Advanced Organic Chemistry: PART 15.3.2
USES of 1H
Chemistry Advanced Level Pre-University Chemistry Revision Study Notes for UK IB
KS5 A/AS GCE advanced A level organic chemistry students US K12 grade 11 grade 12 organic chemistry
of analysis and molecular structure determination
All my advanced A level organic chemistry notes
mobile phone or ipad etc. in 'landscape' mode
This is a BIG
website, you need to take time to explore it [SEARCH
The theory of H-1 NMR spectroscopy and
spectrometer - low and high resolution spectra
H-1 (proton) NMR spectra of organic compounds
Some simple NMR-IR
problem solving questions
15.3.2 The uses and
applications of 1H (proton) NMR Spectroscopy
Sub-index for this page
Determination of molecular structure
imaging (MRI scanning)
kinetics - experimental studies of the speed of a chemical
You can match 1H NMR resonance signals
from an 'unknown' substance with a database of NMR spectra of
known well characterised compounds.
A computing data base can match many
signals (chemical shift, δ in ppm) to suggest possible
structures, ideally a unique 'fingerprint' NMR signal.
TOP OF PAGE
(b) Determination of
1H NMR spectroscopy is a very powerful
technique for the structural determination of molecules.
From the different chemical shifts you can
build up a picture of parts of a molecule's structure.
NMR spectroscopy is so accurate that the
structure of quite complex organic molecules can be worked out
when combined with other data such as molecular mass and % C, H
and O etc.
In a sense you are working backwards
from the point of view of interpreting high resolution 1H NMR
spectra explained in ...
The theory of H-1 NMR spectroscopy
- interpreting high resolution spectra
NMR analysis can used in many situations
including identifying molecules from natural materials e.g.
molecules in a plant fragrance, molecules involved in some
It is a non-destructive method of
investigating molecular structure, which is a particularly
useful for complex biological molecules e.g. nucleic acids,
including RNA and DNA, or proteins, can be studied using nuclear
magnetic resonance for weeks or months before using destructive
TOP OF PAGE
Magnetic resonance imaging (MRI scanning)
An important scanning technique in
Collating the 1H NMR resonance signals
from sections of the human body is an important diagnostic tool
e.g. for medical problems associated with soft tissue and
collagen in bones.
An extremely powerful magnet is used to
generate a very strong magnetic field and the patient lies in
between the poles of this magnet and is subjected to pulses of
radio waves of around 40 MHz.
The hydrogen nuclei will re-emit the
absorbed the NMR frequencies.
The hydrogen nuclei in the soft tissue
have a different chemical shift to those in harder tissue,
giving contrasting contours of different emissions and a
computer can generate pictures of 'slices' of the parts of the
body being investigated.
Potential or actual problems can be
detected and diagnosed and the usually patient suffers no ill
effects from the radio waves and is a safe non-invasive medical
MRI scanning also has the advantage of
generating images of the body which CT scans, ultrasound and
An MRI scanner
scan</a> via Shutterstock)
credit: Courtesy FONAR Corporation)
An MRI scan can reveals the gross
anatomical structure of the human brain.
The brain, spinal cord and
nerves, as well as muscles, ligaments, and tendons are seen much
more clearly with MRI than with regular x-rays and CT and for
this reason MRI is often used to image knee and shoulder
A special kind of MRI scanning
is functional Magnetic Resonance Imaging (fMRI.) in which brain
structures can be observed and determine which areas of the
brain “activate” (consume more oxygen) during various cognitive
tasks. It is used to advance the understanding of brain function
and organization and offers an insight into assessing
neurological status and neurosurgical risk.
Because of the strong magnetic fields involved you have to be
care if any magnetic object is associated with the patient e.g.
People with implants, particularly those containing iron
e.g. pacemakers, vagus nerve stimulators, implantable
cardioverter- defibrillators, loop recorders, insulin pumps,
cochlear implants, deep brain stimulators, and capsules from
capsule endoscopy - non of these should not enter an MRI
TOP OF PAGE
Chemical kinetics - experimental studies of the speed of a chemical
If the reaction involves a change in
functional group, both involving a proton, you can follow the
change in intensity of chemical shifts that are specific to each
of the functional groups.
You can also following changes in
conformation, that is changes in the 3D orientation of a
key words and phrases: What can you
use NMR for? What is MRI How does MRI work? How are molecules
identified with 1H NMR? How is 1H NMR used to investigate molecular
TOP OF PAGE
All Advanced Organic
|Website content © Dr
Phil Brown 2000+. All copyrights reserved on revision notes, images,
quizzes, worksheets etc. Copying of website material is NOT
permitted. Exam revision summaries & references to science course specifications