1 H NMR Interpretation Using the NMR Mosaic. NMR Spectra contain THREE Pieces of Information...

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1H NMR Interpretation Using the NMR Mosaic

NMR Spectra contain THREE Pieces of Information

• Chemical Shift– Information about functionality

• Integration– Number of hydrogen MAKING the peak

• Multiplicity (splitting)– Number of NEIGHBOR hydrogens

ALL THREE must be used to solve spectrum

12 11 10 9 8 7 6 5 4 3 2 1

3 0 0 M H z ¹H N M RIn C D C l3

A L L R IG H T S R E S E R V E D© S igm a-A ld rich C o .

Chemical Shifts

OH, NH

Alkene

Adjacent to Oxygen

Adjacent to Cl, Br, I

Adjacent to double bond

Alkane-likeAromatic

Aldehyde hydrogen

Carboxylic acid hydrogen

Integration

• Rise of integral line indicates relative number of hydrogens

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

2

2

3

Multiplicity

• See one more peak than neighbor hydrogens– 0 hydrogens gives singlet

– 1 hydrogen gives doublet

– 2 hydrogens gives triplet

– 3 hydrogens gives quartet

Steps for Solving 1H NMR Spectra1. Calculate integration for each peak

a. #H = peak integration x (total # H’s / total integration)b. Smallest peak is often 1Hc. Peaks ~1 are often 3H (methyl)

2. Determine number of adjacent hydrogens from splitting- Number of peaks = n+1, where n = number of adjacent

hydrogens- Attach appropriate static cling(s)

3. Determine presence of functional group(s)- Attach functional group static cling(s)- Choose functional group Mosaic piece(s)

Calculate # H’s for each peak

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

C3H7Cl

Calculate # H’s for each peak

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

C3H7Cl

2H 2H 3H

Make NMR Mosaic Pieces

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

C3H7Cl

2H 2H 3H

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

Make NMR Mosaic Pieces: C3H7Cl

H | ─C─ | H

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

H | ─C─ | H

CH2

Make NMR Mosaic Pieces: C3H7Cl

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

H | ─C─ | H

CH2 Fun

ct. G

rp.

Make NMR Mosaic Pieces: C3H7Cl

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

X-

H | ─C─ | H

CH2 Fun

ct. G

rp.

Make NMR Mosaic Pieces: C3H7Cl

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

X-

H | ─C─ | H

CH2 Fun

ct. G

rp.

Make NMR Mosaic Pieces: C3H7Cl

H | ─C─ | H

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

X-

H | ─C─ | H

CH2 Fun

ct. G

rp.

Make NMR Mosaic Pieces: C3H7Cl

H | ─C─ | H

CH3

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

H | ─C─ | H

CH2 Fun

ct.

Grp

.

X-

H | ─C─ | H

CH2

CH3

Make NMR Mosaic Pieces: C3H7Cl

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

H | ─C─ | H

CH2 Fun

ct.

Grp

.

X-

H | ─C─ | H

CH2

CH3

H |H─C─ | H

Make NMR Mosaic Pieces: C3H7Cl

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

H | ─C─ | H

CH2 Fun

ct.

Grp

.

X-

H | ─C─ | H

CH2

CH3

H |H─C─ | H

CH2

Make NMR Mosaic Pieces: C3H7Cl

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

H | ─C─ | H

CH2 Fun

ct.

Grp

.

X-

H | ─C─ | H

CH2

CH3

H |H─C─ | H

CH2

1-chloropropane

Make NMR Mosaic Pieces: C3H7Cl

C6H12O2

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

C6H12O2

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

H | ─C─ | H

Funct. G

rp.

CH

─ O ─

C6H12O2

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

H |H─C─ | H

Fun

ct. G

rp.

H | ─C─ | H

Funct. G

rp.

CH

─ O ─

O || ─ C ─

C6H12O2

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

H |H─C─ | H

Fun

ct. G

rp.

