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Tutorial on 2D-NMR: Using COSY & HSQC to Assist in Assigning 1 H & 13 C NMR Spectra.

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Presentation on theme: "Tutorial on 2D-NMR: Using COSY & HSQC to Assist in Assigning 1 H & 13 C NMR Spectra."— Presentation transcript:

1 Tutorial on 2D-NMR: Using COSY & HSQC to Assist in Assigning 1 H & 13 C NMR Spectra

2 1 H NMR Chemical shift (δ) depends on molecular structure and solvent 1 H nuclei sensitive to hybridization of atom to which H is attached and electronic effects – EDG’s shield nuclei  shift upfield  lower δ – EWG’s deshield nuclei  shift downfield  higher δ 0 ppm 10 ppm Downfield Deshielded Upfield Shielded

3 1 H NMR Spin-spin coupling effects: interaction between nuclei through bonds – Causes splitting in observed peak (s, d, dd, t, m…) – Coupling constants: magnitude of splitting (Hz) Hz (not ppm) since effect is independent of applied mag. fld. Caused by mag. fld. of another nuclei

4 2-D NMR Determine structure (especially for molecules too complicated for 1-D NMR) Involves series of 1-D NMR experiments Doesn’t need to use the complicated coupling constants

5 Correlation Spectroscopy (COSY) Homonuclear: plots 1 H NMR on both x and y-axis Diagonal divides the spectrum into 2 equal halves Cross-signals: symmetrical to diagonal; contain the relevant info FAB-FOUR – 1 H NMR (~5 min) – COSY (~30 min) – 13 C NMR (depends…) – HSQC (~30 min)

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11 3 2 4

12 H3H3 H2H2 H4H4 H3H3 H2H2 H4H4 3 2 4 7 6 8

13 H6H6 H8H8 H7H7 H3H3 H2H2 H4H4 H3H3 H2H2 H4H4 3 2 4 H7H7 H8H8 H6H6 7 6 8 1

14 5 H6H6 H8H8 H7H7 H3H3 H2H2 H4H4 H3H3 H2H2 H4H4 3 2 4 H7H7 H8H8 H6H6 7 6 8 H1H1 H1H1 1

15 H6H6 H8H8 H7H7 H3H3 H2H2 H4H4 H1H1 H5H5 H5H5 H3H3 H2H2 H4H4 H7H7 H8H8 H6H6 H1H1 5 3 2 4 7 6 8 1 11 10 9

16 H 10 H 11 H9H9 H5H5 H3H3 H2H2 H4H4 H7H7 H8H8 H6H6 H1H1 H 10 H 11 H9H9 H6H6 H8H8 H7H7 H3H3 H2H2 H4H4 H1H1 H5H5 5 3 2 4 7 6 8 1 11 10 9

17 LONG-RANGE COUPLING H 10 H 11 H9H9 H5H5 H3H3 H2H2 H4H4 H7H7 H8H8 H6H6 H1H1 H 10 H 11 H9H9 H6H6 H8H8 H7H7 H3H3 H2H2 H4H4 H1H1 H5H5 5 3 2 4 7 6 8 1 11 10 9

18 Heteronuclear Single Quantum Coherence (HSQC) Plots 1 H NMR on x-axis and 13 C NMR on y-axis Utilizes 1 bond coupling between H and C Eliminating all the H containing C’s eliminates many C’s assignments – Leaves only on-H containing C’s to assign

19 HSQC Spectrum

20 H 10 H 11 H9H9 H5H5 H3H3 H2H2 H4H4 H7H7 H8H8 H6H6 H1H1 5 3 2 4 7 6 8 1 11 10 9

21 H 10 H 11 H9H9 H5H5 H3H3 H2H2 H4H4 H7H7 H8H8 H6H6 H1H1 5 3 2 4 7 6 8 1 11 10 9

22 # of total peaks:131425 # of non-H C peaks:110102 C1C1 C5C5 C 10 C3C3 C7C7 C 11 C2C2 C6C6 C4C4 C8C8 C9C9 C 12 C 13 ?????????? C 12, C 13, C 14, C 15, C 17 ?????????? C 14, C 15, C 17

23 Thank You Any Questions?


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