Lesson 1
Averaging and the NMR Time Scale 1
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Prof. McBride, J. Michael, CHEM 125b, Freshman Organic Chemistry II, Spring 2011, YALE Open Courses: Yale University, Chemistry (Accessed 16/09/2014), http://oyc.yale.edu/chemistry/chem-125b/lecture-24 License: Creative Commons BY-NC-SA "Higher-order effects" that give complex multiplets for nuclei with similar chemical shifts can be understood in terms of the mixing of wave functions of similar energy. Since the spectroscopic time scale depends on frequency differences, averaging is easier in NMR than in IR. A typical problem involves predicting the NMR spectrum of a compound with diastereotopic groups. In proton decoupling radio frequency irradiation of a particular proton can make it cease to split the NMR signals from nearby protons.

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