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This study reports the solar light-driven activation of a bicyclic aminoxyl mediator to achieve C–C bond cleavage of a lignin model compound at room temperature using a donor–π-conjugated bridge–acceptor organic dye-based photoelectrochemical system.

The selective cleavage of C-C/C-O linkages represents a key step toward achieving the chemical conversion of biomass to targeted value-added chemical products under ambient conditions. Using photoelectrosynthetic solar cells is a promising method to address the energy intensive depolymerization of lignin for the production of biofuels and valuable chemicals. This feature article gives an in-depth overview of recent progress using dye-sensitized photoelectrosynthetic solar cells (DSPECs) to initiate the cleavage of C-C/C-O bonds in lignin and related model compounds. This approach takes advantage of

All-inorganic halide perovskite nanocrystals (NCs) offer impressive optoelectronic properties for light harvesting, energy conversion, and photoredox applications, with two-dimensional (2D) perovskite NCs further increasing these prospects due to their improved photoluminescence (PL) tuneability, impressive color purity, high in-plane charge transport, and large lateral dimensions which is advantageous for device integration. However, the synthesis of 2D perovskites is still challenging, especially toward large-scale applications. In this study, through the control of surface ligand composition and concentration of a mixture of short (octanoic acid and octylamine, 8-carbon chain) and long (oleic acid and oleylamine, 18-carbon chain) ligands, we have developed an extremely facile ligand-mediated synthesis of 2D CsPbX3 (X = Cl, Br, or mixture thereof) nanoplatelets (NPLs) at room temperature in an open vessel. In addition, the developed method is highly versatile and can be applied to synthesize Mn-doped CsPbX3 NPLs, showing a systematic increase in the total PL quantum yield (QY) and the Mn-dopant emission around 600 nm with increasing Mn and Cl concentrations. The reaction occurs in toluene by the introduction of CsX, PbX2, and MnX2 precursors under ambient conditions, which requires no harsh acids, avoids excessive lead waste, little thermal energy input, and is potentially scalable toward industrial applications.

As a green synthetic approach, visible light-driven photosynthesis is highly desirable in arylation of inert alkyl halides, as they are important precursors in the total synthesis of natural products and pharmaceuticals. However, the high bond dissociation energy of aryl halides is typically out of the range of a single visible-light photon. Here, we propose an essential initiation and subsequent electron-transfer step process for visible light-driven aryl halide reduction, and identify the key pyrrole radical anion intermediate, that acts as the strong reduction species. We propose a photoinduced disproportionation (PDP) approach without the addition of any photocatalysts or additives to afford radical anions of pyrrole derivatives, which have enough reduction power to transfer an electron to aryl halide, giving rise to the corresponding aryl radical to afford the desired C–H arylated heterocyclic product. Once generated, the heterocyclic product can undergo the same photoinduced disproportionation (PDP) process to activate aryl halides, thereby promoting the reaction rate. This unprecedented initiation step, which was carried out in the absence of photocatalysts and additives under ambient conditions, can also be used for coupling a wide range of (hetero)aryl halides and pyrrole derivatives, as well as the synthesis of drug intermediates and biorelevant compounds.

A series of polystyrene-based light harvesting polymers featuring pendant polypyridyl ruthenium complexes has been synthesized. The polymer backbones were prepared by nitroxide-mediated radical polymerization with a variable average molecular weight (Mn) ranging from ∼5500 to ∼24 000 g mol−1. Pendant Ru(II) polypyridyl complexes were grafted to the polymer backbone by azide–alkyne click chemistry to afford chromophore loaded polymers. The resulting polystyrene-based polychromophores with pendant Ru(II) polypyridyl complexes (PS-Ru) were characterized by nuclear magnetic resonance and infrared spectroscopy, confirming the high efficiency of the click grafting. The photophysical and electrochemical properties of the series of PS-Ru polymers were characterized in solution and investigated as a function of polymer chain length and solvent. The electrochemical properties of PS-Ru maintained the characteristics of the individual Ru(II) polypyridyl units. Emission quantum yield and lifetime studies reveal that the metal-to-ligand charge transfer (MLCT) excited states are quenched to a variable extent depending on the molecular weight of the polymers, consistent with intramolecular energy transfer and self-quenching in polymers with longer chain lengths. To support the synthetic effort, molecular dynamics simulations of the polypyridyl ruthenium derivatized polystyrenes in different solvents were conducted.