NMR

Nuclear Magnetic Resonance

• soft tissue and organs

• no damage through radiation

• MALDI-MS

• x-ray crystallography

• electron microscopy

• organisms: for example humans —> made of organs, tissue and cells

• in cell NMR:

  • DNA and RNA

  • proteins

  • lipids / hydrocarbons

• polymers and macromolecules

• solids: solid-state NMR

• liquids: liquid-state NMR

• gas

• DNA and proteins

• x-ray cristallisation

• RNA

• NMR-spectroscopy

• in an oven, silver atoms arereleased by eraporation and accelerated

• the beam is bundeld by an aperture befor being directed into the innomogenous magnetic field

• when the beam leaves the magnetic field, it hits a glass plate (detector) on which the silver atoms can settle

• the spread of electrons was different than expected

• it shows not 1 but 2-spots of electrons!

• spot 1 —> ß-state of high energy + 1/2 spin

• spot 2 —> alpha-state of low energy - 1/2 spin

• both distance d

  
  

  —> Zeeman-Effect

• adding a oscillating magnet

—> all alpha-state are converted into ß-states

• H, C, N, O, P, F

• Rule: Elements with an odd number in their molecular weight are NMR active

• for example: 1 H, 31 P, 19 F

  • Isotypes of common elements can be NMR active as well

  • f.e. 13 C as isotype of 12 C

• common elements in DNA are C, P, O, H, N

  • Proton-NMR-spectroscopy

  • Phosphor-NMR-spectroscops

• the value of an analyte on the NMR spectrum (=delta)

• is given in the unite ppm (=10^-6)

• the theoretical value can be taken from an tabel to compare to experimental values

—> the chemical shift can be changed by the enviorment!!!

• f.e. the dissolvent changes the chemical shift

• exampel: H2O dissolved 1. in DMSO and 2. in chloroform

• the neighbour of a proton changes its internal enviorment

• example: Methanol

• Ha,b,c have a different internal enviorment than Hd because C and O are not the same

  • the electronegativity matters

  • 1 signal for Ha,b,c [equivalent] and 1 signal for Hd [non-equivalent to the others]