Master by Reseach
School of Chemistry
Zhang, Qing Xiang, Preliminary ion mobility mass spectrometric studies on fullerenyl bisadducts, Master by Reseach thesis, School of Chemistry, University of Wollongong, 2009. http://ro.uow.edu.au/theses/3101
In this study, four selected regioisomeric tetraethyl bismethanofullerenyl tetracarboxylates (trans-4, e, cis-2 and cis-3 symmetry patterns) were prepared through the chemical methods reported in the literature with satisfactory yields and purities. They were subsequently analysed by ion mobility mass spectrometry (IMMS) to examine the potential of this method to resolve fullerenyl bisadduct regioisomers of the same molecular weights based on their different cross-sectional areas. This study was also of interest to see if these regioisomeric compounds would undergo a “walk-on-the-sphere” rearrangement under the reductive conditions of – ve ion mode ESIMS.
The tethered bisadducts (40), (41), (43), (44) and (46) were chemically prepared according to Nierengarten’s report giving the desired products with satisfactory yields and purities. Transesterification of these tethered bisadducts with distilled and dry methanol generated the non-tethered bisadducts (47) – (50).
The employment of IMMS in this study was to enable a comparison of the cross-sectional areas of the tethered and non-tethered fullerenyl bisadducts, providing some structural information that might be useful for further studies of fullerenyl derivatives of complicated structures in the future. The size of the cross-sectional area of a fullerenyl derivative was directly reflected by the length of the drift time required to travel through the drift tube of the spectrometer, in both the + ve and – ve ion modes. In the case of this study, all of the four non-tethered bisadducts (47) – (50) may have experienced an incomplete “walk-on-the-sphere” rearrangement under the reductive conditions of their – ve ion IMMS studies. Further improvements of experimental conditions might be necessary in order to enhance the occurrence of such rearrangements in future studies.
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