Synthesis of Azadioxa-Planar Triphenylboranes Bridged by Aryl- and Alkylimino Groups and Their Photophysical Properties.

Heteroatom-bridged planar triphenylboranes, in which the three phenyl groups are bridged at the ortho positions by heteroatoms, are attracting growing attention as one of the heteroatom-containing π-conjugated molecules. Herein, we developed the synthetic method of planar triphenylboranes bridged by two oxygen atoms and one nitrogen atom, and the substituent on the nitrogen atom is derived into various aryl and alkyl groups. A key intermediate bearing an imino group (-NH-) was synthesized from a bis-triflate precursor bridged by two oxo groups via a nucleophilic aromatic substitution reaction of benzyl amine and following debenzylation. The X-ray crystallographic analysis revealed that the compound exhibits a planar molecular structure which can form a one-dimensionally π-stacked structure. The photophysical and density functional theory studies revealed that their highest occupied molecular orbitals and lowest unoccupied molecular orbitals (LUMOs) are originated from the triphenylborane moiety, while introducing strong electron-withdrawing groups such as the 4-cyanophenyl group on the nitrogen atom can induce the localization of the LUMO at the aryl groups instead of the triphenylborane moiety.

Fluorescent Organic π-Radicals Stabilized with Boron: Featuring a SOMO-LUMO Electronic Transition.

We report on the fluorescence properties of a new class of emissive and stable π-radicals that contain a boron atom at a position distant from the radical center. A fully planarized derivative exhibited an intense red fluorescence with high fluorescence quantum yields (ΦF >0.67) even in polar solvents. To elucidate the origin of this phenomenon, we synthesized another boron-stabilized radical that contains a bulky aryl group on the boron atom. A comparison of these derivatives, as well as with conventional donor-π-acceptor (D-π-A)-type emissive π-radicals, unveiled several characteristic features in their photophysical properties. A theoretical analysis revealed that the SOMO-LUMO electronic transition generates an emissive D1 state. Unlike conventional D-π-A-type π-radicals, this state does not undergo significant structural relaxation. The boron-stabilized π-radicals demonstrated promising potential for organic light-emitting diodes as an emitting material.

Acyclic, Linear Oligo-meta-phenylenes as Multipotent Base Materials for Highly Efficient Single-layer Organic Light-emitting Devices.

Oligo-meta-phenylenes have been designed and synthesized as multipotent base materials of single-layer organic light-emitting devices. Simple molecular structures of oligo-meta-phenylenes composed of linear phenylene arrays benefited from the wealth of modern reactions available for biaryl couplings and were concisely synthesized in a series. Structure-performance relationship studies with the first seven congeners revealed key features important for the multipotent materials in single-layer devices. As a result, highly efficient phosphorescent electroluminescence was made possible in a highly simplified device architecture comprising one-region, single-layer configurations. Detailed investigations with hole-only devices disclosed that the hole mobility was effectively retarded by potent materials, which should facilitate hole/electron recombination for electroluminescence.

Periphery Design of Macrocyclic Materials for Organic Light-Emitting Devices with a Blue Phosphorescent Emitter.

Cyclo- meta-phenylenes were modified with trifluoromethyl groups at their periphery to create host materials suitable for use in blue phosphorescent organic light-emitting devices. The periphery design resulted in molecules with high triplet-state energies, which were required to support the blue emission from Ir phosphors. As a result, an external quantum efficiency of 9.9% was achieved. The most successful host, a pentameric congener, preferred CF-π/CH-π interactions in its crystalline packings, which could be beneficial for the host performance.

Investigation of the Lewis acidic behaviour of an oxygen-bridged planarized triphenylborane toward amines and the properties of their Lewis acid-base adducts.

Lewis acid behavior of an oxygen-bridged triphenylborane (1) to amines and the properties of Lewis acid-base adducts of 1 with amines have been investigated. UV-vis titration and 11B NMR experiments showed the formation of Lewis acid-base adducts of 1 with pyridine, DMAP, quinuclidine, and DABCO, respectively (1·amine). X-ray crystallographic analysis revealed that the planar shape of 1 was converted to a bowl shape by the formation of 1·amine. Interestingly, 1·quinuclidine, 12·DABCO, and 1·DABCO exhibited dual emissions. Excitation spectra and photoluminescence decay time measurements suggest that the dual emissions were ascribed to two excited species, i.e., [1·amine]* and [1]* generated by photodissociation in the excited states.

Efficient Blue Electroluminescence from a Single-layer Organic Device Composed Solely of Hydrocarbons.

An interesting physical phenomenon, electroluminescence, that was originally observed with a hydrocarbon molecule has recently been developed into highly efficient organic light-emitting devices. These modern devices have evolved through the development of multi-element molecular materials for specific roles, and hydrocarbon devices have been left unexplored. In this study, we report an efficient organic light-emitting device composed solely of hydrocarbon materials. The electroluminescence was achieved in the blue region by efficient fluorescence and charge recombination within a simple single-layer architecture of macrocyclic aromatic hydrocarbons. This study may stimulate further studies on hydrocarbons to uncover their full potential as electronic materials.

