CHEM 2211 1st Edition Lecture 13Outline of Last Lecture I. Powerpoint of 15 no notes Outline of Current Lecture I. Chapter 15 cont. Current LectureH- NMR splitting The signals in an H NMR spectrum can be split into different numbers of peaks Most common are - Singlets- Doublets- QuartetThis splitting is caused by protons bonded to adjacent carbons It is described by the N+1 rule. - N is the number of equivalent protons bonded to an adjacent carbon that are not equivalent to the proton producing signal. o Or in other words the number of hydrogens on an adjacent carbon that does not produce the same signal. - This number of hydrogens gets 1 added to it to show what the signal will produce. - If the equivalent proton signal is not next to an atom with hydrogens it will be a singlet Like: CH3CH3 C the 3 CH3 groups are attached to a C with no Hydrogens attached.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.CH3 this means the CH3 signal will not be split it will be a singlet The number of peaks in a signal is called the multiplicity of the signal. Splitting is always mutual if group A is split by group B. B also must be split by group A. this is known as coupled protons. Let’s look at an example: In this example there are 2 signals. The one at 2ppm is a doublet The one at approximately 6ppm is a quartet Using the N+1 rule we can see why. For the one at 2ppm. It is the CH3 signal because N is the number of adjacent Hydrogens which is 1 plus 1 is 2. 2 is doublet split. And CH3 signal is closer to 0 than the CH signal because is it more shielded. The CH signal at 6ppm is a quartet because N is the number of adjacent hydrogens 3 in this caseplus 1 is 4. Which is a
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