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Cyclosiloxanes directly bearing polyaromatic groups on silicon atoms have scarcely been reported. Herein, hexa(1-pyrenyl)cyclotrisiloxane (

The intramolecular Diels-Alder reactions of helicenes deform their π-conjugated screw-shaped skeletons. In particular, terminally tetrafluorinated [7]helicene (F4 -[7]helicene) undergoes a photoinduced Diels-Alder reaction followed by a photoinduced double fluorine atom transfer. Herein, we thoroughly investigated this photochemical domino process by decreasing the level of fluorine substitution. F3 -[7]Helicenes bearing two fluorine atoms at the dienophile terminal underwent photoinduced Diels-Alder reactions, but the whole domino process became slow. F2 -[7]Helicene, which is difluorinated only at the dienophile terminal, was also photolabile. As a result, two fluorine atoms were sufficient for the photochemical domino reaction to occur. X-ray crystallographic analysis revealed that F2 -[7]helicene was less compressed than F4 -[7]helicene, indicating that terminal polyfluorination enhanced the intramolecular arene-fluoroarene stacking interactions and thus promoted the transformations.

Activated crystals of a supramolecular assembly of bromothiacalix[4]arene propyl ether with preorganized channel-like voids can selectively and effectively adsorb isooctane vapor from a vapor mixture of isooctane and n-heptane.

High color-purity emission with a minimum full width at half maximum (FWHM) is critical for high-resolution displays. Despite the increasing demand for narrow-band emission materials with multi-resonance-induced thermally activated delayed fluorescence (MR-TADF), their development remains challenging from the viewpoint of synthetic chemistry. In this study, we developed a novel one-pot borylation method that does not require the use of hazardous tert-BuLi, and for which the starting materials are not limited to aromatic fluorides and carbazole-based materials. We achieved this by making simple modifications to a boron–nitrogen skeleton. By inserting carbon and oxygen into the skeleton, we created two types of highly efficient green-emitting MR-TADF emitters, namely DMAc-BN and PXZ-BN. This design enabled the suppression of aggregation-induced quenching, which was one of the major challenges faced by MR-TADF emitters developed in the past. OLEDs using our DMAc-BN and PXZ-BN emitters exhibited external quantum efficiencies of 20.3% and 23.3%, respectively, with FWHM values of 49 and 47 nm, respectively. PXZ-BN exhibited pure green emission with CIE coordinates of (0.22, 0.67).

Controlling the molecular orientation of materials is a key issue for improving the performance of organic semiconductor devices. Herein, we demonstrate the structure-property relationships of iodinated and noniodinated molecules based on an asymmetric thienoacene framework. The noniodinated molecule formed an antiparallel slip-stack structure with small orbital overlap between molecules. In contrast, the iodinated molecule formed a head-to-head layered-herringbone structure, and as a result, the transfer integrals became larger and the hole mobility increased significantly compared with the noniodinated material. The iodinated molecule was made into a stable and solution-processable p-type organic semiconductor with a mobility of 2.2 cm2 V-1 s-1, which was 2 orders of magnitude higher than that of the noniodinated molecule. This study reveals that controlling molecular orientations using iodine-iodine interactions is a promising strategy for accelerating the development of organic semiconductor materials.

A series of dialkylated dinaphtho[2,1-b:2′,1′-f]thieno[3,2-b]thiophenes (S-DNTTs) featuring an S-shaped sinuous π-core substituted with different alkyl chains were developed as versatile p-type org...

The partial fluorination of polycyclic aromatic hydrocarbons often produces a layered crystal packing, where fluorinated aromatic surfaces are stacked over nonfluorinated aromatic surfaces. Herein, we report the synthesis and crystal packing of partially fluorinated [4]helicenes with steric congestion resulting from H and F atoms in the fjord region. F6 -[4]Helicene forms head-to-tail columnar stacks consisting of an alternate arrangement of perfluorinated and nonfluorinated naphthalene moieties. With decreasing fluorine content, aromatic stacking switched from arene-fluoroarene (ArH -ArF ) hetero-stacking to ArH -ArH /ArF -ArF homo-stacking with the help of intermolecular C-H⋅⋅⋅F contacts in the fjord region. As a result, head-to-head columnar stacks appear. Therefore, the conventional ArH -ArF stacking motif is not always applicable to Fn -[4]helicenes with twisted π-surfaces.

