Chapter 13 - Chapter 13. NMR"for his development of nuclear magne<c resonance spectroscopy for determining the three

Info iconThis preview shows page 1. Sign up to view the full content.

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

Unformatted text preview: Chapter 13. NMR "for his development of nuclear magne<c resonance spectroscopy for determining the three ­dimensional structure of biological macromolecules in solu<on" Kurt Wüthrich Switzerland Eidgenössische Technische Hochschule (Swiss Federal Ins<tute of Technology) Zurich, Switzerland Nuclear magne<c resonance Chemical shiMs The posi<on of an absorp<on on the horizontal axis is called its chemical shiM. Reference: TMS Electron alignment by magne<c field Energy difference upon alignment Understanding chemical shiM Units of chemical shiMs: ppm Study Problem 13.2: An unknown compound with the molecular formula C5H11Br has an NMR spectrum consis<ng of two resonance: one at δ=1.02 (rela<ve integral 8378 units), and the other at δ=3.15 (rela<ve integral 1807 units). Propose a structure for this compound. n+1 spli^ng rule Mul<plica<ve spli^ng 1 ­bromo ­3 ­chloropropane NMR of alkenes Problem 13.24 Carbon NMR NMR spectra of alcohol NMR solvents: CCl4, CDCl3, CD2Cl2 Hydrogen ­bonding D2O shake (exchange) D2O shake subs<tutes a hydrogen by deuterium, elimina<ng its resonance form proton NMR and the spli^ng that the hydrogen causes. NMR Spectrometer Key Points •  NMR basic concept: nuclear magne<c resonance, opera<ng frequency, resonance absorp<on, chemical shiM; •  Physical basis: gyromagne<c ra<o, different energy of electrons with different spins; •  Physical basis of chemical shiMs and shielding; •  Effects of electronega<vity on proton chemical shiMs; •  Determina<on of unknown structures by NMR spectroscopy; •  Spin ­spin spli^ng; analysis of spli^ng; Informa<on about connec<vity; •  n+1 rule (excep<ons); •  Mul<plica<ve spli^ng; •  D2O shake; applica<on of simplifying NMR spectra of alcohols; •  NMR characteris<cs of alkenes, alkanes and cycloalkanes; •  Carbon NMR. ...
View Full Document

This note was uploaded on 08/24/2010 for the course CHEM 3351 at Colorado.

Ask a homework question - tutors are online