Download as PDF, PPTX
Uploaded byNasir Uddin
92d 160213100731
2-D NMR provides more information than 1-D NMR by collecting data in two frequency dimensions rather than one. It involves applying two pulses separated by a short evolution period to excite nuclei. This results in two free induction decay signals which are Fourier transformed to yield a spectrum with frequencies plotted on two axes. The peaks reveal correlations between different nuclear spins, such as proton-proton correlations seen in COSY spectra or proton-carbon correlations seen in HETCOR spectra. 2-D NMR is useful for analyzing complex macromolecules that have overlapping peaks in 1-D NMR.
More Related Content
Similar to 92d 160213100731
92d 160213100731
- 1. Two- Dimensional NMR OR 2-DNMR Mussawir Ali Mirza Roll No. 16 University of Punjab
- 2. OBJECTIVES 1) 1-D NMR Principle SequenceScheme Name Proposed 2) 2-D NMR Principle Sequence Scheme Name proposed shapes of Signal Why 2D NMR Types
- 3. 1-D NMR • SimpleFT-NMR Technique • 1-D NMR spectroscopy is simple technique In which we provide 90 degree pulse to sample which is placed in uniform magnetic field. As a result we get a FID signal (raw form). To get meaningful data we apply Fourier Transform program on FID to get desire signal. • Data in form of frequency vs intensity is plotted along x-axis and y-axis respectively
- 4.
- 5. Sequence Scheme If wedivide the 1-D NMR into a general periods , we get two steps •Preparation •Detection Preparation : (do something with nuclei) What we can do ??? •Simply we provide a 90 degree pulse Detection: ( detect the signal) •Simply we measure the signal
- 6.
- 7. Why Named 1-DNMR ?? • We call it 1-D NMR , not because of graph. Graph is actually in 2-d. • Since one of the time domain is changing into frequency dimension, That’s why we call it 1D NMR, Time dimension changing into frequency dimension
- 8. 2-D NMR • Thefirst two-dimensional experiment was proposed by Jean Jenner. • 2D NMR is a set of nuclear magnetic resonance spectroscopy (NMR) methods which give data plotted in a space defined by two frequency axes rather than one. • 2D NMR spectra provide more information about a molecule than one-dimensional NMR spectra.
- 9. Principle • 2D NMRis Nuclear magnetic resonance spectroscopy in which we provide a 90 degree pulse to our sample which is placed in uniform magnetic field then we wait for (0ms-5ms) depending upon the experiment type then again we provide again 90 degree pulse and this time we measure signal as FID. • As a result we get Two FID signals which are plotted with respect to time domain. • To get a meaningful data , we apply Fourier transform program on FIDs to get frequency in terms of ppm.
- 10. 1. Primary 2Dmatrix consists a series of FIDs. 2. A set of 1D NMR spectra is obtained by Fourier transformation with respect to t2 3. The signals of each transformation may differ in amplitude and phase. A second Fourier transformation with respect to t1 yields the final 2D matrix with frequency axes F1 and F2 1. 2. 3. 2D NMR
- 11.
- 12. PreparationPreparation:: 90 degreepulse excite nuclei in sample. EvolutionEvolution (t1): let them nuclei precess freely. MixingMixing: again 90 degree r.f. pulses are applied and create transverse magnetization DetectionDetection (t2): observable transverse magnetization is recorded. It is usually labeled with t2 Four periods in 2D experiment
- 13.
- 14. How 2D Spectrumis Recorded
- 15. How Data isProceeded
- 16.
- 17.
- 18.
- 19.
- 20. Why 2D NMR •As 1D NMR spectrum of Macromolecules is quite complex. • So make this complex spectrum easy, we use 2D NMR.
- 21. Types of 2DNMR • Homonuclear Experiment : In this experiment we provide two frequency to same nuclei in sample. i.e. H-H Correlation spectroscopy (COSY) Actually in it we basically see homonuclear connectivity between same nuclei. • Heteronuclear Experiment : In this experiment wo provides two frequency to different nuclei in the sample i.e. H-C Heteronuclear Correlation (HETCOR).
- 22.
- 23.
- 24.
- 25.