Dave's+analysis+of+the+H-NMR+of+NADPH

NADPH

Figure 1-1: The HNMR spectrum of NADPH.

Figure 1-2: A triplet is observed from a range of 1.155 ppm to approximately 1.190 ppm. This triplet corresponds to an ethanol impurity in the HNMR spectrum of NADPH, which is known via comparison of [|ethanol’s] spectrum, as well as the quartet that is also present in this HNMR.

Figure 1-3: This quartet occurs at approximately 3.620 ppm to 3.675 ppm. A quartet is not known to occur anywhere on the NADPH molecule, no possible coupling can exhibit this feature because common quartet coupling groups such as a methyl group are not observed. This quartet corresponds to an ethanol impurity in the sample, which is also seen by the triplet in the alkyl region.

Figure 1-4: A multiplet is observed from the range of 4.020 ppm to approximately 4.060 ppm. This extensive coupling can be attributed to the protons located on the cyclic ether groups that are not only slightly deshielded by the mass of oxygen atoms, but exhibit such coupling due to chiral centers differentiating every CH2 group. Corresponding to this could be the proton linked to the attatchment of the far left cyclic ether with that of the multiple ring system, which would be expected to be a very deshielded doublet because its surrounded by both a Nitrogen and an Oxygen atom.



Figure 1-5: A large number of peaks are observed from the range of 4.140 ppm to approximately 4.225 ppm. This multiplet is difficult to analyze due to the extensive nature of the proton coupling, yet is most likely due to the coupling located on either of the cyclohexyl ring, as well as the contribution of chiral centers which effects the coupling constant of every CH2 molecule in NADPH.

Figure 1-6: This residual peak at 4.810 ppm corresponds to the HDO peak in the molecule, meaning that every acidic proton in the spectrum will not be seen in this HNMR as it is replaced by a deuterium molecule.

Figure 1-7: This doublet spanning from 6.195 ppm to 6.220 ppm corresponds to the protons linked onto the cyclohexadiene double bonds formed at the vinylic positions in the molecule. The other proton should clearly represent a triplet of doublet of doublets (12 peaks), yet is not observed in the spectrum most likely because it is grouped amongst a complex multiplet.

Figure 1-8: A broad peak is observed from 6.915 ppm to approximately 6.930 ppm. This peak could have some slight multiplicity occurring or could be the result of a very broad singlet, which makes the positioning of this proton signal difficult due to deshielding in the molecule. A small coupling constant is noticeable at the very top of the peak, indicating that this is more than likely a doublet.

Figure 1-9: This singlet occurs at approximately 8.225 ppm and corresponds to a proton that does not exhibit coupling on the aromatic ring.

Figure 1-10: This singlet occurs from approximately 8.460 ppm to 8.475 ppm in the spectrum and corresponds to a proton located on the aromatic ring. Its value is slightly shifted upfield due to it being directly surrounded by two nitrogen atoms. The smaller peak located at approximately 8.410 ppm could be a contaminant in the sample due to its size.


 * [looks good - ambitious choice JCB]**

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