Deuterated compound
Deuterated compounds are chemical compounds in which one or more hydrogen atoms (with the mass number 1) have been replaced by deuterium (with the mass number 2). These compounds are often used in nuclear magnetic resonance spectroscopy .
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- Heavy water (D 2 O)
- Deuterochloroform (CDCl 3 )
- Hexadeuterobenzene (C 6 D 6 or benzene-d 6 )
- Methanol-d 1 and methanol-d 4
- Hexadeuteroacetone (acetone-d 6 )
- DMSO-d 6
- DMF -d 7
- Dichloromethane -d 2 (CD 2 Cl 2 )
- Acetonitrile -d 3
- Acetic acid -d 4
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chemistry
In organic chemistry or organic analysis , partially deuterated molecules are used to elucidate reaction mechanisms . Different techniques are used:
- Infrared spectroscopy in order to be able to infer the RH or RD vibration bands of the molecule. Here, the approximate doubling of the mass of deuterium compared to hydrogen is used, whereby the following applies approximately:
- = Stretching vibration frequency (RX bond)
- In the NMR spectroscopy hochdeuterierte solvents are used, since the deuterium resonance in modern devices as so-called lock signal is used. This means that the device checks the stability of the magnetic field via the position of the resonance and corrects the measurement parameters. In 1 H-NMR spectroscopy, deuterated solvents have the advantage that practically no solvent signals can be seen in the spectrum (small traces of incompletely deuterated solvent can normally still be seen). In addition, acidic H atoms in the sample can be exchanged with deuterium oxide in a targeted manner in order to facilitate signal assignment.
- In mass spectrometry , the exchange of acidic protons can be used by increasing the molar mass - by one unit per acidic proton - in order to determine this in a targeted manner in structure elucidation and evidence.
- In the elucidation of reaction mechanisms , the deuteration of compounds is used to determine the order of a reaction - by using the kinetic isotope effect .
- In chromatography , more precisely in GC-MS and LC-MS , deuterated reference substances are used as internal standards because they behave analytically similar to the substances to be examined (similar behavior during sample preparation, similar retention times), but usually not in the Samples occur. Due to the slightly different molar masses, they can easily be distinguished from the undeuterated compounds using a mass-selective detector . Examples of deuterated internal standards for chromatography are atrazine-d5 ( CAS 163165-75-1) or anthracene-d10 ( CAS 719-06-8).
Biology, pharmacy, environmental science
Targeted deuterated agents, e.g. B. drugs , are used to study the metabolism of such substances.
Polymer physics
With the help of neutron scattering , the structure of a polymer is made “visible”. Here one makes use of the enlargement of the scattering cross-section for neutron scattering. The scattering cross-section of deuterium (σ = 5.59 · 10 −24 cm 2 ) is much larger than that of hydrogen (σ = 1.76 · 10 −24 cm 2 ).
