An elastic organic crystal of a π-conjugated molecule has been fabricated. A large fluorescent single crystal of 1,4-bis[2-(4-methylthienyl)]-2,3,5,6-tetrafluorobenzene (over 1 cm long) exhibited a fibril lamella morphology based on slip-stacked molecular wires, and it was found to be a remarkably elastic crystalline material. The straight crystal was capable of bending more than 180° under applied stress and then quickly reverted to its original shape upon relaxation. In addition, the fluorescence quantum yield of the crystal was about twice that of the compound in THF solution. Mechanical bending-relaxation resulted in reversible change of the morphology and fluorescence. This research offers a more general approach to flexible crystals as a promising new family of organic semiconducting materials.

To create lowb and-gap,f luorescent, and elastic organic crystal emitters,w ef ocused on an extended pconjugated system based on:a )aplanar conformation,b) arigid structure,and c) controlled intermolecular interactions. Herein, we report on two fluorescent and highly flexible organic crystals (1 and 2)whichcould bend under an applied stress.T he bent crystals rapidly recover their straight shape upon release of the stress.C rystal 1 with at etrafluoropyridyl terminal unit and al ower band-gap energy (orange emission, l em = 573 nm, F F = 0.50), showed no bending mechanofluorochromism and had superior performance as an optical waveguide with reddish orange emission. The waveguide performance of the crystal did not decrease under bending stress.F or crystal 2 with ap entafluorophenyl terminal unit (green emission, l em = 500 nm, F F = 0.38), the original waveguide performance decreased under an applied bending stress; however,this crystal showed aunique bending mechanofluorochromism.

Elastic organic crystals have attracted considerable attention as next‐generation flexible smart materials. However, the detailed information on both molecular packing change and macroscopic mechanical crystal deformations upon applied stress is still insufficient. Herein, we report that fluorescent single crystals of 9,10‐dibromoanthracene are elastically bendable and stretchable, which allows a detailed investigation of the deformation behavior. We clearly observed a Poisson effect for the crystal, where the short axes (b and c‐axes) of the crystal are contracted upon elongation along the long axis (a‐axis). Moreover, we found that the Poisson's ratios along the b‐axis and c‐axis are largely different. Theoretical molecular simulation suggests that the tilting motion of the anthracene may be responsible for the large deformation along the c‐axis. Spatially resolved photoluminescence (PL) measurement of the bent elastic crystals reveals that the PL spectra at the outer (elongated), central (neutral), and inner (contracted) sides are different from each other.

The phytohormone abscisic acid (ABA) plays pivotal roles in the regulation of developmental and environmental responses in plants. Identification of cytoplasmic ABA receptors enabled the elucidation of the main ABA signalling pathway, connecting ABA perception to either nuclear events or the action of several transporters. However, the physiological functions of ABA in cellular processes largely remain unknown. To obtain greater insight into the ABA response, genetic screening was performed to isolate ABA-related mutants of Arabidopsis and several novel ABA-hypersensitive mutants were isolated. One of those mutants—ahg11—was characterized further. Map-based cloning showed that AHG11 encodes a PPR type protein, which has potential roles in RNA editing. An AHG11-GFP fusion protein indicated that AHG11 mainly localized to the mitochondria. Consistent with this observation, the nad4 transcript, which normally undergoes RNA editing, lacks a single RNA editing event conferring a conversion of an amino acid residue in ahg11 mutants. The geminating ahg11 seeds have higher levels of reactive-oxygen-species-responsive genes. Presumably, partial impairment of mitochondrial function caused by an amino acid conversion in one of the complex I components induces redox imbalance which, in turn, confers an abnormal response to the plant hormone.

A versatile synthetic means for cyclic diblock copolymers has been developed by the combination of atom transfer radical polymerization (ATRP) and ring-closing metathesis (RCM) techniques. Thus, first, an A−B type allyl-telechelic diblock copolymer comprised of two different acrylate ester segments, i.e., poly(methyl acrylate)-b-poly(n-butyl acrylate), poly(MA)-b-poly(BA), was prepared via the ATRP of MA, followed by the addition of the second monomer, BA, with allyl bromide as an initiator and with allyltributylstannane as an end-capping reagent, respectively. Alternatively, an A−B−A type allyl-telechelic triblock copolymer comprised of poly(BA) and poly(ethylene oxide), poly(EO), segments was prepared via the ATRP of BA using a poly(EO) macroinitiator having 2-bromoisobutyryl end groups, followed by the end-capping reaction with allyltributylstannane. The subsequent RCM of the allyl-telechelic block copolymers under dilution in the presence of Grubbs catalyst could afford the corresponding A−B type cyclic diblock copolymers.