Applications of the intermolecular nuclear Overhauser effect. II. The operation of solute-site factors in the interaction of polar solutes with the solvent benzene

1983 ◽  
Vol 36 (11) ◽  
pp. 2227 ◽  
Author(s):  
GR Smith ◽  
B Ternai
Keyword(s):  
Nuclear Overhauser Effect ◽  
Proton Relaxation ◽  
Relaxation Rates ◽  
Site Factors ◽  
Aromatic Solvent ◽  
Proton Proton ◽  
Solvent Interactions ◽  
Overhauser Effect ◽  
Polar Solutes ◽  
Nuclear Overhauser

By considering the technique involving the measurement of aromatic solvent-induced shifts, and the models which have been proposed from the results of such measurements, it is suggested that the use of the solvent-induced solute proton intermolecular relaxation rate [(1/T1)solvinter] is a better method to study local solvation of solute molecules. Proton relaxation rates obtained for simple solutes in the solvent benzene are analysed in terms of an interaction parameter I, which treats (1/T1)solvinter] in terms of a proton-proton pair distribution function. The resultant dependence between I and a calculated measure of the local polarity of the observed solute is discussed in terms of previously proposed models of solute-solvent interactions.

Applications of the intermolecular nuclear Overhauser effect. I. Determination of differential solvent effects: the hydration of pyridine

1983 ◽  
Vol 36 (3) ◽  
pp. 493 ◽  
Author(s):  
GR Smith ◽  
B Ternai
Keyword(s):  
Nuclear Overhauser Effect ◽  
Water System ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Alternative Methods ◽  
Relaxation Rates ◽  
Overhauser Effect ◽  
Nuclear Overhauser ◽  
Intermolecular Relaxation

The intermolecular relaxation rates of the pyridine-water system have been obtained by the measurement of the total spin lattice relaxation rate and the intermolecular nuclear Overhauser effect between pyridine and water, for each pyridine proton. The advantages of this method for the determination of the intermolecular relaxation rates are discussed, and the method is compared with alternative methods. The results indicate that there is a varying degree of hydration about the pyridine molecule, with the nitrogen being the preferred site of water interaction. It is necessary to interpret the results in terms of solute-solute as well as solute-solvent interactions. A model is proposed which takes account of both types of interaction, and is considered in terms of previously proposed models of pyridine-water interactions.

Solute—Solvent Interactions Examined by the Nuclear Overhauser Effect

ChemInform ◽  
2007 ◽  
Vol 38 (37) ◽  
Author(s):  
J. T. Gerig
Keyword(s):  
Nuclear Overhauser Effect ◽  
Solvent Interactions ◽  
Overhauser Effect ◽  
Nuclear Overhauser

scholarly journals An investigation into the solution structures of two self-complementary DNA oligomers, 5′-d(C-G-T-A-C-G) and 5′-d(A-C-G-C-G-C-G-T), by means of nuclear-Overhauser-enhancement measurements

1984 ◽  
Vol 221 (3) ◽  
pp. 723-726 ◽  
Author(s):  
A M Gronenborn ◽  
G M Clore ◽  
B J Kimber
Keyword(s):  
Nuclear Overhauser Effect ◽  
Type Structure ◽  
Dna Oligomers ◽  
Proton Proton ◽  
Solution Structures ◽  
Interproton Distance ◽  
Overhauser Effect ◽  
Distance Data ◽  
Nuclear Overhauser ◽  
Interproton Distances

A 500 MHz 1H-n.m.r. study on two self-complementary alternating pyrimidine-purine oligodeoxyribonucleotides, 5′-d(C-G-T-A-C-G) and 5′-d(A-C-G-C-G-C-G-T), is presented. By using the proton-proton nuclear Overhauser effect virtually complete assignments are obtained and a large number of interproton distances [113 in the case of 5′-d(C-G-T-A-C-G) and 79 in the case of 5′-d(A-C-G-C-G-C-G-T)], both intra- and inter-nucleotide, are determined. The interproton-distance data are consistent with an overall right-handed B-DNA-type structure for both oligonucleotides, in agreement with their B-type c.d. spectra. However, whereas 5′-d(C-G-T-A-C-G) adopts a conventional B-type structure with a mononucleotide repeating unit, the interproton-distance data provide evidence that 5′-d(A-C-G-C-G-C-G-T) has a dinucleotide repeating unit consisting of alternation in glycosidic bond and sugar pucker conformations.

