Information that can be obtained from NMR Spectra
Information about the structure, conformation and dynamics of small and large molecules can be obtained in the solution and solid state. However, in view of the fact that adequate facilities for low field NMR exist in the country, the high resolution Facility will undertake only such problems, which cannot be solved at other Facilities. For an efficient use of the Facility it is advisable that the User bring a low field NMR spectrum on the same sample and concentration.
The high field (better sensitivity) along with signal averaging, should in principle give a signal for samples of low concentration if scanned for long duration. With the inherent limitations of the NMR spectrometer coupled with the high cost of spectrometer time particularly for sophisticated spectra, it is advantageous to work with maximum possible concentration of samples. For low molecular weight (MW < 250) compounds a minimum of 1-3 mg and for high molecular weight 2-5 mg of samples should be provided for proton spectra. For proton decoupled Carbon-13 spectra, 50-100 mg of sample will be required. For 13P spectra 5-20 mg of sample will be required. For solid state NMR sample requirement is ~ 100 mgs.
For ensuring magnetic field stability and adjusting field homogeneity, a deuterium lock channel is provided. Therefore, samples are to be dissolved in a deuterated solvent. Deuterated solvents like D2O, CDCl3, are provided by the Facility free of cost. However Users have to pay for expensive solvents such as CD3COCD3, DMSOd6, C6D6, etc.. The User should check the solubility of the sample in any of these solvents (of course, in undeuterated solvent) and suggest best solvent. For certain specialized experiments high isotopic enrichment or depletion in the solvent may be desirable. The Facility cannot provide such solvents and the Users should bring such solvents whenever necessary.
The usage charges for NMR at TCIS, Hyderabad is as follows:
|Spectrometer||Solid state(per sample/hour)||Solution state(per sample/hour)|