H | ─C─ | H

Funct. G

rp.

CH

H | ─C─ |

CH

3

CH2

CH3

─ O ─

O || ─ C ─

C6H12O2

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

H |H─C─ | H

Fun

ct. G

rp. H

|H─C─ | H

CH

(2 of these)

H | ─C─ | H

Funct. G

rp.

CH

H | ─C─ |

CH

3

CH2

CH3

─ O ─

O || ─ C ─

C6H12O2: Isobutyl acetate

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

─ O ─

O || ─ C ─

H |H─C─ | H

Fun

ct. G

rp.

H

|

H─

C─

|

H

CH

H | ─C─ | H

Funct. G

rp.

CH H | ─C─ |

CH

3

CH2

CH3

H |H─C─ | H

CH

C7H14O2

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

C7H14O2

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1.00

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

─ O ─

H | ─C─ |

Fun

ct. G

rp.

CH

3CH3

C7H14O2

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1.00

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

─ O ─

H | ─C─ |

Fun

ct. G

rp.

CH

3CH3

H | ─C─ | H

CH2 Fun

ct. G

rp.

O || ─ C ─

C7H14O2

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1.00

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

─ O ─

H | ─C─ |

Fun

ct. G

rp.

CH

3CH3

H | ─C─ | H

CH2 Fun

ct. G

rp.

O || ─ C ─

H | ─C─ | H

CH2

CH3

C7H14O2

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1.00

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

─ O ─

H | ─C─ |

Fun

ct. G

rp.

CH

3CH3

H | ─C─ | H

CH2 Fun

ct. G

rp.

O || ─ C ─

H | ─C─ | H

CH2

CH3

H |H─C─ | H

CH

(2 of these)

C7H14O2

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1.00

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

─ O ─

H | ─C─ |

Fun

ct. G

rp.

CH

3CH3

H | ─C─ | H

CH2 Fun

ct. G

rp.

O || ─ C ─

H | ─C─ | H

CH2

CH3

H |H─C─ | H

CH

(2 of these)

H |H─C─ | H

CH2

C7H14O2: Isopropyl butyrate

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

H | ─C─ | H

CH2

CH3

H | ─C─ | H

CH2 Fun

ct. G

rp.

H |H─C─ | H

CH

H |H

─C

─ | H

CH

H |H─C─ | H

CH2

─ O ─

O || ─ C ─

H | ─C─ |

Funct. G

rp.C

H3 CH3

C6H12O2Cl

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

C6H12O2Cl

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1.00

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

─ O ─

H | ─C─ | H

Funct. G

rp.

CH3

C6H12O2Cl

0.00

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1.00

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

─ O ─

H | ─C─ | H

Funct. G

rp.

CH3

H | ─C─ | H

CH2 Fun

ct. G

rp.

X-

C6H12O2Cl

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1.00

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

─ O ─

H | ─C─ | H

Funct. G

rp.

CH3

H | ─C─ | H

CH2 Fun

ct. G

rp.

X-

H | ─C─ | H

CH2 Fun

ct. G

rp.

C6H12O2Cl

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0.75

1.00

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

─ O ─

H | ─C─ | H

Funct. G

rp.

CH3

H | ─C─ | H

CH2 Fun

ct. G

rp.

X-

H | ─C─ | H

CH2 Fun

ct. G

rp.

H | ─C─ | H

CH2

CH2

C6H12O2Cl

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1.00

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

─ O ─

H | ─C─ | H

Funct. G

rp.

CH3

H | ─C─ | H

CH2 Fun

ct. G

rp.

X-

H | ─C─ | H

CH2 Fun

ct. G

rp.

H | ─C─ | H

CH2

CH2

H |H─C─ | H

CH2

C6H12O2Cl: Ethyl 4-chlorobutyrate

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1.00

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

─ O ─

O || ─ C ─ H

| ─C─ | H

Fun

ct. G

rp.