The synthesis and the nuclear magnetic resonance study of β-lactam derivatives of 1,5-benzothiazepines

1988 ◽  
Vol 66 (2) ◽  
pp. 279-282 ◽  
Author(s):  
Aron Szöllösy ◽  
George Kotovych ◽  
Gábor Tóth ◽  
Albert Lévai
Keyword(s):  
Nuclear Overhauser Effect ◽  
Nuclear Magnetic Resonance Study ◽  
Coupling Constants ◽  
Magnetic Resonance Study ◽  
Proton Proton ◽  
Proton Coupling ◽  
Overhauser Effect ◽  
Vicinal Proton ◽  
Nuclear Overhauser ◽  
Derivatives Of

The synthesis and stereochemistry of seven β-lactam derivatives of 1,5-benzothiazepines are presented. The configurational and conformational analysis is based on nuclear Overhauser effect experiments, together with analysis of the vicinal proton–proton coupling constants. In the preferred conformation, the seven-membered ring is in a half-chair. Only for one compound, 2-aza-4-bromo-4-methyl-5,7-diphenyl-8-thiatricyclo[7.4.0.02,5]trideca-Δ1,9,10,12-trien-3-one, were two diastereomers isolated (compounds 6a and 6b). Six of the compounds have the 4S*, 5R*, 7R* configuration while compound 6b has the 4R*, 5R*,7R* configuration.

The conformational analysis of leukotriene D4 in aqueous solution based on high-field nuclear magnetic resonance measurements

1984 ◽  
Vol 62 (8) ◽  
pp. 1640-1645 ◽  
Author(s):  
Makiko Sugiura ◽  
Helmut Beierbeck ◽  
George Kotovych ◽  
Patrice C. Bélanger
Keyword(s):  
Conformational Analysis ◽  
Nuclear Overhauser Effect ◽  
Relaxation Times ◽  
Coupling Constants ◽  
Leukotriene D4 ◽  
Proton Proton ◽  
Proton Coupling ◽  
Overhauser Effect ◽  
Vicinal Proton ◽  
Nuclear Overhauser

The conformational analysis of LTD4 in D2O was carried out based on the analysis of vicinal proton–proton coupling constants, nonselective proton longitudinal relaxation times, and nuclear Overhauser effect data. The H6—C6 to C12 region of the molecule is transoid, the predominant rotamer about C5—C6 is gauche, and two rotamers can be used to describe the rotation about C12—C13. There are three rotamers that can be used to describe the rotation about the C21—C22 bond of cysteine. Finally, chelation between an Yb3+, shift reagents and LTD4 was not observed.

scholarly journals Conformations of 3-Deazaadenosine, 3-Deaza-8-azaadenosine, and Benzimidazole-1-β-ᴅ-riboside in Solution: HRNMR-, Proton-Relaxation-Time-, and Nuclear-Overhauser- Effect Studies

1978 ◽  
Vol 33 (5-6) ◽  
pp. 305-316 ◽  
Author(s):  
H.-D. Lüdemann ◽  
H. Pladi ◽  
E. Westhof ◽  
L. B. Townsend
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Relaxation Time ◽  
Magnetic Resonance ◽  
Nuclear Overhauser Effect ◽  
Proton Relaxation ◽  
Proton Relaxation Time ◽  
Nuclear Overhauser Enhancement ◽  
Overhauser Effect ◽  
Nuclear Overhauser ◽  
Ribose Moiety

The solution conformations of 3-deazaadenosine, 3-deaza-8-azaadenosine, and benzimidazole-1-β- ᴅ-riboside have been determined by nuclear magnetic resonance methods in aqueous and ammonia solutions. The two-state S ⇄ N model of Altona and Sundaralingam is used to analyse the ribose moiety. In order to characterize the orientation of the base relative to the ribose, longitudinal proton relaxation time and nuclear Overhauser enhancement measurements have been carried out. It is shown that 3-deazaadenosine and benzimidazole-1-β-ᴅ-riboside exist preferentially in the S- syn-g+/t (70%) and the N-anti-g+/t (30%) conformation families. In the case of 3-deaza-8-aza- adenosine, some destabilization of the g+rotamer occurs. In this case, the pulsed methods seem to indicate a preference of the base for the anti range.

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