Nmr Spec Flashcards

1
Q

What is nmr used for

A

Used to determine the structures of unknown organic substances

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2
Q

Why is nmr so good

A

Easy to obtain a sample
Only small amount of sample needed
It is non destructive

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3
Q

Why is c13 used

A

Has spin and is significant enough to obtain a spectrum

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4
Q

Things you need to be able to interpret from a c13 spectrum

A

Number of peaks tells you number of carbon environments
Location of peaks tells you about the type of carbon environments

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5
Q

What does symmetry show

A

Same environments

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6
Q

Tms

A

Tetra methyl silane
Used as a reference standard for chemical shifts

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7
Q

Why is tms used as a standard

A

Generates 1 sharp peak (as all c are equivalent)
Unreactive so won’t affect sample being dissolved

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8
Q

What u need to be able to infer from h nmr spectrum

A

Number of peaks tells u number of environments
Location of peaks shows u type of proton environment
Area under each peak tells u number of protons in each environment
Splitting shows number of protons in neighbouring carbon

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9
Q

Spin rule

A

N+1
N is number of hydrogens on neighbouring carbon

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10
Q

What does o- h always split to

A

Singlet

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11
Q

Solvents

A

Has to be hydrogen free environment so doesn’t produce any peaks
So solvents using deuterium are used

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12
Q

For polar samples

A

Deuterated trichloromethane - CDCl3

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13
Q

Non polar samples

A

Deuterated benzene
C6D6

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