Results 201 to 210 of about 18,999 (260)
Some of the next articles are maybe not open access.
P.E.HSQMBC: Simultaneous measurement of proton–proton and proton–carbon coupling constants
Journal of Magnetic Resonance, 2012A long-range optimized P.E.HSQC experiment, named P.E.HSQMBC, is proposed for the simultaneous measurement of a complete set of homonuclear and heteronuclear coupling constants from a single 2D cross-peak. The sign and the magnitude of proton-proton coupling constants are measured along the direct dimension from the relative E.COSY-type multiplet ...
Josep, Saurí +4 more
openaire +2 more sources
Reliability of protonation constants of SNAZOXS oligomers
Talanta, 1994Concentration protonation constants of variously protonated of oligomers of sulphoazoxine SNAZOXS were determined by regression analysis of potentiometric titration curves. The group and common parameters were estimated using different computational strategies of three regression programs, MINIQUAD, MIQUV and PSEQUAD.
M, Meloun, V, Centner
openaire +2 more sources
Determination of the protonation constant of chloramine-B
Talanta, 1985The protonation constant of chloramine-B has been determined at pH < 3.3 by an ionexchange method. The value found is 61 +/- 5.
M, Subhashini +2 more
openaire +2 more sources
Determination of protonation constants by coulometric titration
Talanta, 1987Application of coulometric titration to the determination of the protonation constants of acids and bases offers several advantages because of its simplicity, precision and accuracy. This procedure is rapid and requires only one calibration solution of strong acid in the same solvent and at the same ionic strength as the solution of acid (or base ...
Głab, Stanisław +2 more
openaire +2 more sources
Vicinal Fluorine–Proton Coupling Constants
Journal of Magnetic Resonance, 1998The angular dependence and the effect of individual substituents upon the NMR vicinal fluorine-proton couplings 3JFH have been studied using data sets of experimental and calculated couplings. Coupling constants for a series of fluoroethane derivatives, CHXF-CH3 and CH2F-CH2X (X = CH3, NH2, OH, and F), were calculated by means of the SCF ab initio and ...
, San Fabian J, , Guilleme, , Diez
openaire +2 more sources
Proton-proton coupling constants in conjugated dienes
Molecular Physics, 1963The proton resonance spectra of two conjugated dienes§ have been analysed to obtain spectral parameters, including 3 J's, 4 J's and in particular the three 5 J's, the coupling interactions across both double bonds. Some of the results differ from those of an earlier investigation and the reasons for this are discussed.
E.O. Bishop, J.I. Musher
openaire +1 more source
Transoid Homoallylic Proton-Proton Coupling Constants
Australian Journal of Chemistry, 1989Transoid homoallylic coupling constants (5JH,H) for six compounds (5,10-dihydroindeno[2,1-alindene and confertifolin derivatives) of fixed stereochemistry were determined and compared with calculated values. Magnetic equivalence limited discrete determination of 5Jtrans and 5Jcis to three of these compounds.
M Barfield, RJ Spear, S Sternhell
openaire +1 more source
Molecular orbital calculations of the proton-proton coupling constants in nucleosides
Journal of Theoretical Biology, 1973Abstract Molecular orbital calculations of proton-proton coupling constants are carried out for a number of nucleosides as a function of conformational characteristics of these compounds. The study of the role of the ring puckering and of the orientation of the exocyclic CH 2 OH group on the vicinal coupling constants of the ribose indicates the ...
C, Giessner-Prettre, B, Pullman
openaire +2 more sources
A priori predictions of the rotational constants for protonated formaldehyde and protonated methanol
Chemical Physics Letters, 1986Protonated formaldehyde and protonated methanol are candidate interstellar molecules and models for classes of protonated oxygen compounds. Ab initio molecular orbital theory has been used to compute rotational constants to guide spectroscopic searches both in the laboratory and in space. The ab initio results are empirically corrected to account for
D J, DeFrees, A D, McLean
openaire +2 more sources
Taurocholate and Taurodeoxycholate: Gel Formation and Protonation Constants
Annali di Chimica, 2006AbstractTaurocholate (TC) and taurodeoxycholate (TDC) in aqueous solutions, in the presence of sodium and hydrogen ions can give micellar products, even differently protonated. This phenomenon is investigated in this paper to explain whether the assumption of hydrogen ions is to attribute to the micellar aggregates, or to the protonation of ...
ANTONILLI, MARCO +2 more
openaire +2 more sources