{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Ch_322a_9.015 - Proton Splittings Decoupling Strategies 13...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Proton Splittings: Decoupling Strategies 13 C- 13 C Coupling Spin-spin interaction between two 13 C is not generally observed because of the low natural abundance of this minor isotope (1.1%). It is very unlikely that two of these "nmr active" nuclei will be close enough in a structure to spin-spin couple. 13 C- 1 H Coupling Spin-spin interactions between 13 C and 1 H are observed and may complicate the cmr spectrum. Typical J values for 13 C- 1 H ! are 100-320 Hz . Long range splittings due to 13 C- 1 H " and even 13 C- 1 H # are also significant. CMR spectra often show complex and overlapping multiplets that may be difficult to interpret.
Background image of page 1

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

View Full Document Right Arrow Icon
Decoupling Spin-Spin Interactions by Double Resonance Unwanted splittings by 1 H are eliminated by decoupling the hydrogen nucleus using a technique called double resonance . The energy splittings for the spin states of two coupled nuclei A and B in the presence of B o are shown below. ! E s B o B A At a specific value of B o , the frequencies required for resonance are !
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}