16]. corresponds to protons of -CO-CH-NH-group, the peak at 3.13 ppm corresponds to protons of -CH 2 -NH-CO-group, peak at 2.93 ppm relates to -CH 2 -NH 3 + terminal groups, the other peaks correspond to -(CH 2 ) n -.…”

Section: Methodsmentioning

confidence: 99%

Hydrodynamic Behavior of Dendrigraft Polylysines in Water and Dimethylformamide

et al. 2012

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Abstract:The four first generations of dendrigraft poly-L-lysine have been studied in dimethylformamide (aprotic solvent) and in 0.2 M NaCl aqueous solutions by isothermal translation diffusion, 1 H NMR and viscometry methods. The relationships between diffusion coefficient, intrinsic viscosity and molar mass have been determined for dendrigraft poly-L-lysines, and the scaling index values have been compared to classical trifunctional dendrimers. Dendrimers and dendrigraft poly-L-lysines exhibited similitudes in their hydrodynamic behaviors. Nevertheless, dendrigraft poly-L-lysines displayed a specific behavior in solution. In contrast to dendrimers, a significant change of hydrodynamic dimension of dendrigraft poly-L-lysines according to the nature of the solvent has been observed. In aprotic solvent, the dendrigraft poly-L-lysine dimensions are about two times lower than in aqueous media (i.e., the hydrodynamic volume is contracted by a factor 8 in dimethylformamide), revealing the softness of dendrigraft poly-L-lysine compared to classical trifunctional dendrimers. OPEN ACCESSPolymers 2012, 4 21

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Section: Methodsmentioning

confidence: 99%

Hydrodynamic Behavior of Dendrigraft Polylysines in Water and Dimethylformamide

et al. 2012

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“…The product b 5 k 2 ÁD is the critical factor that determines the minimum diffusion coefficient D that can be fitted from data obtained from a PFG-NMR experiment, i.e., the lower D the higher the required values for b. The development of SS-DOSY makes it possible to use the available gradient durations and strengths for the study of slowly diffusing species, such as large molecules, molecules of nonspherical shape with large radii of gyration [such as unfolded molecules and molten globules (27)] or tumbling in highly viscous media, resembling the interior of the cells (28); it is also often the case of supramolecular assemblies (29).…”

Section: Studies Of Diffusion Via Singlet Statesmentioning

confidence: 99%

Singlet states open the way to longer time‐scales in the measurement of diffusion by NMR spectroscopy

Cavadini

Vasos

2008

Concepts Magnetic Resonance

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Nuclear magnetic resonance is a powerful nonintrusive technique for measuring diffusion coefficients through the use of pulsed field gradients. The main limitation to the application range of this method is imposed by the relaxation time constants of the magnetization. The recently introduced singlet-state spectroscopy affords obtaining relaxation time constants for pairs of coupled spins which can be longer by more than an order of magnitude than the spin-lattice relaxation time constants. We review in this paper the advantages that are offered by these long relaxation time constants for diffusion measurements. Using experiments that combine singlet-state and diffusion spectroscopy, slower diffusion constants can be determined. The coupling of the two methods constitutes an alternative to the use of special probes equipped with strong gradients for the study of large molecules that diffuse slowly in solution.

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“…The 2D NMR techniques have become popular since they efficiently map out 3D interactions within, or sometimes between, molecules [18]. The diffusion ordered spectroscopy (DOSY) technique is a non-invasive powerful technology that has been used for the analysis of a large variety of mixtures [19], as well as for the characterization of aggregates of varying sizes and hence different diffusion coefficients (DC) [20].…”

Section: Introductionmentioning

confidence: 99%

Monitoring the functionalization of single-walled carbon nanotubes with chitosan and folic acid by two-dimensional diffusion-ordered NMR spectroscopy

Castillo

Torres

Molina

et al. 2012

Carbon

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Monitoring the functionalization of single-walled carbon nanotubes with chitosan and folic acid by two-dimensional diffusion-ordered nmr spectroscopy, Carbon (2012), doi: 10.1016/j.carbon. 2012.02.010 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Monitoring the functionalization of single-walled carbon nanotubes with chitosan and folic acid by two-dimensional diffusion-ordered nmr spectroscopy ABSTRACTA conjugate between single-walled carbon nanotubes, chitosan and folic acid has been prepared. It was characterized by diffusion ordered two-dimensional hydrogen-1 nuclear magnetic resonance and hydrogen-1 nuclear magnetic resonance spectroscopy which revealed the presence of a conjugate that was generated by the linkage between the carboxyl moiety of the folic acid and the amino group of the chitosan, which in turn was non-covalently bound to the single-walled carbon nanotubes. The obtained diffusion coefficient values demonstrated that free folic acid diffused more rapidly than the folic acid conjugated to single-walled carbon nanotubes-chitosan. The values of the proton signal of hydrogen-1 nuclear magnetic resonance spectroscopy and two-dimensional hydrogen-1 nuclear magnetic resonance spectroscopy further confirmed that the folic acid was conjugated to the chitosan, wrapping the single-walled carbon nanotubes.

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Diffusion NMR Spectroscopy in Supramolecular and Combinatorial Chemistry: An Old Parameter — New Insights

Abstract: For Abstract see ChemInform Abstract in Full Text.

Cited by 40 publications

References 1 publication

Hydrodynamic Behavior of Dendrigraft Polylysines in Water and Dimethylformamide

Hydrodynamic Behavior of Dendrigraft Polylysines in Water and Dimethylformamide

Singlet states open the way to longer time‐scales in the measurement of diffusion by NMR spectroscopy

Monitoring the functionalization of single-walled carbon nanotubes with chitosan and folic acid by two-dimensional diffusion-ordered NMR spectroscopy

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