Polymer-bound pyrene-4,5,9,10-tetraone for fast-charge and -discharge lithium-ion batteries with high capacity.

Organic rechargeable batteries have received significant research interest from the viewpoints of structural diversity and sustainability of electrode materials. We designed core structures of organic cathode materials for lithium-ion (Li-ion) batteries based on density functional theory (DFT) calculations, which indicated that six-membered cyclic 1,2-diketones serve as excellent core structures because of the high redox energy change resulting from favorable coordination of the oxygen atoms to Li and the aromaticity of the reduced form. Here, we show that the Li-ion battery composed of pyrene-4,5,9,10-tetraone (PYT), which has two six-membered cyclic 1,2-diketone units, bound to polymethacrylate exhibits remarkable charge-discharge properties with a high specific capacity of 231 mAh/g, excellent rechargeability (83% of the capacity retained after 500 cycles), and charge-discharge ability (90% of the capacity at 30 C as compared to 1 C) in the LiNTf(2)/tetraglyme ionic-liquid system.

Iterative molecular assembly based on the cation-pool method. Convergent synthesis of dendritic molecules.

An iterative method for molecular assembly has been developed based on the cation-pool method using (trimethylsilyl)diphenylmethane as a building block. The silyl group works as both an activating group of the benzene ring in the Friedel-Crafts type reaction and an electroauxiliary in the subsequent low temperature anodic oxidation to generate dendritic diarylcarbenium ions, which were well characterized by low-temperature NMR spectroscopy. The convergent synthesis of dendritic molecules has been achieved by repeating the sequence.

Electrochemical generation of glycosyl triflate pools.

Glycosyl triflates, which serve as important intermediates in glycosylation reactions, were generated and accumulated by the low-temperature electrochemical oxidation of thioglycosides such as thioglucosides, thiogalactosides, and thiomannosides in the presence of tetrabutylammonium triflate (Bu(4)NOTf) as a supporting electrolyte. Thus-obtained solutions of glycosyl triflates (glycosyl triflate pools) were characterized by low-temperature NMR measurements. The thermal stability of glycosyl triflates and their reactions with glycosyl acceptors were also examined.