Herein we describe the structure–property relationships of three biazulene isomers (2,6′-biazulene (BAz1), 2,2′-biazulene (BAz2), and 6,6′-biazulene (BAz3)). The unimolecular planarities of these m...

Tri- and tetra-fluorinated [7]helicenes are photolabile and undergo a double fluorine atom transfer. Herein, we show that the transferred product further undergoes a skeletal transformation on silica gel. The transformation begins with activation of the allylic C-F bond on the silanol surface. Then, the resulting carbocation readily undergoes a regioselective nucleophilic aromatic substitution with water, depending on the position of the fluorine substituents. Hexafluoro-2-propanol also activated the allylic C-F bond and acted as a nucleophile. These findings support the generation of a highly reactive cationic electrophilic intermediate in the successive transformations involving fluorine atoms.

A new Rh(III) separation method using metal-containing hydrochloric acid (HCl) solutions has been developed. This method includes Rh(III) precipitation with high selectivity using aromatic primary diamines as precipitants. The compound p-phenylene diamine dihydrochloride (PPDA) successfully precipitates only Rh(III) from HCl solutions containing Pd(II), Pt(IV), and Rh(III). Furthermore, highly selective Rh(III) recovery from the simulated spent catalyst leach solution, comprising Pd, Pt, Rh, Ce, Al, Ba, Zr, La, and Y in 5 M HCl, was achieved using PPDA. Single-crystal X-ray analysis revealed that the Rh(III)-containing precipitate using PPDA forms three-dimensional ionic crystals comprising the [RhCl6]3–/ammonium form of PPDA/chloride anion/H2O at a 1:2:1:2 ratio. Formation of these unique ionic crystals plays a key role in the highly selective Rh(III) recovery. This Rh(III) recovery method will be promising for use in the purification process of Rh as well as the practical Rh recovery from spent catalysts.

The orbital degeneracy of benzene rings is resolved by an asymmetric push-pull system in 2,6-bis(methylsulfonyl)aniline (BMeSA), in which the highest occupied molecular orbital (HOMO) is located at the 4-position, while the lowest unoccupied molecular orbital (LUMO) is located at a different position and has a nodal plane through the carbon atoms at the 1- and 4-positions. Therefore, the π-extension of BMeSA at the 4-position reveals a strong overlap in the HOMO and a minimal overlap in the LUMO. Consequently, π-extended BMeSA derivatives exhibit longer absorbance and emission wavelengths in the order of the electron-donating abilities of their substituents at the 4-position, which is based on a decrease in an absolute HOMO-level-dependent HOMO-LUMO gap in accordance with the nodal arrangement. Positive fluorescent solvatochromism with polarity-dependent decrease in fluorescent intensity was also observed. The biaryls exhibited more planar geometries in the excited state than in the ground state. The charge transfer mechanism, which can be described as node-induced intramolecular charge transfer (NICT), differs from the planar intramolecular charge transfer (PICT) and twisted intramolecular charge transfer (TICT).

A series of chrysene-based electron-transporters named BnPyPCs (n = 2, 3, 4) end-capped with two 3,5-di(pyridin-n-yl)phenyl moieties with high thermal and electrical stability were successfully dev...

A novel series of hole-transporters for organic light-emitting devices (OLEDs) was developed with the aim of high thermal and electrical stability. This was achieved by introducing [1]benzothieno[3...

Rhodium (Rh) is the most expensive platinum group metal (PGM) and is of great industrial importance. Although the recycling of PGMs from secondary sources is in high demand, the preferential and selective separation of Rh from PGM mixtures remains a great challenge. Here, a selective Rh separation method involving the precipitation of Rh from an HCl solution containing palladium (Pd), platinum (Pt), and Rh is reported. 4-Butylaniline and 4-hexylaniline were used as precipitants for Rh, and selective Rh precipitation was achieved at high HCl concentrations. We revealed that Rh in HCl selectively forms a unique and highly stable ion-pair complex comprising [RhCl6]3-/anilinium/chloride ions in a 1:6:3 ratio. The formation and high stability of the Rh complex were found to play important roles in the selective recovery of Rh from PGM mixtures.

Two compounds, 2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN), which has a single anthracene unit, and 10,10′-diphenyl-9,9'-bianthracene (PPBA), which has two spatially orthogonal anthracene units, were compared and investigated in terms of photoelectric characteristics and the reverse intersystem crossing (RISC) process in organic light emitting diodes (OLEDs). Transient electroluminescence (EL) measurements indicated large contributions of triplet–triplet annihilation (TTA) for MADN but almost no contribution of TTA for PPBA. The magnetic field dependence of EL for the two anthracene compounds was also different. The EL of MADN was sensitive to the magnetic field at high current density, but PPBA showed less dependence, which indicated the absence of the TTA process for PPBA. TD-DFT calculations revealed that PPBA has doubly degenerate lowest triplet states (T1 and T2) with a much lower energy than S1, which is unfavorable for thermally activated delayed fluorescence (TADF). The near-zero ΔEST between highly excited states Sm≥1 and Tn>2 is favorable to RISC at a highly excited state. Oxygen quenching of photoluminescence only for PPBA and decreasing EL intensity with decreasing temperature only for PPBA support the existence of the RISC path from Tn>2 to Sm≥1. A high external quantum efficiency of 11% in blue OLEDs with PPBA was obtained, indicating that this orthogonal anthracene type of molecular design for RISC at a highly excited state would expand the material development of compounds emitting blue fluorescence for OLEDs.

With the remarkable improvement in the electrical and optical properties of organic light-emitting diodes (OLEDs) in recent years, the details of the higher-order structure of vacuum-deposited amorphous organic films and its formation mechanism need to be understood. In particular, to clarify the effect of the higher-order structure on the film properties, it is necessary to analyze the molecular aggregation states in the vacuum-deposited amorphous films. Toward their deep understanding, the higher-order structure and film properties have often been discussed with relation to the surface diffusion and structural relaxation of the molecules immediately after deposition on the film surface. However, the effect of the variety of conformers, which is specific to amorphous organic materials, on the thermal and electrical properties of the films has not been deeply discussed. In this study, we focused on three structural isomers of OLED materials and discuss the effect of the conformer distribution on the molecular aggregation states and thermal and electrical properties of the vacuum-deposited films. From their comparison, we found that the properties of the film composed of a relatively small number of stable conformers are superior to those of the other two films composed of relatively large numbers of stable conformers. This superiority originates from formation of aggregates of the same conformer, which become the starting points for crystallization when the film is heated. Our detailed comparison and discussion focusing on the variety of conformers will lead to a deeper understanding of the molecular aggregation states and physical properties of amorphous organic films.

Light metal complexes, such as lithium (Li), sodium (Na), magnesium (Mg), and aluminum (Al) complexes, are attractive candidates for the fabrication of thermally activated delayed fluorescent (TADF) materials. Nevertheless, mononuclear Al complexes with delayed fluorescence have not been developed so far. In this study, we successfully developed a novel series of highly luminescent Al complexes with two phenylacridine-modified asymmetric acetylacetonate-type ligands. These complexes exhibit high photoluminescence quantum yields (PLQYs) of up to 79 % in the solid state with a short delayed fluorescence lifetime of approximately 4 μs. Solution-processed organic light-emitting devices (OLEDs) using these Al complexes exhibit excellent performance with an external quantum efficiency of 17.5 % at 100 cd m-2 . This is the best performance in light metal-based TADF OLEDs reported so far. The results are expected to guide the advancement of the next-generation solid-state lighting technology.

Alkanes composed of C-C and C-H show a low electric polarization, and therefore, there is only very weak interaction between alkanes and adsorbents. Thus, it is difficult to separate a specific alkane from a mixture of alkanes by adsorption. Here, two activated "channel-like" crystals generated from brominated thiacalix[4]arene propyl ethers, which adopt 1,3-alternate and partial cone conformations, recognize specific alkane vapors depending on alkane-shape and -size, sorting in three-type alkane guests such as linear, branched, and cyclic alkanes. Two activated crystals, which are prepared by removal of solvent upon heating under reduced pressure, incorporate branched and/or cyclic alkane vapors by a unique "gate-opening" mechanism via a crystal transformation in the process. Linear alkane vapors do not trigger gate opening and are not taken up by the activated crystals. The shape and size molecular-recognition properties of the activated crystals promises considerable usefulness for the separation of linear, branched, and cyclic alkanes.

