Chirality in Singlet Fission: Controlling Singlet Fission in Aqueous Nanoparticles of Tetracenedicarboxylic Acid Ion Pairs.

The singlet fission characteristics of aqueous nanoparticles, self-assembled from ion pairs of tetracene dicarboxylic acid and various amines with or without chirality, are thoroughly investigated. The structure of the ammonium molecule, the counterion, is found to play a decisive role in determining the molecular orientation of the ion pairs and its regularity, spectroscopic properties, the strength of the intermolecular coupling between the tetracene chromophores, and the consequent singlet fission process. Using chiral amines has led to the formation of crystalline nanosheets and efficient singlet fission with a triplet quantum yield as high as 133% ±20% and a rate constant of 6.

Spin-Polarized Radicals with Extremely Long Spin-Lattice Relaxation Time at Room Temperature in a Metal-Organic Framework.

The generation of spin polarization is key in quantum information science and dynamic nuclear polarization. Polarized electron spins with long spin-lattice relaxation times () at room temperature are important for these applications but have been difficult to achieve. We report the realization of spin-polarized radicals with extremely long at room temperature in a metal-organic framework (MOF) in which azaacene chromophores are densely integrated.

Photoliquefaction and phase transition of -bisazobenzenes give molecular solar thermal fuels with a high energy density.

A series of -bisazobenzene chromophores modified with various alkoxy substituents (1; methoxy, 2; ethoxy, 3; butoxy, 4; neopentyloxy) were developed for solvent-free molecular solar thermal fuels (STFs). Compounds (,)-1-3 in the crystalline thin film state exhibited photoliquefaction, the first example of photo-liquefiable -bisazobenzenes. Meanwhile, (,)-4 did not show photoliquefaction due to the pronounced rigidity of the interdigitated molecular packing indicated by X-ray crystallography.

Visible-to-UV Photon Upconversion in Nanostructured Chromophoric Ionic Liquids.

Visible-to-ultraviolet (vis-to-UV) triplet-triplet annihilation based photon upconversion (TTA-UC) is achieved in a non-volatile chromophoric ionic liquid (IL) for the first time. A novel IL is synthesized by combining UV-emitting anion 4-(2-phenyloxazol-5-yl)benzenesulfonate (PPOS) and trihexyltetradecylphosphonium cation (P). The nanostructured organization of chromophoric anions is demonstrated by synchrotron X-ray and optical measurements.

Visible-to-UV Photon Upconversion in Nanostructured Chromophoric Ionic Liquids.

Invited for this month's cover picture is the group of Professor Nobuhiro Yanai and Nobuo Kimizuka at Kyushu University. The cover picture shows visible-to-ultraviolet (vis-to-UV) triplet-triplet annihilation-based photon upconversion (TTA-UC) via triplet exciton diffusion in a chromophoric ionic liquid (IL). Chromophore moieties spontaneously form continuous arrays in non-polar nano-domains of the IL.