O2: 32 Structure determination Flashcards
1
Q
How can structures of new compounds be confirmed?
In general
A
By a range of analytical techniques, developed by scientists.
2
Q
What does NMR give information about?
A
The position of 13C or 1H atoms in a molecule.
3
Q
Between 13C NMR and 1H NMR, which one gives simpler spectra?
A
13C NMR
4
Q
What does chemical shift depend on?
A
The molecular environment.
5
Q
What do integrated spectra indicate?
A
The relative numbers of 1H atoms in different environments.
6
Q
How are 1H NMR spectra obtained?
What solvent is used to dissolve samples?
A
Using samples dissolved in CCl4.
7
Q
What is used as a standard in NMR?
A
Tetramethylsilane (TMS).
Si(CH3)4
8
Q
Why is tetramethylsilane a suitable substance to use as a standard?
A
- produces a single absorption peak
- peak is away from other absorption peaks
- inert
- non-toxic
- volatile, so easy to remove (low bp)
