Depending on the solubility, all compounds were characterized via 1 H and 13 C NMR spectroscopy. Additionally, elemental analysis (CHN-EA) was performed, confirming the expected composition. For the less stable compounds 8 and 9 deviations of ~2 % can be seen for the C and N content, which can be attributed to self-decomposition as well as decomposition upon air and moisture contact, as a short exposure to the ambient is inevitable during sample submission.