Cyclo[4]pyrrole with - direct linkages.

A cyclo[4]pyrrole bearing pyrrole C()-C() direct linkages, a contracted porphyrin analogue with no -carbon bridge, was synthesized from an oligoketone-related precursor. X-ray crystallography and StrainViz analysis revealed a non-planar structure with a total strain of 20.8 kcal mol.

Propeller-Shaped Blatter-Based Triradicals: Distortion-Free Triangular Spin System and Spin-State-Dependent Photophysical Properties.

Herein, we report the synthesis and properties of triptycene-based C- and C-symmetric stable triradicals. SQUID magnetometry showed the propeller-shaped triradicals were both an antiferromagnetic equilateral triangle spin system with small spin-spin interactions J/k~-120 K and -106 K, leading to ca. 4/6 coexistence of the doublet/quartet states in thermal equilibrium at room temperature.

Synergistic Interplay between Fe-Based Perovskite Oxides and Co in Electrolyte for Efficient Oxygen Evolution Reaction.

Perovskite oxides have been extensively investigated as active electrocatalysts for the oxygen evolution reaction (OER) in alkaline solution. While the OER activity of some perovskite oxides is positively influenced by Fe ions in the electrolyte, the impact of other transition metal ions in the electrolyte remains unclear. In this study, we compared the influence of Co ions intentionally added to the electrolyte on the OER activities of two Fe-based perovskite oxides (BaSrFeO and LaFeO).

Bio-based poly(benzimidazole--amide)-derived N, O co-doped carbons as fast-charging anodes for lithium-ion batteries.

Lithium-ion batteries (LIBs) that can be charged faster while delivering high capacity are currently in significant demand, especially for electric vehicle applications. In this context, this study introduces a less-explored subject: nitrogen and oxygen dual-doped carbons derived from bio-based copolymers, specifically poly(benzimidazole--amide). The synthesis involved varying proportions of benzimidazole to amide, namely, 8.

Boosting charge separation in organic photovoltaics: unveiling dipole moment variations in excited non-fullerene acceptor layers.

The power conversion efficiency (PCE) of organic photovoltaics (OPVs) has reached more than 19% due to the rapid development of non-fullerene acceptors (NFAs). To compete with the PCEs (26%) of commercialized silicon-based inorganic photovoltaics, the drawback of OPVs should be minimized. This drawback is the intrinsic large loss of open-circuit voltage; however, a general approach to this issue remains elusive.

An n-type semiconducting diazaporphyrin-based hydrogen-bonded organic framework.

Significant effort has been devoted to the development of materials that combine high electrical conductivity and permanent porosity. This paper discloses a diazaporphyrin-based hydrogen-bonded organic framework (HOF) with porosity and n-type semiconductivity. A 5,15-diazaporphyrin Ni(ii) complex with carboxyphenyl groups at the positions afforded a HOF due to hydrogen-bonding interactions between the carboxy groups and -nitrogen atoms.

Impacts of heteroatom substitution on the excited state dynamics of π-extended helicenes.

Benzo-annulated aza[9]helicene ([9]AH) and thia[9]helicene ([9]TH) were prepared as novel π-extended heterohelicenes. [9]TH showed a quite short fluorescence lifetime of ∼0.3 ns and intense phosphorescence at low temperature that were attributed to its larger spin-orbit coupling and faster intersystem crossing between pseudo-degenerate S and triplet states.

Nonfullerene Acceptors Bearing Spiro-Substituted Bithiophene Units in Organic Solar Cells: Tuning the Frontier Molecular Orbital Distribution to Reduce Exciton Binding Energy.

The development of nonfullerene acceptors (NFAs), represented by ITIC, has contributed to improving the power conversion efficiency (PCE) of organic solar cells (OSCs). Although tuning the electronic structures to reduce the exciton binding energy (E) is considered to promote photocharge generation, a rational molecular design for NFAs has not been established. In this study, we designed and developed two ITIC-based NFAs bearing spiro-substituted bithiophene or biphenyl units (named SpiroT-DCI and SpiroF-DCI) to tune the frontier molecular orbital (FMO) distribution of NFAs.

Band engineering of layered oxyhalide photocatalysts for visible-light water splitting.

