A simple and straightforward polymer post-modification method for wearable difluoroboron β-diketonate luminescent sensors

Abstract

Boron-containing polymeric materials represent an important class of functional polymers, whereas their preparation usually requires multiple synthetic steps. Here we report a simple and straightforward polymer post-modification method to attach difluoroboron β-diketonate (BF2bdk) luminescent moieties onto polymer chains as side groups. The post-modification, using poly (N-vinyl carbazole) (PVK) as aromatic substrates, has been found to occur at ambient conditions via a cascade manner in the presence of acetic anhydride and boron trifluoride diethyl etherate. The obtained PVK-BF2bdk polymeric materials have been found to function as wearable luminescent sensors to display switching-on property upon exposing to alcohol and show switching-off behavior in organic acid environment. Detailed studies reveal that the post-modification also produces crosslinking points formed by pyrylium salt structures. The pyrylium structures, which are well solvated in organic acids and show UV–vis absorption largely overlapped with BF2bdk emission, cause the switching-off behaviour of the PVK-BF2bdk polymeric materials.