Compara mètodes

	Ressonància Magnètica Nuclear (RMN) Spin-Echo	HSQC	NOESY
Camp	Espectroscòpia	Espectroscòpia	Espectroscòpia
Família	Process / pipeline	Process / pipeline	Process / pipeline
Any d'origen	1950	1980	1981
Autor original	Erwin Hahn	Anil Kumar	Richard Ernst
Tipus	Spectroscopic pulse sequence	Heteronuclear correlation sequence	Two-dimensional pulse sequence
Font seminal	Hahn, E. L. (1950). Spin echoes. Physical Review, 80(4), 580-594.	Bodenhausen, G., & Ruben, D. J. (1981). Natural abundance nitrogen-15 NMR by enhanced heteronuclear spectroscopy. Chemical Physics Letters, 69(2), 185-189.	Aue, W. P., Bartholdi, E., & Ernst, R. R. (1976). Two-dimensional spectroscopy. Application to nuclear magnetic resonance. The Journal of Chemical Physics, 64(5), 2229-2246.
Àlies	CPMG pulse sequence, spin-echo NMR	HSQC NMR, 1H-13C HSQC, heteronuclear correlation	NOE spectroscopy, 2D NOESY, NOE NMR
Relacionats	4	4	3
Resum	The spin-echo is a fundamental nuclear magnetic resonance (NMR) pulse sequence technique introduced by Erwin Hahn in 1950. It uses a 90-degree radiofrequency pulse followed by a 180-degree refocusing pulse to create an echo, effectively reversing the effects of magnetic field inhomogeneities and allowing accurate measurement of spin relaxation properties. This technique is essential in modern NMR spectroscopy for both one-dimensional and multidimensional experiments.	Heteronuclear Single-Quantum Coherence (HSQC) is a 2D NMR technique that correlates proton and carbon-13 (or other heteronuclei) chemical shifts through one-bond coupling constants (1JHX). Developed in the early 1980s, HSQC rapidly became the workhorse of structural chemistry because it directly maps which carbons bear which protons, providing a comprehensive view of carbon skeleton connectivity and substitution patterns.	Nuclear Overhauser Enhancement Spectroscopy (NOESY) is a 2D NMR technique that detects through-space dipolar coupling between protons, rather than through-bond scalar coupling. Introduced by Macura and Ernst in 1981, NOESY reveals which protons are spatially close in the three-dimensional structure, independent of bonding connectivity. This makes NOESY invaluable for determining molecular conformation, assigning stereochemistry, and elucidating protein folds.