The band structure offers fundamental information on electronic properties of solid state materials, and hence it is crucial for solid state chemists to understand and predict the relationship between the band structure and electronic structure to design chemical and physical properties. Here, we review layered oxyhalide photocatalysts for water splitting with a particular emphasis on band structure control. The unique feature of these materials including Sillén and Sillén-Aurivillius oxyhalides lies in their band structure including a remarkably high oxygen band, allowing them to exhibit both visible light responsiveness and photocatalytic stability unlike conventional mixed anion compounds, which show good light absorption, but frequently encounter stability issues.

π-Extended 9b-Boraphenalenes: Synthesis, Structure, and Physical Properties.

Boraphenalenes, compounds in which one carbon atom in the phenalenyl skeleton is replaced with a boron atom, have attracted attention for their solid-state and electronic structures; however, the construction of boraphenalene skeletons remains challenging because of the lack of suitable methods. Through this study, we showed that the tandem borylative cyclization of -symmetric dehydrobenzo[12]annulenes produces a new class of fully fused boron-atom-embedded polycyclic hydrocarbons possessing a 9b-boraphenalene skeleton. The obtained compounds exhibited high electron-accepting characteristics, and their two-step redox process was reversible in the reductive region, involving interconversion of 9b-boraphenalene between Hückel aromaticity and antiaromaticity.

Strain hardening in biaxially stretched elastomers undergoing strain-induced crystallization.

We reveal strain hardening due to strain-induced crystallization (SIC) in both cross-linked natural rubber (NR) and its synthetic analogue (IR) under planar extension, a type of biaxial stretching where the rubber is stretched in one direction while maintaining the dimension in the other direction unchanged. Utilizing a bespoke biaxial tensile tester, planar extension tests were conducted on geometrically designed and optimally shaped sheet specimens to achieve a uniform and highly strained field. Evident strain hardening due to SIC was observed in both stretching () and constrained () directions when the stretch () exceeded a critical value .

First-principles simulation of an ejected electron produced by monochromatic deposition energy to water at the femtosecond order.

This study uses a time-dependent first-principles simulation code to investigate the transient dynamics of an ejected electron produced in the monochromatic deposition energy from 11 to 19 eV in water. The energy deposition forms a three-body single spur comprising a hydroxyl radical (OH˙), hydronium ion (HO), and hydrated electron (e). The earliest formation involves electron thermalization and delocalization dominated by the molecular excitation of water.

Photocatalyzed Hydrogen Atom Transfer Degradation of Vinyl Polymers: Cleavage of a Backbone C-C Bond Triggered by Radical Activation of a C-H Bond in a Pendant.

In this work, we achieved a triggering degradation of polymers composed of carbon-carbon (C-C) bonded backbone without relying on introduction of labile heteroatom-based bond. The crucial point for the achievement is using vinyl ether (VE) as a comonomer in radical copolymerization of (meth)acrylate for introduction of the carbon-hydrogen (C-H) bonds active for photocatalyzed hydrogen atom transfer (HAT) as triggers in the pendant. Interestingly, methyl methacrylate (MMA)-n-butyl vinyl ether (NBVE) copolymer underwent degradation in acetonitrile in the presence of benzophenone (Ph CO) under UV irradiation at 80 °C.

Carbazole-Dendronized Luminescent Radicals.

A series of carbazole-dendronized tris(2,4,6-trichlorophenyl)methyl (TTM) radicals have been synthesized. The photophysical properties of dendronized radicals up to the fourth generation were compared systematically to understand how structure-property relationships evolve with generation. The photoluminescence quantum yield (PLQY) was found to increase with the increasing generation, and the fourth generation (G4TTM) in cyclohexane solution showed a PLQY as high as 63 % at a wavelength of 627 nm (in the deep-red region) from the doublet state.

Initial yield of hydrated electron production from water radiolysis based on first-principles calculation.

Many scientific insights into water radiolysis have been applied for developing life science, including radiation-induced phenomena, such as DNA damage and mutation induction or carcinogenesis. However, the generation mechanism of free radicals due to radiolysis remains to be fully understood. Consequently, we have encountered a crucial problem in that the initial yields connecting radiation physics to chemistry must be parameterized.

Distance measurements between 5 nanometer diamonds - single particle magnetic resonance or optical super-resolution imaging?

5 nanometer sized detonation nanodiamonds (DNDs) are studied as potential single-particle labels for distance measurements in biomolecules. Nitrogen-vacancy (NV) defects in the crystal lattice can be addressed through their fluorescence and optically-detected magnetic resonance (ODMR) of a single particle can be recorded. To achieve single-particle distance measurements, we propose two complementary approaches based on spin-spin coupling or optical super-resolution imaging.

