Proton nmr and 13-C nmr

Question

oh ma GAWD could someone PLLEEEEAAAASSSE give me an explanation of NMR. Like totally put it in the SIMPLEST TERMS POSSIBLE - or send me to a website that will explain it for me and give me a really good ANALOGY to help me to understand it.

THANKS A BUNCH!!!

Answer 1

proton nmr is nuclear magnetic resonance - a technique for determing the chemical structure of an unknown.  It occurs when protons (hydrogen) are in a strong magnetic field (in the instrument.)  This causes the proton to spin at a particular frequency and the proton releases energy which gives information about its chemical environment.  As the magnetic field is shifted, the proton gives off differerent types of information in different directions.  

The more that a proton is "shielded" from the magnetic field (meaning the less direct contact it has with the field due to the presence of other atoms or functional groups where electrons withdraw density) the higher the frequency which it resonates.  

This information is processed by a computer and presented to you in a diagram which shows the chemical shift and coupling.  The chemical shift shows peaks on a diagram where a functional group resonates at a particular frequency.  The resonance is shown at certain frequencies on the diagram, certain patterns are known to be certain functional groups.  If you see a certain pattern then you know that a particular functional group is in the compound (for example, a CH3 or a hydoxyl group.)  Coupling gives you other information which helps you determine how the functional groups may be arranged.

C-13 NMR is analogous to proton NMR except that in C-13 NMR, carbon 13 resonates instead of protons and hence it gives you information about carbon groups in a compound.

An analogy? Um, this is a very rough analogy but say you are throwing things such as frisbys and rocks and such and each one tears apart into pieces when you throw it and everything falls apart the same way every time you throw it.  And each piece always lands in the same spot depending on what it is.  And you are throwing things blindfolded and not knowing what you are throwing.  But you can tell what you have thrown when you go out and look at what fell where.  When you see that some unidentifable piece of what was something has landed in a location in particular, then you know what it is because that object always lands that way.  Also, the way that the objects are pieced together is sort of identifiable based on how they land, too.

EDIT: also I didn't really know what you meant by "simplest terms" because one person's idea of simple is maybe complicated to someone else and vice versa.  In the future when you ask questions you might want to state what your idea of simple is: for example if you are a freshman nursing student or a senior college student, etc.