Azulene is a non-alternant non-benzenoid hydrocarbon that has attracted much attention because of its large dipole moment and long-wavelength absorption properties that are derived from its unique molecular orbital geometry; its highest occupied and lowest unoccupied molecular orbitals are not mirror images. In this chapter, we describe the synthesis, structures, properties, and organic field-effect transistor (OFET) characteristics of 2-azulenyl end-capped oligomers and 2, 6-connected terazulene isomers, in which the azulene moieties deliver molecules that are flat and linear. These compounds show high-order orientations with herringbone packing in their crystalline states and typical OFET characteristics with high carrier mobilities. In particular, terazulene isomers are unique π-conjugated systems with asymmetrically distributed molecular orbitals, which leads to an unconventional concept: polarity control of OFET by molecular orbital distribution control. These findings provide a key approach for constructing various OFET materials and a basis for the accelerated development of the solid-state chemistry of azulene.

Six butadiyne monomers with (dimethylamino)phenyl and N-substituted urethane substituents were synthesized and their crystal structures and solid-state polymerization were investigated. In five of the six monomers, directions of the butadiyne stacking and the intermolecular hydrogen bonding between urethane groups coincided, and translational distance d between adjacent butadiyne moieties was around 5 A. Among them, four monomers showed angle θ between the translation axis of the monomers and the butadiyne moiety of around 45°, which is appropriated for regular 1,4-addition polymerization. These geometries resulted in formation of polydiacetylenes with characteristic excitonic absorption and relatively high conversion. One monomer was found to have large θ, and the regular polymerization was not recognized to be quite low conversion. However, in the remaining one monomer among six, the directions of butadiyne stacking and intermolecular hydrogen bonding were different and d was much longer than 5 A. Howev...

Fe-based cathode materials pyrolyzed with a Zn compound such as ZIF-8 are promising as non-platinum oxygen reduction reaction (ORR) catalysts. However, the ZIF-8 is not sufficient to reduce the cost of fuel cells. Here we report new metal/nitrogen/carbon-electrocatalysts synthesized by the pyrolysis of precursors consisting of Ketjenblack®, a Zn complex with 4,4′-bipyridine, 1,10-phenanthroline (phen), and iron(II) chloride, first in argon at 1050 °C, then ammonia at 950 °C. It is elucidated that the addition of the zinc complex and phen to the precursors promotes formation of pyridinic and graphitic nitrogen to improve the ORR activity. The onset potential defined by 100 μA mg−1 for ORR was 0.876 V vs. RHE with the catalyst containing all the ingredients. Based on the results of accelerated durability tests and XPS measurements, it was considered that there were two oxygen reduction catalytic sites consisting of pyridinic and graphitic nitrogen species on the surface of the catalysts.

Donor-type and acceptor-type 9,9′-bifluorenylidene derivatives, MOBF and CNBF, were synthesized. Suitable energy levels on the excited states of the compounds for singlet fission were revealed by density functional theory calculation. Thermal and optoelectronic properties of the compounds were investigated, and the OPV devices with the donor-type MOBF and the acceptor-type CNBF were fabricated. MOBF showed large dependence of photocurrent on magnetic field, suggesting the singlet fission behavior in the OPV device. On the other hand, CNBF did not show any magnetic field dependence of photocurrent, probably because of poor morphology.

The prognosis of patients with recurrent/persistent endometrial cancer, particularly type II cancer, remains poor, and effective treatment has not yet been established. We herein present the case of a patient with recurrent type II endometrial cancer who received bevacizumab + chemotherapy continued beyond progression, after previously receiving bevacizumab + chemotherapy. This patient experienced recurrence after first- and second-line adjuvant chemotherapy followed by modified radical hysterectomy and she was administered bevacizumab + paclitaxel + carboplatin therapy. After six cycles of treatment, all metastatic lesions shrunk, indicating partial response. The patient next received single-agent bevacizumab as maintenance therapy. After 12 cycles of bevacizumab monotherapy, disease progression was detected; therefore, combination therapy consisting of bevacizumab, doxorubicin and carboplatin was initiated. After six cycles of this combination therapy, the patient exhibited disease stabilization. Finally, 18 months after the initial bevacizumab treatment, the patient remained on combination chemotherapy, without complaints or signs of tumor progression (last follow-up, October 2014).

