Aqueous solution interaction of the methylmercuric cation with the dinucleotides CpG and dCpdG as studied by carbon-13 nuclear magnetic resonance spectroscopy

1986 ◽  
Vol 64 (10) ◽  
pp. 2038-2041 ◽  
Author(s):  
G. W. Buchanan ◽  
M. J. Bell
Keyword(s):  
Aqueous Solution ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
The Self ◽  
Coupling Constants ◽  
Resonance Spectroscopy ◽  
Spectral Parameters ◽  
Guanine Base ◽  
Nuclear Magnetic

13C nuclear magnetic resonance chemical shifts and 13C–31P coupling constants are reported for the self-complementary dinucleotides CpG and dCpdG in aqueous solution. The influence of methylmercuration at pH 6.0 on these spectral parameters has been examined. Results are interpreted in terms of preferential methylmercuration at the N-7 site of the guanine base of each dinucleotide with concomitant base destacking.

Studies of specifically fluorinated carbohydrates. Part I. Nuclear magnetic resonance studies of hexopyranosyl fluoride derivatives

1969 ◽  
Vol 47 (1) ◽  
pp. 1-17 ◽  
Author(s):  
L. D. Hall ◽  
J. F. Manville ◽  
N. S. Bhacca
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Angular Dependence ◽  
Chemical Shifts ◽  
Relative Orientation ◽  
Coupling Constants ◽  
Pyranose Ring ◽  
Spectral Parameters ◽  
Magnetic Resonance Studies ◽  
Nuclear Magnetic

A detailed study has been made of both the 1H and 19F nuclear magnetic resonance (n.m.r.) spectra of a series of hexopyranosyl fluoride derivatives. Some of the 1H spectra were measured at 220 MHz. The 1H spectral parameters define both the configuration and the conformation of each of these derivatives. Study of the 19F n.m.r. parameters revealed several stereospecific dependencies. The 19F chemical shifts depend upon, (a) the orientation of the fluorine substituent with respect to the pyranose ring and, (b) the relative orientation of other substituents attached to the ring; for acetoxy substituents, these configurational dependencies appear to be additive. The vicinal19F–1H coupling constants exhibit a marked angular dependence for which Jtrans = ca. 24 Hz whilst Jgauche = 1.0 to 1.5 Hz for [Formula: see text] and 7.5 to 12.6 Hz for [Formula: see text] The geminal19F–1H couplings depend on the orientation of the substituent at C-2; when this substituent is equatorial JF,H is ca. 53.5 Hz and when it is axial the value is ca. 49 Hz.

Studies of specifically fluorinated carbohydrates. Part II. Nuclear magnetic resonance studies of pentopyranosyl fluoride derivatives

1969 ◽  
Vol 47 (1) ◽  
pp. 19-30 ◽  
Author(s):  
L. D. Hall ◽  
J. F. Manville
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Resonance Spectroscopy ◽  
Magnetic Resonance Studies ◽  
Conformational Model ◽  
Nuclear Magnetic

Detailed studies, by 1H and 19F nuclear magnetic resonance spectroscopy, of a series of fully esterified pentopyranosyl fluorides, show that all such derivatives favor that conformer in which the fluorine substituent is axially oriented. This conclusion is supported by separate considerations of the vicinal and geminal19F–1H and 1H–1H coupling constants, of the long-range (4J) 1H–1H and 19F–1H coupling constants and of the 19F chemical shifts. The limitations of the above conformational model are discussed.

Nuclear magnetic resonance spectral parameters of α,α,α-trifluorotoluene

1969 ◽  
Vol 47 (18) ◽  
pp. 3313-3318 ◽  
Author(s):  
R. J. Kostelnik ◽  
M. P. Williamson ◽  
D. E. Wisnosky ◽  
S. M. Castellano
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Spectral Data ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Spectral Parameters ◽  
Nuclear Magnetic

The 60 and 100 MHz proton spectra of α,α,α-trifluorotoluene have been recorded and analyzed in terms of chemical shifts and coupling constants. The results of the analyses are compared and the values of the spectral parameters discussed. The nuclear magnetic resonance spectral data of 2-chloro-5-nitro-α,α,α-trifluorotoluene are also reported.

Review lecture: Nuclear magnetic resonance spectroscopy in two frequency dimensions

1980 ◽  
Vol 373 (1753) ◽  
pp. 149-178 ◽  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Past History ◽  
Dimensional Space ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Resonance Spectroscopy ◽  
Experimental Conditions ◽  
Nuclear Magnetic

A spectrum is normally thought of in terms of a graph of absorption intensity as a function of frequency, and in this form it has served us well for many years. A recent development extends this idea into a second frequency dimension, the spectrum now being represented by a surface in three-dimensional space. The examples are in the field of high resolution nuclear magnetic resonance (n.m.r.) spectroscopy, although the principle is rather more general, being based on the two-dimensional Fourier transformation of a transient response that is a function of two independent time variables t 1 and t 2 . By arranging for different experimental conditions to prevail during t 1 and t 2 , it is possible to separate different n.m.r. parameters, for example chemical shifts and spin coupling constants, into the two frequency dimensions. There is also an important element of correlation involved, since during t 2 the nuclei ‘remember’ their past history during t 1 ,and this has been used to correlate proton and carbon-13 chemical shifts.

NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY OF SOME SELENIUM COMPOUNDS

1965 ◽  
Vol 43 (6) ◽  
pp. 1672-1679 ◽  
Author(s):  
T. Birchall ◽  
R. J. Gillespie ◽  
S. L. Vekris
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Resonance Spectroscopy ◽  
Arsenic Trichloride ◽  
Selenium Compounds ◽  
Nuclear Magnetic Resonance Spectra ◽  
Tin Tetrachloride ◽  
Nuclear Magnetic

Selenium nuclear magnetic resonance spectra have been observed for a number of selenium compounds. Chemical shifts and coupling constants with hydrogen and fluorine have been obtained. Various systems involving selenium compounds have been studied. It was found that a mixture of SeOF2 and SeOCl2 contains SeOClF and that rapid selenium exchange occurs between SeOCl2 and SeOBr2 presumably via the intermediate SeOClBr. The reactions of selenium tetrahalides with sulfur and selenium trioxides and with boron trifluoride were studied. It was observed that antimony pentachloride, tin tetrachloride, arsenic trichloride, quinoline, and potassium chloride produce considerable shifts in the resonance of selenium oxychloride. These shifts can be interpreted in terms of the acid–base behavior of the solutes.

Studies of fluoroberyllate complexes in aqueous solution by I9F nuclear magnetic resonance

1970 ◽  
Vol 48 (19) ◽  
pp. 2960-2964 ◽  
Author(s):  
M. G. Hogben ◽  
K. Radley ◽  
L. W. Reeves
Keyword(s):  
Aqueous Solution ◽  
Nuclear Magnetic Resonance ◽  
Melting Point ◽  
Magnetic Resonance ◽  
Room Temperature ◽  
Chemical Shifts ◽  
Equilibrium Constants ◽  
Coupling Constants ◽  
Intensity Measurements ◽  
Nuclear Magnetic

Studies of aqueous solutions containing fluoride and beryllium ion in ratios between 5 and 0.5 were made by 19F nuclear magnetic resonance at temperatures between the melting point of solutions and room temperature. Signals clearly identifiable as arising from BeF42−, BeF3−, BeF2, and BeF+ were assigned. Chemical shifts and coupling constants JBe–F are reported for all species and approximate equilibrium constants are determined from intensity measurements for the reactions [Formula: see text] [Formula: see text] and [Formula: see text]

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