CH3

H |H─C─ | H

CH2

H | ─C─ | H

CH2 Fun

ct. G

rp.

X-

H | ─C─ | H

CH2

CH2

H | ─C─ | H

CH2Funct. G

rp.

NMR Mosaic Simplifies Interpretation of Complex Multiplets

• Adjoining pieces specify connectivity

• Interpretation is no longer “impossible”

Example: C4H9Cl

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

Example: C4H9Cl

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1.00

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

X- H | ─C─ |

Fun

ct. G

rp.

CH

3CH2

Example: C4H9Cl

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1.00

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

X- H | ─C─ |

Fun

ct. G

rp.

CH

3CH2

H | ─C─ | H

Undetermined

Splitting

Example: C4H9Cl

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300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

X- H | ─C─ |

Fun

ct. G

rp.

CH

3CH2

H | ─C─ | H

Undetermined

Splitting

H |H─C─ | H

CH

Example: C4H9Cl

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1.00

5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5

300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

X- H | ─C─ |

Fun

ct. G

rp.

CH

3CH2

H | ─C─ | H

Undetermined

Splitting

H |H─C─ | H

CH

H |H─C─ | H

CH2

Example: C4H9Cl

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0.25

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0.75

1.00

5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5

300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

X-

H | ─C─ |

Fun

ct. G

rp.

CH

3CH2

H | ─C─ | H

Undetermined

Splitting

H

|

H─

C─

|

H

CH

H |H─C─ | H

CH2

Example: C4H9Cl

0.00

0.25

0.50

0.75

1.00

5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5

300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

X-

H | ─C─ |

Fun

ct. G

rp.

CH

3CH2

H

|

H─

C─

|

H

CH

H |H─C─ | H

CH2 H | ─C─ | H

CH

CH3

2-chlorobutane

NMR Mosaic Helps Students Catch Mistakes

• Mosaic pieces no longer match

• Focus students on incorrectly interpreted peaks

Example: C3H7Cl

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0.7

0.8

0.9

1.0

1.1

1.2

3.5 3.0 2.5 2.0 1.5 1.0

300 MHz ¹H NMRIn CD Cl3

A LL RIG H TS RESERV ED© S igm a-A ldrich Co.

H|

H─C─|H

CH2

H|

H─C─|H

H|

H─C─|H

CH2H|

─C─|H

CH3

CH3

H|

─C─|H

CH3

CH3

H|

─C─|H

CH2 Func

t. G

rp.H

|─C─

|H

CH2 Func

t. G

rp.H

|─C─

|H

CH2 Func

t. G

rp.H

|─C─

|H

CH2 Func

t. G

rp.

Incorrect piece as an example

C3H7Cl

X-

Example: C3H7Cl

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0.7

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0.9

1.0

1.1

1.2

3.5 3.0 2.5 2.0 1.5 1.0

300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

H |H─C─ | H

CH2

H | ─C─ | H

CH3

CH3

H | ─C─ | H

CH2 Fun

ct.

Grp

.

X-Incorrect Match ↑

Example: C3H7Cl

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

3.5 3.0 2.5 2.0 1.5 1.0

300 MHz ¹H NMRIn CDCl3

ALL RIGHTS RESERVED© Sigma-Aldrich Co.

H |H─C─ | H

CH2 H | ─C─ | H

CH2 Fun

ct.

Grp

.

X-Corrected Piece

Matches

H | ─C─ | H

CH2

CH3

Steps for Solving 1H NMR Spectra1. Calculate integration for each peak

2. For each peak:•Choose correct base Mosaic piece based on integration

- Determine number of adjacent hydrogens from splitting and add static cling tab(s) to base piece

- Determine presence of functional group(s) - Add functional group static cling(s) - Choose appropriate functional group Mosaic piece(s)

3. Put Mosaic pieces together, making sure all colors match and all functional group chemical shifts match.