IMG_0002_NEW_0007 - of doublets(4 peaks and is worth...

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Splittins Diaerams In more complex situations, where a proton is coupled to more than one set of equivalent protons, the splitting for the proton of interest can be determined by following a splitting diagram. Consider 2-methyl- B H-p-C-C-H D 4-ethylhexane, there is a plane of symmetf i;;iir I I I ^ molecule, therefore there will be six sets of signals for A cH3 H cH2-cH3 the six chemically inequivalent protons. c E F Methyl (A) (intensity 6 protons) a doublet (6:0.8 ppm) Methine (B) (intensity I proton) will be 'split' into N+l : 6+l : 7 signals (a septet) by the methyl (A) and N+1 : 2+l :3 signals (a triplet) by the methylene (C). The resulting signal is a septet of triplets (or triplet of septets), which has 3 x j : 2l peaks! Needless to say it would appear as a multiplet (m) (6 : 1.8 ppm) Methylene (C) (intensity 2 protons) will be split into a doublet by methine (A) and a doublet by methine (D). The resulting signal is known as a doublet
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Unformatted text preview: of doublets (4 peaks) and is worth drawing out (see below) (6 : 1.5 ppm) Methine (D) (intensity I proton) a triplet of quintets (a multiplet) (6: 1.8 ppm) Methylene (E) (intensity 4 protons) a doublet of quartets (see below) (6 : 1.5 ppm) Methyl (F) (intensiQ 6 protons) will be a triplet (6 : 0.8 ppm) Note: for the following splitting trees the coupling constants (.1) ene made up to demonstrate a point - you do not need to know how to determine coupling constants. YOU DO NEED TO KNOW that if two sets of protons'couple'they will share an identical coupling constant. HE coupling constant with methylene E (12 Hz) coupling constant with methylene C(10 Hz) SOLViNG STRUCTURES - a useful formula *degrees ofunsaturation (double bonds and rings count as 1, triple bond counts as 2) degrees ofunsaturation : [2 x (# ofcarbon's) + 2 - (# ofhydrogen's) - (# halides)]+2 CEF AcH" H cH"-cH" l"tr I...
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This note was uploaded on 12/27/2011 for the course CHEM 281 taught by Professor Williams during the Fall '11 term at Simon Fraser.

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