Lecture 9 - NMR spectroscopy 1 TODAY 1 1 2 3 Intro to...

Info icon This preview shows pages 1–12. Sign up to view the full content.

View Full Document Right Arrow Icon
NMR spectroscopy 1
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
TODAY Intro to NMR (Slides 3 – 10). Three fundamental NMR Parameters: 1. Chemical shift (ppm scale) 2 2. Intensity information 3. Nearest neighbour analysis Problem Solving
Image of page 2
The World’s Premier Antifungal Drug How is the structure of this molecule determined? 3
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
1 H NMR spectrum of Amphotericin B methyl ester (Professor Jeff Manthorpe) The structure of amphotericin B is determined by NMR ! 4 Spectrum obtained for Professor Jeff Manthorpe
Image of page 4
NMR in CONTEXT: Information on molecular structure is typically obtained using ~ 4 routine spectroscopic methods: 1. UV-Vis (for conjugated systems). 2. IR (for certain functional groups). O O 5 3. Mass spectrometry (MS) (for molecular weight and the weight of fragments). C n H m OSNX 4. Nuclear magnetic resonance (NMR) gives detailed structural information (including Stereochemistry). OH H
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Organic Chemists mainly rely on two methods of NMR analysis 1 H (proton (hydrogen) NMR) 13 C (carbon NMR) – Note: 12 C nuclei not detected by NMR 6 Also possible to detect: 19 F, 14 N, 17 O, 2 H (D), 31 P *NMR observable nuclei have odd mass or odd atomic number, or both
Image of page 6
NMR “experiment” In the presence of an applied magnetic field (B), NMR-active nuclei (e.g. 1 H) align their magnetic moment vectors ( μ ) with or opposed to the field. 7 opposed to the field. B μ or This generates two spin states E 10 6 10 6 + 1 Small excess in lower state
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
NMR instrument Spin 8 Note: MRI - magnet rotates; Sample is stationary
Image of page 8
Generate a 1 H or 13 C spectrum Intensity Observe Absorption of Rf energy ( E) E 9 B lo B hi B (magnetic field strength)
Image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
E α B (Bloch equation) E We have to select the proper magnetic field strength to observe 10 (MHz) B (magnetic field strength) spin flip and the absorption of Rf energy (resonance). Rf frequency ( E) is fixed and the magnetic field strength is varied. B hi B lo
Image of page 10
Three fundamental NMR Parameters give useful structural information 1. Chemical shift (ppm scale) – gives functional group information.
Image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 12
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern