Polyampholytic Graft Copolymers as Matrix for TiO2 /Eosin Y/[Mo3 S13 ]2- Hybrid Materials and Light-Driven Catalysis.

An effective strategy to enhance the performance of inorganic semiconductors is moving towards organic-inorganic hybrid materials. Here, we report the design of core-shell hybrid materials based on a TiO2 core functionalized with a polyampholytic (poly(dehydroalanine)-graft-(n-propyl phosphonic acid acrylamide) shell (PDha-g-PAA@TiO2 ). The PDha-g-PAA shell facilitates the efficient immobilization of the photosensitizer Eosin Y (EY) and enables electronic interactions between EY and the TiO2 core. This resulted in high visible-light-driven H2 generation. The enhanced light-driven catalytic activity is attributed to the unique core-shell design with the graft copolymer acting as bridge and facilitating electron and proton transfer, thereby also preventing the degradation of EY. Further catalytic enhancement of PDha-g-PAA@TiO2 was possible by introducing [Mo3 S13 ]2- cluster anions as hydrogen-evolution cocatalyst. This novel design approach is an example for a multi-component system in which reactivity can in future be independently tuned by selection of the desired molecular or polymeric species.

Different Routes to Ampholytic Polydehydroalanine: Orthogonal versus Simultaneous Deprotection.

Polydehydroalanine (PDha) is a polyampholyte featuring both a -NH2 and a -COOH in every repeat unit and with that presents a rather high charge density. The synthesis and polymerization of two monomers, benzyl 2-tert-butoxycarbonylaminoacrylate and methyl 2-benzyloxycarbonylaminoacrylate is herein reported, which feature different protective groups and, after polymerization, the resulting PtBABA and PBOMA can be transformed into PDha using polymer-analogous modification reactions. More important, the current choice of protective groups allows either simultaneous deprotection in one step in both cases, but also the orthogonal deprotection of either -NH2 or -COOH moiety for PtBABA, given that appropriate conditions are chosen. The polymers are prepared using free radical polymerization and all (intermediate) polymeric materials are investigated using a combination of NMR spectroscopy and size exclusion chromatography.