Selective Bond Cleavage in Informational Poly(Alkoxyamine Phosphodiester)s

International audience; The collision-induced dissociation (CID) of sequence-defined poly(alkoxyamine phosphodiester)s was studied by electrospray ionization mass spectrometry. These informational polymers were synthesized using three different nitroxide building blocks, namely proxyl-, SG1-and TEMPO-derivatives. For a polymer containing TEMPO-and SG1based main chain alkoxyamines, it was found that both types of alkoxyamines break in CID tandem mass spectrometry (MS/MS). However, SG1-sites are preferentially cleaved and this predominance can be increased by reducing collision energy, even though selective bond fragmentation was not observed. On the other hand, for a polymer containing proxyl-and SG1alkoxyamines, selective bond cleavage was observed at all studied collision energies. The SG1alkoxyamines can be first cleaved in MS/MS conditions and secondly the proxyl-alkoxyamines in pseudo-MS 3 conditions. These results open up interesting new avenues for the design of readable, erasable or programmable informational polymers.