Larrousee’s Illustrated Dictionary of NMR Spectroscopy


Larrousee’s Illustrated Dictionary of NMR Spectroscopy

Nuclear magnetic resonance spectroscopy, more commonly known as NMR spectroscopy, is a powerful analytical technique used to study the structure and composition of molecules. NMR spectroscopy relies on the fact that the nuclei of certain atoms possess a property known as spin. When placed in a magnetic field, these nuclei will align themselves either with or against the field, depending on their spin. By measuring the amount of energy required to flip the nuclei from one alignment to another, scientists can obtain detailed information about the molecules in which they are contained.

NMR spectroscopy is a versatile tool that can be used to study a wide variety of molecules, including proteins, carbohydrates, and lipids. It is also a relatively non-invasive technique, making it ideal for studying biological samples. In recent years, advances in NMR spectroscopy have made it possible to obtain detailed three-dimensional images of proteins, providing valuable insights into their structure and function.

While NMR spectroscopy is a complex technique, it is possible to obtain useful information even if you are not a trained spectroscopist. This dictionary is designed to provide a basic introduction to the key concepts and terms used in NMR spectroscopy. With its clear explanations and illustrations, it is an essential resource for anyone working with or interested in this powerful analytical tool.

A

Absolute Configuration: The three-dimensional arrangement of the atoms in a molecule.

ACQ: See Acquisition.

Acquisition: The process of collecting NMR data. This data is then processed to yield the final NMR spectrum.

Alias: An error that can occur in NMR spectra due to the limited resolution of the instrument. This error can lead to the misidentification of peaks in the spectrum.

Aliphatic: A type of molecule that contains only carbon and hydrogen atoms.

Aromatic: A type of molecule that contains one or more benzene rings.

B

Benzene Ring: A ring of six carbon atoms that are each bonded to two hydrogen atoms. Benzene rings are a key component of many aromatic molecules.

C

Carbon-13 NMR: A type of NMR spectroscopy that uses carbon-13 atoms as the nuclei. Carbon-13 NMR is often used to study organic molecules.

Chemical Shift: The position of a peak in an NMR spectrum relative to a reference compound. The reference compound is typically chosen to be one with a known chemical shift.

D

Diamagnetic: A type of molecule that is not affected by a magnetic field.

E

Echo: A signal that is generated when the nuclei in a sample are subjected to a pulsed magnetic field. Echoes can provide information about the structure of a molecule.

F

FID: See Free Induction Decay.

Free Induction Decay: The signal that is generated when a sample of nuclei is placed in a magnetic field and then excited with a pulse of radiofrequency energy. The FID is then used to generate the final NMR spectrum.

G

Gain: The amount by which the amplitude of an NMR signal is increased.

H

Heteronuclear: A type of molecule that contains more than one type of nucleus. Heteronuclear NMR spectroscopy is used to study these molecules.

I

Inductive Effect: The influence that a substituent has on the chemical shift of a molecule. This effect is due to the inductive effect of the substituent.

J

J-Coupling: The coupling between the nuclear spins of different atoms in a molecule. J-coupling can provide information about the structure of a molecule.

K

Ketone: A type of molecule that contains a carbonyl group.

L

Lactone: A type of molecule that contains a lactone ring.

M

Magnetic Field: The force that is generated by a magnet. NMR spectroscopy relies on the fact that the nuclei of certain atoms are affected by magnetic fields.

Magnetic Resonance: The phenomenon that occurs when the nuclei of atoms are affected by a magnetic field. NMR spectroscopy relies on this phenomenon to obtain detailed information about molecules.

Magnetization: The state of a sample of nuclei in a magnetic field. The magnetization of a sample can be used to obtain information about the molecules in the sample.

Mass Spectrometry: A type of spectroscopy that uses the mass of a molecule to obtain information about its structure. Mass spectrometry is often used in conjunction with NMR spectroscopy.

N

NMR: See Nuclear Magnetic Resonance.

Nuclear Magnetic Resonance: The phenomenon that occurs when the nuclei of atoms are affected by a magnetic field. NMR spectroscopy relies on this phenomenon to obtain detailed information about molecules.

O

Organic: A type of molecule that contains carbon atoms.

P

Paramagnetic: A type of molecule that is affected by a magnetic field.

Proton NMR: A type of NMR spectroscopy that uses protons as the nuclei. Proton NMR is often used to study organic molecules.

Q

quadrupole moment: A property of a nucleus that determines how much it will interact with a magnetic field. The quadrupole moment can be used to obtain information about the structure of a molecule.

R

Relaxation: The process by which the magnetization of a sample of nuclei returns to its equilibrium state. Relaxation can be used to obtain information about the structure of a molecule.

S

Signal: The output of an NMR experiment that contains information about the molecules in the sample.

Solvent: The medium in which a sample is dissolved. The type of solvent used can have a significant impact on the NMR spectrum of a molecule.

Spin: A property of the nuclei of certain atoms that determines how they will interact with a magnetic field.

T

T1 Relaxation: The process by which the magnetization of a sample of nuclei returns to its equilibrium state. T1 relaxation can be used to obtain information about the structure of a molecule.

T2 Relaxation: The process by which the magnetization of a sample of nuclei returns to its equilibrium state. T2 relaxation can be used to obtain information about the structure of a molecule.

U

Unsaturated: A type of molecule that contains one or more double or triple bonds.

V

Van der Waals Forces: The attractive forces that exist between molecules. Van der Waals forces can have a significant impact on the structure of a molecule.

W

Water Peak: A peak that appears in the NMR spectrum of water. The water peak can be used to obtain information about the structure of a molecule.


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