What's the purpose of tetramethylsilane in NMR? (1 Viewer)

[SummarisingHSC]

Lowkey get that it's a standard so maybe used for calibration purposes or similar but not too sure any clarification appreciated

 

[axolotl!]

As you have said, tetramethylsilane (TMS) is used for the sake of acting as a reference point for the chemical shifts of different peaks. Some reasons why it, specifically, is used for NMR are:

• Relatively inert - will not easily react with the organic molecule being analysed.
• Low boiling point - it can be easily removed once used.
• Gives a sharp signal in both H-1 and C-13 spectra as it onl;y has one type of hydrogen and carbon environment.
• It has an unusual H and C chemical environment which means its signal occurs outside the normal range observed for organic compounds so the reference signal is less likely to overlap a signal from the substance examined.
• The chemical shift of TMS is not substantially affected by complexation or solvent effects because the molecule does not contain any polar groups.

 

[SummarisingHSC]

As you have said, tetramethylsilane (TMS) is used for the sake of acting as a reference point for the chemical shifts of different peaks. Some reasons why it, specifically, is used for NMR are:

• Relatively inert - will not easily react with the organic molecule being analysed.
• Low boiling point - it can be easily removed once used.
• Gives a sharp signal in both H-1 and C-13 spectra as it onl;y has one type of hydrogen and carbon environment.
• It has an unusual H and C chemical environment which means its signal occurs outside the normal range observed for organic compounds so the reference signal is less likely to overlap a signal from the substance examined.
• The chemical shift of TMS is not substantially affected by complexation or solvent effects because the molecule does not contain any polar groups.

ah fair thanks for the clarification