Novel double helices covalently bridged by cyclic boronate esters were synthesized from complementary dimers with an m-terphenyl backbone joined by a chiral or achiral phenylene linker bearing diethyl boronates and diols, respectively. The X-ray crystallographic analysis and variable-temperature NMR and circular dichroism measurements, along with theoretical calculations, revealed that the double helices function as a "molecular rotor" in which the cyclic boronate ester units rotate, yielding two stable rotamers at low temperatures. Moreover, our data indicates that the covalently bonded double helices can undergo a unique helix-inversion simultaneously with a rotational motion of the boronate esters.

Anthra[2,3-b]thieno[2,3-d]thiophene (ATT), which is readily accessed from thieno[3,2-b]thiophene and 2,3-naphthalenedicarboxylic anhydride, allows for selective substitution at the terminal thiophene ring, thereby providing asymmetric monoalkyl and monoalkylthienyl thienoacenes. Alkyl-substituted ATT (CnATT, n = 6, 8, 10, 12) has characteristics of a p-type field-effect transistor (FET), with mobility on the order of 0.01 cm2 V–1 s–1, which is the same as ATT. Conversely, alkylthienyl-substituted ATT (CnTATT, n = 6, 8, 10, 12) exhibits FET mobility of 0.15–1.9 cm2 V–1 s–1, which is up to 2 orders of magnitude greater than that of ATT and CnATT. Moreover, CnTATT forms crystalline thin films both by spin coating and drop casting, and C8TATT in particular exhibits a mobility of up to 1.6 cm2 V–1 s–1 in the drop-cast film. X-ray diffraction patterns of CnTATT thin films indicate that the molecules become oriented edge-on at the substrate surface with a highly ordered structure in the in-plane direction. Accor...

Two novel bent-shaped thienoacenes, naphtho[2,3-b]naphtho[2′,3′:4,5]thieno[3,2-d]thiophene (bent-DNTT) and anthra[2,3-b]anthra[2′,3′:4,5]thieno[3,2-d]thiophene (bent-DATT) were synthesized from thieno[2,3-b]thiophene and their corresponding aromatic anhydrides by three steps: Friedel–Crafts acylation, acid-promoted cyclization, and reductive aromatization. The structural curvature improved the solubility of these thienoacenes in organic solvents. The bent-DNTT based FET device was fabricated by the spin-coating method. The device exhibited p-type characteristics with a mobility of 5.1 × 10−5 cm2 V−1 s−1. Its thin-film structure was fully characterized as an edge-on orientation with large intermolecular orbital coupling.

9,9′-Bifluorenylidene (BFN) derivatives, in which the two fluorene moieties are connected via a CC double bond at the 9-position, are expected to show singlet fission (SF) character in organic photovoltaics (OPVs). Due to steric repulsion between the hydrogen atoms at the 1,8- and 1′,8′-positions, the two fluorene planes of BFN are twisted by 31° with respect to each other. DFT calculations suggest that this deviation from coplanarity lowers the T1 energy level of BFN to approximately half that of S1. We synthesized a molecular alkylbithiophene-substituted BFN and a copolymer of diketopyrrolopyrrole and BFN. The optoelectronic properties of these compounds were investigated, and OPV devices using these BFNs as a p-type material were fabricated. The device composed of the polymeric BFN derivative achieved a power conversion efficiency of 4.9%. The observed negative dependence of the photocurrent on the magnetic field suggested that the triplet excitons of the molecular BFN derivatives contribute to the photocurrent in these OPV devices.

Mellitic triimide derivatives with N-benzyl groups form conformations with concave cavities, that are capable of including aromatic molecules such as benzene, nitrobenzene, etc. In addition, they act as supramolecular gelators, which enable the detection of aromatic molecules as a gel-sol phase transition.

We evaluated the efficacy of gonadotropin-releasing hormone agonist (GnRHa) therapy for improving the myometrial thickness in women with thin (less than 1 cm) uterine walls, a contraindication for microwave endometrial ablation (MEA). The normal myometrium thickness was 0.5 cm, 0.7 cm and 0.9 cm. After the third GnRHa dose, the myometrial thickness increased to over 1 cm in all the three patients, and all were able to undergo MEA. The VAS score for menorrhagia improved in all the cases. The patient satisfaction levels were 10 in 2 of the 3 patients, and 5 in the other. There was no symptom recurrence, and no adjuvant therapy was administered. GnRHa therapy in women with submucous leiomyomata and a myometrial thickness of less than 1 cm could effectively thicken the myometrium, allowing for the use of MEA.