𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Measurements of Long-Range Homonuclear Coupling Constants

✍ Scribed by L. Mahi; J. C. Duplan

Publisher
John Wiley and Sons
Year
1997
Tongue
English
Weight
245 KB
Volume
35
Category
Article
ISSN
0749-1581

No coin nor oath required. For personal study only.

✦ Synopsis

Coupling constants in proton systems provide access to useful structural information. Several methods have been proposed to measure these constants in high-resolution spectra, but many of them are not well suited when the coupling constants are comparable to the spectral linewidth. In such a case the measurement of the apparent splitting, obtained from conventional NMR or from two-dimensional correlation spectroscopy (COSY), can cause a miscalculation of the true coupling constant value. In this work, data processing for extracting small coupling constants is described. Signals are obtained from spin-echo experiments and analysed in the time domain in such a way that couplings are apparently multiplied by n + 1, where n is positive. Small coupling constants in 4-methyl-1,3-dioxane were obtained by this method.

📜 SIMILAR VOLUMES

Measurement of long-range proton—carbon
Measurement of long-range proton—carbon coupling constants in medium-sized molecules
✍ Miloš Hricovíni; Tibor Liptaj 📂 Article 📅 1989 🏛 John Wiley and Sons 🌐 English ⚖ 295 KB 👁 1 views

A m d i e d version of the two-dimensional semiselective INEPT experiment is presented which allows the determination of long-range protowarbon couplings in medium-sized molecules. The difference in the TI relaxation times is utilized for the reduction of the number of protons from which coherence i

Long range 13C1H coupling constants. III
Long range 13C1H coupling constants. III—methylpyridines
✍ Yoshito Takeuchi 📂 Article 📅 1975 🏛 John Wiley and Sons 🌐 English ⚖ 312 KB 👁 1 views

## Abstract Proton coupled carbon‐13 NMR spectra of eleven mono‐, di‐ and trimethylpyridines were analysed on a first order basis. The long range ^13^C^1^H coupling constants are similar to those observed for pyridine and cyanopyridines.

Direct measurement of heteronuclear long
Direct measurement of heteronuclear long-range coupling constants from phase-sensitive HMBC spectra
✍ Keyang Ding 📂 Article 📅 2000 🏛 John Wiley and Sons 🌐 English ⚖ 54 KB 👁 1 views

A simple pulse sequence in inverse-detection mode is proposed for the detection of heteronuclear long-range couplings. In the resulting 2D heteronuclear multiple-bond correlation (HMBC) spectra, pure-absorptive peak patterns are obtained along both frequency dimensions. Since the heteronuclear coupl

Hadamard Long-Range Proton–Carbon Coupli
Hadamard Long-Range Proton–Carbon Coupling Constant Measurements with Pulsed Field Gradients
✍ T. Nishida; G. Widmalm; P. Sándor 📂 Article 📅 1996 🏛 John Wiley and Sons 🌐 English ⚖ 416 KB 👁 1 views

## Sources of artifacts in Hadamard spectra were investigated and identified as insufficient suppression of signals from solvent, protons attached to "C atoms and error signals caused by non-ideal excitation and the subsequent Hadamard transformation. Pulsed field gradients (PFG) effectively elimi