Excited-State Dynamics of Non-Luminescent and Luminescent π-Radicals

Recently, the potential use of organic π-radicals and related spin systems has been expanded to modern technological applications. The unique excited-state dynamics of organic π-radicals can be useful to improve the stability of photochemically unstable organic compounds, make the polarization transfer applicable to information technology, and achieve effective up-conversion of interest for luminescence bioimaging, among others. Furthermore, highly luminescent stable π-radicals have been recently reported, which are especially interesting for application in organic light-emitting devices owing to their potential to provide an internal quantum efficiency of 100 %. Thus, the excited-state nature of stable π-radicals as well as the control of their excited-state spin dynamics are emerging topics both in terms of fundamental science and related technological applications. In this minireview, we focus on the excited-state dynamics of both photostable non(weakly)-luminescent and luminescent π-radicals, which are opposites of each other. In particular, we cover the following topics: 1) effective generation of high-spin photoexcited states and control of the excited-state dynamics by using non-luminescent π-radicals, 2) unique excited-state dynamics of luminescent π-radicals and radical excimers, and 3) applications utilizing excited-state dynamics of π-radicals.     

Opposed type double stage cell for Mbar pressure experiment with large sample volume

ABSTRACT

A new opposed type double-stage large volume cell has been developed to compress large volume samples to more than 100?GPa (Mbar) pressure. A pair of second-stage diamond anvils is introduced into the first-stage Paris–Edinburgh press. The double-stage large volume cell allows the generation of ultrahigh pressures using a large culet diameter of the second-stage diamond anvils (diameters of 0.5–1.2?mm). Pressure generation up to 131?GPa has been achieved by using the culet diameter of 0.5?mm. Sample volume of the double-stage large volume cell can be more than ～100 times larger than that of conventional Mbar experiment using a diamond anvil cell. The double-stage large volume cell has a large opening in the horizontal plane for X-ray measurements, which is particularly suited for the multi-angle energy dispersive X-ray diffraction measurement, thus opening a new way of in situ structural determinations of amorphous materials at Mbar pressures.     

Development of Sulfonic-Acid-Functionalized Mesoporous Materials: Synthesis and Catalytic Applications

Sulfonic acid based mesostructures (SAMs) have been developed in recent years and have important catalytic applications. The primary applications of these materials are in various organic synthesis reactions, such as multicomponent reactions, carbon–carbon bond couplings, protection reactions, and Fries and Beckman rearrangements. This review aims to provide an overview of the recent developments in the field of SAMs with a particular emphasis on the reaction scope and advantages of heterogeneous solid acid catalysts.     

In silico modeling of PAX8–PPARγ fusion protein in thyroid carcinoma: influence of structural perturbation by fusion on ligand-binding affinity

Journal of Computer-Aided Molecular Design - Paired box 8 (PAX8)–peroxisome proliferator-activated receptor γ (PPARγ) rearrangement is believed to play an important role in...     

Synthesis,Properties, and π‐Dimer Formation of Oligothiophenes Partially Bearing Orthogonally Fused Fluorene Units

A series of oligothiophenes that incorporate cyclopenta[c]thiophene‐based units bearing spiro‐substituted dialkylfluorene was synthesized. Photophysical measurements indicated that there was no interruption in the conjugation along the oligothiophene backbones, irrespective of the number or position of this unit. Electrochemical measurements showed that the thiophene 7‐mers and 11‐mer exhibit reversible multi‐oxidation waves. The formation of cationic species was clearly observed from UV/Vis/NIR measurements. Furthermore, the UV/Vis/NIR spectra at 223 K under one‐electron oxidation conditions revealed that the unsubstituted thiophene or bithiophene units remained in the absence of intermolecular π–π interactions, whereas the formation of π‐dimeric species was observed for the thiophene 7‐mer containing an unsubstituted terthiophene ( U₃ ) unit. Theoretical calculations indicated that the combination of the U₃ unit and the all‐trans conformation decreased the intermolecular steric repulsion between the fused cyclopentene ring and its facing thiophene, which may contribute to the formation of the dimeric structure.     

Single-pixel camera with hole-array disk

Optical Review - A single-pixel camera is composed of optical coding masks, a photo detector, and a computational decoder as the important feature that it requires no image sensor for imaging, and...     

Homo‐double helix formation of an optically active conjugated polymer bearing carboxy groups and amplification of the helicity upon complexation with achiral and chiral amines

An optically active, m‐terphenyl‐based π‐conjugated polymer bearing carboxy groups was synthesized by the copolymerization of the diethynyl monomer bearing a carboxy group with (S,S)‐2,5‐bis(2‐methylbutoxy)‐1,4‐dibromobenzene using Sonogashira reaction. The copolymer showed a weak circular dichroism (CD) in the main‐chain chromophore region due to a homo‐double helix formation with an excess helical handedness biased by the chiral alkoxy substituents through self‐association. However, upon complexation with achiral amines, such as piperidine, the CD intensity of the polymer significantly increased resulting in the formation of a greater excess one‐handed homo‐double helix via hydrogen‐bonded inclusion complexation with the achiral amines between each strand, leading to the amplification of the helicity. A preferred‐handed homo‐double helix was also induced in the polymer in the presence of nonracemic amines. The effect of the achiral and chiral amines on the homo‐double helix formation was investigated by comparing the CD spectra of the polymer to those of its model dimer. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 990–999