Akihiro Shimizu

Smaller can be better: The first example of meta-quinodimethane embedded in an indenofluorene framework has been synthesized. 10,12-Dimesitylindeno[2,1-b]fluorene exhibits extremely low-energy light absorption, despite the small conjugation space of the molecule, which consists of only 20 π electrons.

A new isomer: 11,12-Dimesitylindeno[2,1-a]fluorene was synthesized and isolated in crystal form. The indenofluorene exhibits significant bond-length alternation in the o-quinodimethane structure, limited singlet biradical character, and weakly antiaromatic character. Optical and electrochemical properties suggest that indeno[2,1-a]fluorene derivatives may be candidates for optoelectronic materials. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such

A novel naphthoquinoid singlet biradical (2a) stabilized by phenalenyl rings is prepared by a multistep procedure and is investigated in terms of covalent bonding interactions. The molecule 2a gives single crystals, in which a 1D chain is formed with a very short π-π contact at the overlapping phenalenyl rings. The unpaired electrons in 2a are involved in covalent bonding interactions not only within the molecule but also between the molecules in the 1D chain, and a linear conjugation is made of

Two flavors: Intra- and intermolecular spin–spin interactions of unpaired electrons coexist and correlate in stacks of phenalenyl-based singlet biradicals. The electronic structure of the one-dimensional π–π chain is best represented by the superposition of formulas A and B in terms of the resonating valence-bond (RVB) model. Lower temperatures and higher pressures induce a resonance balance shift to the formula B. Detailed facts of importance to specialist readers are published as ”Supporting I

An anthracene-linked bisphenalenyl Kekulé molecule with very significant singlet biradical character has shown a prominent covalent bonding interaction between molecules in a molecular aggregate. High aromatic stabilization energy in the anthracene linker is responsible for the significant singlet biradical character.

We have developed a new technique, called "local mechanical-stress control" (LMC), to enhance CMOS current drivability. It utilizes high mechanical stress produced by a SiN layer and Ge-ion implantation to selectively relax the stress of the layer. The drive currents of both n- and p-MOSFETs can be improved by controlling the stress of the SiN layer selectively. The effects of LMC become more significant as devices become smaller, and the drive current is estimated to increase by more than 20% i

The synthesis and isolation of hydrocarbons with a triplet ground state in crystalline forms have been sought in materials science. Triangulene is one of the most famous triplet-ground-state benzenoid hydrocarbons. Its unique electronic structure and highly symmetric structure have prompted many scientists to synthesize and isolate triangulene and its derivatives, but all attempts so far to isolate them as crystals have been unsuccessful. Herein we report the synthesis and isolation of a kinetic

π-Conjugated molecules with small highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gaps (Δ<i>E</i>_H-L) have been extensively studied because of their unique optoelectronic properties. Although the expansion of π-conjugation is one of the well-known approaches for designing molecules with small Δ<i>E</i>_H-L values, such an approach inevitably gives large π-conjugated molecules sometimes suffering from synthetic difficulty and low so

Abstract Although organic cathode materials have received significant research interest as cathode materials of lithium‐ion batteries because of sustainability and flexibility, they suffer from lower voltages compared to inorganic materials. To increase the voltage of batteries using organic cathode materials without decreasing the capacity, we studied the effect of the replacement of the CH moieties β to the carbonyl group of quinones with nitrogen atoms. The coordination of N to Li in the redu

Kleiner Lichtabsorber: Das erste Beispiel eines meta-Chinodimethans als Bestandteil eines Indenofluoren-Gerüsts wurde synthetisiert. 10,12-Dimesitylindeno[2,1-b]fluoren zeigt eine extrem niederenergetische Absorption, trotz des kleinen konjugierten Systems des Moleküls, das nur 20 π-Elektronen aufweist. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but ar

Ein neues Isomer: 11,12-Dimesitylindeno[2,1-a]fluoren wurde synthetisiert und kristallin isoliert. Es zeigt eine deutliche Bindungslängenalternanz im kondensierten Ringsystem, einen begrenzten Singulettdiradikalcharakter und einen schwach antiaromatischen Charakter. Seine optischen und elektrochemischen Eigenschaften lassen vermuten, dass sich Indeno[2,1-a]fluorenderivate als optoelektronische Materialien eignen könnten. Detailed facts of importance to specialist readers are published as ”Suppor

Abstract Design, synthesis, and isolation of a Kekulé hydrocarbon with a triplet ground state is described. Its triplet ground state was unambiguously confirmed by ESR experiments, and the structure and fundamental physical properties were also revealed. The key feature of the molecular design is the decrease in the bonding interaction in the singlet state by aromatic stabilization of benzene rings and the increase of the exchange interaction of unpaired electrons which are favorable for the tri