Effects of polymorphic differences for sulfanilamide, as seen through 13C and 15N solid-state NMR, together with shielding calculations |
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Authors: | Portieri Alessia Harris Robin K Fletton Richard A Lancaster Robert W Threlfall Terence L |
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Institution: | Chemistry Department, Durham University, South Road, Durham DH1 4LE, UK. |
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Abstract: | We recorded both carbon-13 and nitrogen-15 NMR spectra of the three solid forms of sulfanilamide most commonly known. This study led to an interpretation of the solid-state effects seen in cross-polarization magic angle spinning spectra. Relaxation times for the different forms were measured. These show different behaviour for the three forms, arising from mobility variations. To obtain information on local environments, static spectra and spinning sideband manifolds were recorded and analysed for the 15N resonances, using isotopically enriched samples. Shielding asymmetries and anisotropies for the two nitrogen nuclei were obtained, showing very different behaviour for the two sites. Shielding calculations were carried out for both 13C and 15N nuclei, and the results are discussed in relation to the experimental values. |
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Keywords: | NMR CP/MAS NMR 13C NMR 15N NMR polymorphs sulfanilamide shielding computations hydrogen bonding relaxation |
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