Stacking Interactions Of NMR) Spectroscopy Lab Report

1614 Words 7 Pages
Review of Stacking Interactions of Nucleobases: NMR Investigations by H. Sapper and W. Lohmann
Nuclear magnetic resonance (NMR) spectroscopy is often a very useful tool to identify organic molecules based on the atomic nuclei interactions with their environment. Recent advances have made use of the technology in protein, nucleic acid, and complex natural products structure identification. [1, 2, 3] Its origins lie in the works of Felix Bloch and Edward Purcell, who used the discoveries of Isidor Rabi’s extension on Stern-Gerlach experiment, and were awarded the Nobel Prize in 1952 for their use of NMR on solids and liquids. Packard notably observes this phenomena of nuclear resonance when a magnetic field was applied to an organic
…show more content…
[5] The energy difference between these two states can be calculated knowing the strength of the applied external magnetic field, the magnetic momentum of the element’s nuclei, and the spin.[5] This relationship is represented by this equation: ∆E=uB/I , where I is the spin and u is the magnetic momentum. ∆E equals hν when the frequency of the RF equals a particular frequency called the Larmor frequency, a frequency that precesses the magnetic field of the nuclei with the external field.[5] The spin of the nuclei can be put in resonance form if the RF matches the energy difference induced by an external magnetic field at the Larmor frequency. [5] An emission of energy occurs from spin relaxation when the nuclei is in resonance. [5] The absorption of RF required for the spin resonance is used for the ppm, the relative parts per million RF needed to induce the resonance when compared to a known standard. [5] Its peak size is concentration dependent and noted by the actual energy difference of the spin resonance signal …show more content…
Nowadays, the improved technologies enable researchers to employ NMRs with varying energy levels (20-800MHz) due to refined methods of construction and improved magnetic field strengths that can be applied to a NMR sample. Furthermore, NMR techniques have become so far advanced to where it can identify technically complex structural components by way of NOESY, HMQC, and HMBC to determine carbon-hydrogen interactions of a molecule, carbon-hydrogen interactions even multiple bonds away, and more. The development of these innovative techniques expand the tools that chemists have to characterize complex organic molecules, purity determination of a sample, and

Related Documents