1 / 8

Nuclear Magnetic Resonance

Nuclear Magnetic Resonance. Proton NMR Spectroscopy. Proton NMR. Proton NMR spectrum of the ester, C 7 H 14 O 2 , in banana oil: Note chemical shifts, integration data, multiplicity of signals 4.1 (t, 2H) 2.0 (s, 3H) 1.7 (m, 1H) 1.5 (q, 2H) 0.9 (d, 6H). 1.5 ppm.

ray
Download Presentation

Nuclear Magnetic Resonance

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Nuclear Magnetic Resonance Proton NMR Spectroscopy

  2. Proton NMR • Proton NMR spectrum of the ester, C7H14O2, in banana oil: • Note chemical shifts, integration data, multiplicity of signals • 4.1 (t, 2H) • 2.0 (s, 3H) • 1.7 (m, 1H) • 1.5 (q, 2H) • 0.9 (d, 6H) 1.5 ppm

  3. Characteristic Chemical Shifts • 0 ppm Si(CH3)4 Reference • 0 – 5 ppm H attached to tetrahedral (sp3) carbon • R-CH3 0.8 – 1.0 ppm • R2CH2 1.0 – 1.5 ppm • R3CH 1.5 – 1.8 ppm • RCH2-C(sp2) 1.8 – 2.8 ppm • RCH2-N 2.5 – 3.0 ppm • RCH2-O 3.3 – 3.8 ppm • RCH2-OC(=O)R 3.8 – 4.5 ppm • 5 – 10 ppm H attached to trigonal planar (sp2) carbon • Vinylic 5.0 – 7.0 ppm • Aromatic 6.5 – 8.5 ppm • Aldehyde 9.0 – 10.0 ppm

  4. Spin-Spin Coupling • Each multiplet has one more peak than the sum of the hydrogen atoms on the adjacent carbon atom (N + 1 rule), with a pattern following statistical rules (Pascal’s Triangle). • The separation between each line in the multiplet is the coupling constant, J, in Hz • 5.76 (t, J = 6.0 Hz, 1H) • 3.96 (d, J = 6.0 Hz, 2H) 300 MHz

  5. Effect of Operating Frequency • The coupling constant, J, is independent of the spectrometer operating frequency. • 4.12 (q, J = 7.1 Hz, 2H) • 2.04 (s, 3H) • 1.26 (d, J = 7.1 Hz, 3H) 90 MHz

  6. Protons on Two Adjacent Carbon Atoms • 4.03 (t, 2H) • 2.53 (m, 1H) • 1.65 (m, 2H) • 1.17 (d, 6H) • 0.95 (t, 3H) 90 MHz

  7. Non-equivalent Coupling • 7.50 – 7.10 (5H) • 6.59 (dd, JAB = 15 Hz, JAC = 6 Hz, 1H) • 5.74 (d, JAB = 15 Hz, 1H) • 5.23 (d, JAC = 6 Hz, 1H) • (Note: JBC < 1 Hz) 90 MHz

  8. Protons on O and N • M+ = 75 (2% of bp) • C-13 NMR shifts:60.3, 39.8, 35.5 ppm

More Related