Analysis by 1 H, C and 2D NMR spectra reveals the formation of terpolymers comprising carbonate, ester and thioester links, as exemplified in Figure . Following the polymerisation by H NMR analysis of aliquots removed at regular time intervals indeed reveals continuous PTA consumption and uniform generation of all esters, carbonate and thioester links, substantiating random terpolymer formation. Finally, IR spectroscopy of the isolated polymers further supports the presence of carbonate and ester (ṽ ≈ 1734.0 cm -1 ) in addition to thioester (ṽ ≈ 1676.0 cm -1 ) links, and in all cases, no homopolymer links could be observed. The precise ratio of ester:carbonate:thioester links depends on both the alkali metal and the backbone choice with regards to L X Cr AM (Table ), although no obvious trends could be identified. This suggest that an