The university is 30 years old. Discover its past and present. Help build its future.
14 February 2017
Find out about bachelor's degrees, postgraduate courses and all the educational courses offered by the UdG.
Teaching is concentrated in the faculties and schools, and the departments deal with research, which is also conducted by institutes and chairs, at the same time responsible for knowledge promotion.
The spectroscopy of nuclear magnetic resonance (RMN) it is one of the espectroscòpiques techniques more important for theelucidation of structures. Its application is relatively recent. In year 1945 two groups of physicists working independently (Purcell, Torrey and Pound at the University of Harward and Bloch, Hansen and Packard in that of Stanford) they observed for the first time the phenomenon of the RMN in solids and liquids. This phenomenon was used by the resolution of a chemical problem at first of the fifties. Since then, its importance has kept on growing, until in year 1991 the Nobel Prize of Chemistry was conceded to R.R. Ernst for its contribution to the development of the experimental techniques of RMN.
It is recommended to put deuterat between 10 and 15 mg of sample in 0.66 mL of solvent for putting the sample in the tubes of RMN.
In order to request the analysis of a sample for RMN, you have to get yourselves with the staff responsible for the team in touch.
You will need to give the toxicity and any storage precautions. Once the report has been delivered, if you do not collect the sample within one week, any remaining sample will be destroyed.
SampleXpress Lite:
The physical foundation of the spectroscopy of RMN is in the magnetic properties of the atomic core. The interaction of the magnetic moment of a core with an external magnetic field brings about a split of the energetic levels. Transitions can be generated among these different states and the absorption of energy can be detected and record like a spectral line, signal renown of resonance. In this way, spectres can be obtained from compounds that contain atoms the cores of which have magnetic moments different of zero. Among these they find themselves the 1H, 19F, 14N and 15N and others of interest in chemistry. The core of 12C, of great importance in organic chemistry, shows too atomic and even atomic numbers and, therefore, it does not show magnetic moment. Thus, the studies of RMN of C limit themselves to the isotope 13C, that it only shows a natural abundance of the 1,1%.
Of a spectre of RMN we can extract three basic data that have to be useful to us for being able to determine the structure in dissolution of our molecule:
They can also contain frequencies of a single core (homonuclears) or of different cores (heteronuclears). This type of experiments is important for the analysis of complex spectres with a great overlap of signals and allow the study of systems as complex as the natural products, biopolymers, proteins or nucleic acids.
The correlations between the chemical displacement or the spin-spin coupling and the structure of the compounds form the basis of the application of the RMN to the determination of unknown compounds structures. Thus, the chemical displacement allows to know the chemical environment in which a core is placed and the integration allows to extract conclusions related to the number from present cores. The spin-spin coupling allows to define the relative positions of the cores, given that the magnitude of the interaction spin-spin (constant of coupling, J) depends of the number and types of links that sort out the different cores.
Another application of the spectroscopy of RMN derives from the observation of the fact that the spectre of RMN of many compounds depends on the temperature. That is, the form of the signal of RMN depends on dynamic processes and on the speed in which these processes take place. Therefore, the spectroscopy of RMN can be used for the study of fast reversible reactions that cannot be followed with the classical kinetic methods.
Moreover, the spectroscopy of RMN is also useful for the study of reaction mechanisms in all the branches of the chemistry. In these experiments isotopes of the hydrogen are used, carbon or nitrogen (2H, 13C, 15N) for the follow-up of an atom in particular during the reaction of interest.
In organic and biochemical chemistry, the spectroscopy of RMN of 13C plays a fundamental role, although the 19F, 15N and 31P also give very valuable information. In inorganic chemistry, a great number of cores of interest can be used thanks to the fast development of the experimental techniques. Since almost all the elements of the periodic table contain a stable isotope with magnetic moment, the area of utilisation of the spectroscopy of RMN is very extensive, even though the abundance born in a lot of these isotopes is small.
Choose which types of cookies you accept which the University of Girona can store in your browser.
Those that are essential for enabling your connection. There is no option for disabling them, as they are necessary for the functioning of the website.
These enable your options to be remembered (for example language or region you are accessing from), to provide you with advanced services.
They provide statistical information and enable improved services. We use Google Analytics cookies which you can deactivate by installing this plugin.
To offer advertising contents relating to the interests of users, either directly, or through third parties (“adservers”). These must be activated if you wish to see the YouTube videos uploaded to the University of Girona’s website.
The University of Girona website uses its own and third-party cookies for technical and analytical purposes. To manage them use the manager. If you would like further information, please access our Cookies Policy.