Designing High-Performing Symmetric Supercapacitor by Engineering Polyaniline on Steel Mesh Surface via Electrodeposition.

Energy storage is one of the most stimulating requirements to keep civilization on the wheel of progress. Supercapacitors generally exhibit a high-power density, have a maximum life cycle, quick charging time, and are eco-friendly. Polyaniline (PANI), a conductive polymer, is considered an efficacious electrode material for supercapacitors due to its good electroactivity, including pseudocapacitive behavior.

Rapid and Selective Photo-degradation of Polymers: Design of an Alternating Copolymer with an o-Nitrobenzyl Ether Pendant.

The development of polymers with on-demand degradability is required to alleviate the current global issues on polymer-waste pollution. Therefore, we designed a vinyl ether monomer with an o-nitrobenzyl (oNBn) group as a photo-deprotectable pendant (oNBnVE) and synthesized an alternating copolymer with an oNBn-capped acetal backbone via cationic copolymerization with p-tolualdehyde (pMeBzA). The resultant alternating copolymer could be rapidly degraded into lower-molecular-weight compounds upon simple exposure to UV irradiation without any reactants or catalysts, while it was sufficiently stable toward heat and ambient light.

Anthranilamide-protected vinylboronic acid: rational monomer design for improved polymerization/transformation ability providing access to conventionally inaccessible copolymers.

We have studied several protecting groups for vinylboronic-acid derivatives as monomers in radical polymerizations with the objective to improve the polymerization ability and C-B bond-cleaving post-transformation performance. Anthranilamide (aam)-protected vinylboronic acid (VBaam) exhibited experimentally a relatively high polymerization activity, which was theoretically corroborated by density functional theory (DFT) calculations that revealed a peculiar effect of the interaction between the aam groups on the polymerization behavior. The VBaam units in the copolymers can subsequently be transformed into vinyl alcohols or into ethylene units through C-B-bond-cleaving side-chain replacement, which affords valuable copolymers such as poly(vinyl alcohol--styrene), poly(ethylene--styrene), and poly(ethylene--acrylate).

The simplest structure of a stable radical showing high fluorescence efficiency in solution: benzene donors with triarylmethyl radicals.

Donor-radical acceptor systems have recently attracted much attention as efficient doublet emitters that offer significant advantages for applications such as OLEDs. We employed an alkylbenzene (mesityl group) as the simplest donor to date and added it to a diphenylpyridylmethyl radical acceptor. The (3,5-difluoro-4-pyridyl)bis[2,6-dichloro-4-(2,4,6-trimethylphenyl)phenyl]methyl radical (MesFPyBTM) was prepared in only three steps from commercially available reagents.

Cyclic arrays of five pyrenes on one rim of a planar chiral pillar[5]arene.

Spatial arrangement of multiple planar chromophores is an emerging strategy for molecule-based chiroptical materials easy and systematic synthesis. We attached five pyrene planes to a chiral macrocycle, pillar[5]arene, producing a set of chiroptical molecules in which pyrene-derived absorption and emission were endowed with dissymmetry by effective transfer of chiral information. The chiroptical response was dependent on linker structures and substituted patterns because of variable interactions between pyrene units.

-Methylamide-structured SB366791 derivatives with high TRPV1 antagonistic activity: toward PET radiotracers to visualize TRPV1.

Transient receptor potential cation channel subfamily V member 1 (TRPV1)-targeted compounds were synthesized by modifying the structure of SB366791, a pharmaceutically representative TRPV1 antagonist. To avoid amide-iminol tautomerization, structurally supported -methylated amides (, 3-alkoxy-substitued -meythylamide derivatives of SB366791) were evaluated using a Ca influx assay, in which cells expressed recombinant TRPV1 in the presence of 1.0 μM capsaicin.

Incorporation of a boryl pendant as the trigger in a methacrylate polymer for backbone degradation.

Alkenylboronate units were incorporated into poly(methyl methacrylate) as trigger sites for backbone degradation. The complexation of a fluoride anion to the boron pendant and subsequent activation by a manganese salt triggered the degradation through the generation of a main-chain carbon radical and β-scission in an adjacent methacrylate unit. The addition of catechol was required, and presumably the chelate coordination to the Mn center was crucial for the degradation.