New guide for first order multiplet analysis by modified J doubling in the frequency domain

Abstract

Pattern recognition is extremely important for both structure elucidation and stereochemical studies as a means for the measurement of spin-spin coupling constants. Many treatises deal with the formation of splitting trees to create a pattern for a given set of spin-spin coupling constants. We present here a general systematic procedure to easily analyze first order multiplets in NMR spectroscopy. This method has the advantage of measuring coupling constants while deconvolving the signals at the same time using an extension of the modified J doubling in the frequency domain.

Rules for priming and inhibition of glycosaminoglycan biosynthesis; probing the β4GalT7 active site

“…Heteronuclear coupling constants were determined by modied J doubling in the frequency domain. 36 In all cases of the pairwise comparisons for the diastereomeric pairs, 2a and 2b, 3a and 3b, as well as 4a and 4b, we observed larger 3 J CH coupling constants for 2a, 3a, and 4a, compared to 2b, 3b, and 4b. This is consistent with an antiperiplanar arrangement in the former set of molecules.…”

Molecular dynamics simulations and NMR spectroscopy studies of trehalose–lipid bilayer systems

“…Resolution enhancement was achieved in the direct dimension by applying a Lorentzian-to-Gaussian window function (lb = À0.5 Hz and gb = 0.2) to the FIDs. Vicinal 1 H, 1 H couplings were extracted by the analysis of multiplet patterns of cross-peak slices taken in the direct dimension using the J-doubling methodology 66 employing an in-house written Matlab script.…”

“…Homonuclear 1 H, 1 H couplings can be measured from the cross-peak patterns in a phase-sensitive DQF-COSY spectrum 74 where the active coupling appears as an anti-phase doublet and passive couplings appear in-phase. Small couplings are difficult to extract accurately due to the spectral overlap of the multiplet components; however, these J values can be extracted by utilizing the J-doubling methodology, 66 which is based on multiplet deconvolution. One-bond heteronuclear couplings can readily be measured in a 1 H, 13 C-CT-CE-HSQC spectrum, 64 as half of the cross-peak splitting in the indirect dimension (Fig.…”

Experimental and Theoretical Analysis of Vicinal and Long-Range Proton−Proton Coupling Constants for Anthracene Derivatives

“…If the number of delta functions tends to infinity, the whole operation behaves as a formal deconvolution of the signal, which is a linear process. Modified J doubling allowed us to measure very small coupling constants (∼0.3 Hz) even if they are immersed in complex multiples and within the line width at the same time. − This method has the advantage of accurately measuring the magnitude of coupling constants while deconvolving the signals at the same time for nonoverlapped first-order multiplets. At this moment, this is the only method available for the measurement of several small coupling constants immersed in complex multiplets and within the line width.…”