השוואת שיטות

	NOESY	HSQC	הד-ספין ב-NMR
תחום	ספקטרוסקופיה	ספקטרוסקופיה	ספקטרוסקופיה
משפחה	Process / pipeline	Process / pipeline	Process / pipeline
שנת המקור	1981	1980	1950
הוגה השיטה	Richard Ernst	Anil Kumar	Erwin Hahn
סוג	Two-dimensional pulse sequence	Heteronuclear correlation sequence	Spectroscopic pulse sequence
מקור מכונן	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.	Bodenhausen, G., & Ruben, D. J. (1981). Natural abundance nitrogen-15 NMR by enhanced heteronuclear spectroscopy. Chemical Physics Letters, 69(2), 185-189.	Hahn, E. L. (1950). Spin echoes. Physical Review, 80(4), 580-594.
כינויים	NOE spectroscopy, 2D NOESY, NOE NMR	HSQC NMR, 1H-13C HSQC, heteronuclear correlation	CPMG pulse sequence, spin-echo NMR
קשורות	3	4	4
תקציר	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.	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.	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.