Stack Exchange Strategies for the Synthesis of Covalent Double-Channel Photosystems by Self-Organizing Surface-Initiated Polymerization

Abstract

Ring-opening disulfide exchange polymerization has recently been identified as ideal for synthesizing single-channel photosystems by self-organizing surface-initiated polymerization (SOSIP). Here we introduce chemoorthogonal hydrazone exchange chemistry to engineer additional channels into single-channel photosystems. Post-SOSIP stack exchange is shown to provide facile access to complete supramolecular n/p-heterojunction architectures with high activity and freely variable composition, including oriented antiparallel redox gradients. With appropriate templation from the surface, post-SOSIP stack exchange is nearly quantitative.

Interfacing Functional Systems

“…Orthogonal to disulfide exchange, hydrazone exchange under acidic conditions is used to add π stacks along the original stacks in primary system 5. [14] The resulting secondary system 6 contains co-axial channels that transport holes and electrons separately. Charge separation into these coaxial channels can be named as unifying emergent property of double-channel photosystem 6 that affects several functional readouts.…”

“…Limited only by our imagination, functional components or systems conceivable for interfacing reach from additional simple but meaningful functional groups to solid surfaces, [5,[13][14][15][16][17] proteins, [6] polymersomes, [9] liposomes, [3] cells, [4] and so on. Success with MSE will ultimately be judged from the significance, practical or conceptual, of the emergent properties obtained.…”

“…[4,5,[13][14][15][16][17] For systems interfacing, this dual nature promises access to self-sorting, self-healing, adaptability, templation, amplification, replication, transcription, and so on. [18] These expected advantages of dynamiccovalent chemistry for systems engineering have been validated with multicomponent photosystems on solid surfaces (Figs 4 and 5).…”

“…[18] These expected advantages of dynamiccovalent chemistry for systems engineering have been validated with multicomponent photosystems on solid surfaces (Figs 4 and 5). [5,[13][14][15][16][17] A chromophore is taken as a primary component with absorption and emission as intrinsic properties. The alignment of these primary components in oriented π stacks on conducting solid oxide surfaces affords primary system 5 (Fig.…”

“…[23] Despite the hydrophobic mismatch, the polymer membrane of these compartments represents an excellent platform for membrane proteins, synthetic pores or bio-pores interfacing. Polymersomes or liposomes equipped with membrane proteins, synthetic pores or photosystems are secondary systems (14). [3,[24][25][26][27] For example, the insertion of the ion selective bio-pore gramicidin into PMOXA-b-PDMS-b-PMOXA polymersomes allowed H + , Na + or K + ions to pass through the membrane and quench the fluorescence of encapsulated pyranine.…”