Lecture 23 - Diamagnetic Anisotropy and Spin-Spin Splitting

author: J. Michael McBride, Department of Chemistry, Yale University
recorded by: Yale University
published: Aug. 19, 2014,   recorded: April 2011,   views: 1460
released under terms of: Creative Commons Attribution No Derivatives (CC-BY-ND)
Categories

See Also:

Download Video - generic video source Download yalespan125bs2011_mcbride_lec23_01.mp4 (Video - generic video source 562.9 MB)

Download Video Download yalespan125bs2011_mcbride_lec23_01_640x360_h264.mp4 (Video 144.8 MB)


Help icon Streaming Video Help

Related Open Educational Resources

Related content

Report a problem or upload files

If you have found a problem with this lecture or would like to send us extra material, articles, exercises, etc., please use our ticket system to describe your request and upload the data.
Enter your e-mail into the 'Cc' field, and we will keep you updated with your request's status.
Lecture popularity: You need to login to cast your vote.
  Bibliography

Description

Through-space interaction between magnets of fixed strength and orientation averages to zero during random molecular tumbling, suggesting that the local field about a proton should be sensitive only to electrons that orbit about itself. The chemical shift can be sensitive to electrons orbiting elsewhere if the amount of orbiting varies with molecular orientation. This "diamagnetic anisotropy" is commonly used to rationalize the unusual chemical shifts of protons in acetylene and in aromatic and antiaromatic compounds. The other source of a proton's local field is nearby magnetic nuclei, which can be counted by the splitting multiplicity. Unlike chemical shift, which is measured in fractional units because it depends on the strength of the applied field, this spin-spin splitting (J), measured in Hz, is dependent only on molecular structure. J depends not on spatial proximity, but on orbital overlap, which, remarkably, is larger for anti- than for eclipsed conformations.

Link this page

Would you like to put a link to this lecture on your homepage?
Go ahead! Copy the HTML snippet !

Write your own review or comment:

make sure you have javascript enabled or clear this field: