13.7 Spin-Spin Splitting in NMR Spectroscopy

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Part 13; Spectroscopy. Examination of 1H-NMR SpectrumSpin-twist Splitting (n 1) ruleJ ValuesComplex splittingAnalysis of 13-C NMR Spectrum. 1H-NMR of 1,1,2-tribromoethane. Twist Spin Splitting. Coupling (collaboration) of nonequivalent, vicinal protons(n 1) Rule; If a 1H core has n nonequivalent, vicinal neighbors, its NMR sign will part into (n 1) crests.

Presentation Transcript

Slide 1

13.7 Spin-Spin Splitting in NMR Spectroscopy not all pinnacles are singlets signs can be part by coupling of atomic twists

Slide 2

Chapter 13; Spectroscopy Analysis of 1 H-NMR Spectrum Spin-turn Splitting (n+1) govern J Values Complex part Analysis of 13 - C NMR Spectrum

Slide 3

1 H-NMR of 1,1,2-tribromoethane

Slide 4

H C Spin-Spin Splitting Coupling (association) of nonequivalent, vicinal protons (n+1) Rule; If a 1 H core has n nonequivalent, vicinal neighbors, its NMR flag will part into (n+1) crests protons isolated by three bonds (vicinal relationship)

Slide 5

10.0 9.0 8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0 Cl 2 C H C H 3 Figure 13.12 (page 536) 4 lines; quartet 2 lines; doublet coupled protons are vicinal (three-bond coupling) C H parts C H 3 into a doublet C H 3 parts C H into a quartet C H 3 C H Chemical move (  , ppm)

Slide 6

H Cl H C H Cl this line compares to particles in which the atomic turn of the proton at C-1 fortifies the connected field this line compares to atoms in which the atomic turn of the proton at C-1 restricts the connected field Why do the methyl protons of 1,1-dichloroethane show up as a doublet? "true" concoction move of methyl protons (no coupling)

Slide 7

H Cl H C H Cl Why does the methine proton of 1,1-dichloroethane show up as a quartet? There are eight mixes of atomic twists for the three methyl protons. These 8 mixes split the flag into a 1:3:3:1 quartet.

Slide 8

Number of equivalent Appearance Intensities of lines protons to which H of multiplet in multiplet is coupled 1 Doublet 1:1 2 Triplet 1:2:1 3 Quartet 1:3:3:1 4 Pentet 1:4:6:4:1 5 Sextet 1:5:10:10:5:1 6 Septet 1:6:15:20:15:6:1 Splitting Patterns of Common Multiplets

Slide 9

10.0 9.0 8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0 BrC H 2 C H 3 The Ethyl Group 4 lines; quartet 3 lines; triplet C H 3 C H 2 Chemical move (  , ppm)

Slide 10

10.0 9.0 8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0 BrC H (C H 3 ) 2 IsoPropyl Group 2 lines; doublet 7 lines; septet C H 3 C H Chemical move (  , ppm)

Slide 13

1 H-NMR Spectrum

Slide 14

1 H-NMR Spectrum

Slide 15

1 H-NMR Spectrum

Slide 16

1 H-NMR Spectrum

Slide 17

Complex Splitting Patterns Multiplet of Multiplets Coupling Constant; J; Describes the separation in partition of tops in a multiplet. J abdominal muscle is dependably the same

Slide 18

Spin-turn part design for..

Slide 19

Spin-turn part design for..

Slide 20

H O 2 N 16 Hz m-Nitrostyrene; The H a flag shows up as a doublet of doublets. a J air conditioning = 16 Hz c b J air conditioning = 12 Hz 12 Hz 12 Hz

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