Polythioamides from multicomponent benzoxazine-isocyanide-chemistry: Room temperature synthesis and post-polymerization to construct functional polythioesteramide.

[Display omitted] • Thioacetamide (TAA)-involved benzoxazine-isocyanide-chemistry (BIC) was exploited. • Polythioamides (PTAs) were prepared from this reaction at room temperature. • A cross-linked polythioesteramide derivative (PTA2-TMC) was prepared subsequently. • PTA2-TMC can be applicated as an enrichment-type Pb (II) electrochemical probe. The traditional syntheses of polythioamides (PTAs) are significantly restricted by the narrow substrate selection and harsh reaction conditions, limiting the further development of such polymers. In this study, by introducing thioacetamide (TAA) into the reaction system as a suitable sulfur source, small-molecular model thioamide compounds (BHPET, BPFET and BFHET) were successfully prepared through benzoxazine-isocyanide-chemistry (BIC) at room temperature under metal-free condition. The feasibility of this reaction system in the preparation of phenolic –OH substituted, linear PTAs (PTA1-A/B/C) were subsequently investigated, and the possible reaction mechanism was proposed. Post-polymerization modification of polybenzoxazine to prepare polymer (PTA2) with side-chain thioamide segments was also accomplished here. In addition, cross-linked polythioesteramide derivatives (PTA1-A-TMC and PTA2-TMC) was prepared by condensation between representative synthesized PTAs (PTA1-A and PTA2-3) and trimesoyl chloride (TMC). Thanks to the presence of multiple Pb2+-affinitive units (thioamide, amide, phenolic hydroxyl, tertiary amine and carboxyl) in such PTAs' structure, the application of PTA2-TMC (as the representative sample) as Pb2+ electrochemical probe was explored further. This work can provide new thought for the mild-condition preparation, structural post-modification and functional application of novel PTAs. [ABSTRACT FROM AUTHOR]