Self-aggregation of synthetic chlorophyll-c derivative and effect of C17-acrylate residue on bridging green gap in chlorosomal model

Biomimetic light-harvesting antennas via the self-assembly of chemically programmed chlorophylls

The photosynthetic pigment "chlorophyll" possesses attractive photophysical properties, including efficient sunlight absorption, photoexcited energy transfer, and charge separation, which are advantageous for applications for photo- and electro-functional materials such as artificial photosynthesis and solar cells. However, these functions cannot be realized by individual chlorophyll molecules alone; rather, they are achieved by the formation of sophisticated supramolecules through the self-assembly of the pigments. Here, we present strategies for constructing and developing artificial light-harvesting systems by mimicking photosynthetic antenna complexes through the highly ordered supramolecular self-assembly of synthetic dyes, particularly chlorophyll derivatives.

Light-induced Li extraction from LiMn2O4/TiO2 in a water-in-salt electrolyte for photo-rechargeable batteries

Photocharging of high-potential spinel LiMn₂O₄ is demonstrated by using a water-in-salt electrolyte and TiO₂ nanoparticles. In a developed half-cell system with an electron acceptor, Li extraction from LiMn₂O₄ proceeds under the illumination of UV-visible light at an estimated rate of ∼23 mA g^-1. This work paves the way for high-potential cathode materials in photo-rechargeable batteries.

Synthesis and Self-Aggregation of π-Expanded Chlorophyll Derivatives to Construct Light-Harvesting Antenna Models

Chlorosomes are one of the elegant light-harvesting antenna systems in anoxygenic photosynthetic bacteria, whose core is constructed from J-type self-aggregation of bacteriochlorophyll- c, bacteriochlorophyll- d, bacteriochlorophyll- e, and bacteriochlorophyll- f molecules without the influence of polypeptides. Chlorosomal supramolecular models were built up using synthetic porphyrin-type bacteriochlorophyll- d analogues with a methoxycarbonylethenyl, formyl, vinyl, or ethyl group at the 8-position. Their chlorosomal self-aggregates in an aqueous micelle solution showed relatively intense absorption bands around 500-600 nm where antennas of natural oxygenic phototrophs, as well as green sulfur bacteria possessing bacteriochlorophylls- c/ d, absorb light less efficiently; this observation is called the "green gap". Furthermore, the functional chlorosomal models were constructed by simple addition of a small amount of an energy acceptor model bearing a bacteriochlorin moiety to the pigment self-assemblies in an aqueous micelle. The resulting excited energy donor-acceptor supramolecules played the roles of chlorosomal light-harvesting and energy-transfer antenna systems and were efficient at light absorption in the "green gap" region.