Wednesday, February 16, 2011

Magnetic Circular Dichroism (MCD)

Ok, so this week in bio inorganic, I was assigned Magnetic Circular Dichroism to research and give a short synopsis of in class. MCD "measures the difference in electronic absorption of left and right circularly polarized light in a longitudinal magnetic field." What I understood this to mean was that a sample was placed in a magnetic field and then hit with circularly polarized light and then I got lost. I'm not exactly sure what happens when the light hits the sample and what exactly the detectors pick up, so any info on that would be greatly appreciated. I did however learn that MCD is very useful in determining the metal center oxidation state and spin state in a complex ion. Also, MCD gives electronic excited state properties and assignments and ground state magnetic properties (g-values, spin state, zero-field splittings, and magnetic couplings). Some of the limitations of MCD are that detailed electronic assignments are difficult for low-symmetry metal centers, or that it is not useful for investigating non-chromophoric (without color) metal centers. That was kind of the quick intro to MCD, so some parts may be confusing. Feel free to leave questions or info to help clarify my confusion. Thanks

-The High School Chemist
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4 comments:

  1. Dr. MFebruary 20, 2011 at 10:34 AM

    Don,

    You need to cite your sources, and maybe when you go back over them you will discover you'll understand it a little better.
    I would suggest you check out Nicolai Lehnert's group here:
    http://www.umich.edu/~lehnert/MCD.html

    :)

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  2. Don FlowersFebruary 20, 2011 at 11:22 AM

    source: http://www.uga.edu/cms/Biophy.html

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  3. MeganFebruary 20, 2011 at 5:09 PM

    When defining what MCD is I think you kind of need to know what circularly polarized is to really understands what happens. I think maybe what the definition means is it is kind of like wrapping a circular dichrometer in the electromagnet since these are a type of magnet whose magnetic field is produced in the flow of the electric current. I think the detectors help pick up the magnetic field which correlates to the superconducting magnet. r

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  4. AnonymousFebruary 27, 2011 at 2:39 PM

    This technique seems to be very complicated and I'm sorry but I didn't find any useful information to answer your questions. I did find that MCD can also be used in studying metalloproteins in biological systems as the presence of the degenerate energy levels creates strong signals. This indicates that maybe degeneracy has something to do with making the technique more applicable. It was a very good post and I learnt a lot :)

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