The first synthesis and X-ray crystallographic analysis of an oxygen-bridged planarized triphenylborane.

An oxygen-bridged planarized triphenylborane has been successfully synthesized. X-ray crystallographic analysis revealed that the molecule has a complete planarized structure and the shortest C-B bonds among the triarylboranes synthesized to date.

Comparison of nafamostat mesilate and unfractionated heparin as anticoagulants during continuous renal replacement therapy.

PURPOSE: Nafamostat mesilate (NM) can be used as a regional anticoagulant for continuous renal replacement therapy (CRRT). The primary aim of this study was to assess the association of the use of NM with risk of bleeding complications and compare it with the use of unfractionated heparin (UFH). METHODS: We conducted a single-center retrospective observational study. We included adult patients who required CRRT in our intensive care unit from 2011 to 2013. The primary outcome was the risk of bleeding complications during CRRT and the secondary outcome was filter life for the first filter of CRRT. RESULTS: We included 101 patients (76 with NM, 25 with UFH). Among the 101 patients, use of NM tended to be associated with lower risk of bleeding complications (6.6% vs. 16%; odds ratio, 0.37; p = 0.16). Propensity score matching generated 30 patients with NM and 15 patients with UFH with well-balanced baseline characteristics. Among the propensity score-matched cohorts, use of NM was significantly associated with decreased risk of bleeding complications (3.3% vs. 27%; odds ratio, 0.09; p = 0.04). In multivariate logistic analysis using the inverse probability of treatment weighting for sensitive analysis, the use of NM was independently associated with reduced risk of bleeding complications (p = 0.02). The median filter life was not significantly different for patients with NM and patients with UFH (25.5 hours vs. 30.5 hours, p = 0.16). CONCLUSIONS: In our retrospective analysis, the use of NM as an anticoagulant during CRRT was associated with decreased incidence of bleeding complications compared with the use of UFH.

Modular Synthesis of Aromatic Hydrocarbon Macrocycles for Simplified, Single-Layer Organic Light-Emitting Devices.

A method for the modular synthesis of aromatic hydrocarbon macrocycles has been developed for base materials in single-layer organic light-emitting devices. The method with Ir-catalyzed direct C-H borylation and Suzuki-Miyaura coupling was concise and scalable, which allowed for a gram-scale preparation of aromatic hydrocarbon macrocycles that have bulky substituents at the periphery. The new arylated hydrocarbon macrocycles enabled a quantitative electro-optical conversion in organic light-emitting devices with a phosphorescent emitter, which is, notably, in a single-layer architecture consisting of two regions of doped and undoped materials. The highest external quantum efficiencies reached 24.8%, surpassing those of previous hydrocarbon base materials.

Aromatic hydrocarbon macrocycles for highly efficient organic light-emitting devices with single-layer architectures.

A modern electrophosphorescent organic light-emitting device (OLED) achieves quantitative electro-optical conversion by using multiple layers of molecular materials designed through role allotment for independent and specific functions. A unique, potentially innovative device architecture, i.e., a single-layer phosphorescent OLED, is currently being developed by designing multirole base materials via a structural combination of multiple functional components in single molecules. The multirole molecules, however, inevitably require multiple processes to synthesize their multiple components and, moreover, to assemble these components synthetically into one molecule. We herein show that the multirole base material for a highly efficient single-layer phosphorescent OLED can be designed and synthesized with a single, very simple aromatic hydrocarbon component of toluene merely through a one-pot macrocyclization. Without requiring the assembly tasks at the synthesis stage, the molecular design allows for a concise one-pot synthesis of, and a quantitative electro-optical conversion in, the single-layer device architecture with a single-component base material.

Cyclo-meta-phenylene revisited: nickel-mediated synthesis, molecular structures, and device applications.

From a one-pot nickel-mediated Yamamoto-type coupling reaction of m-dibromobenzene, five congeners of [n]cyclo-meta-phenylenes were synthesized and fully characterized. The [n]cyclo-meta-phenylenes possessed a commonly shared arylene unit and intermolecular contacts but varied in packing structures in the crystalline solid state. Columnar assembly of larger congeners yielded nanoporous crystals with carbonaceous walls to capture minor protic or aliphatic solvent molecules. The concise and scalable synthesis allowed exploration of the macrocyclic hydrocarbons as bipolar charge carrier transport materials in organic light-emitting diode devices.

Phosphorescent cyclometalated complexes for efficient blue organic light-emitting diodes.

Phosphorescent emitters are extremely important for efficient organic light-emitting diodes (OLEDs), which attract significant attention. Phosphorescent emitters, which have a high phosphorescence quantum yield at room temperature, typically contain a heavy metal such as iridium and have been reported to emit blue, green and red light. In particular, the blue cyclometalated complexes with high efficiency and high stability are being developed. In this review, we focus on blue cyclometalated complexes. Recent progress of computational analysis necessary to design a cyclometalated complex is introduced. The prediction of the radiative transition is indispensable to get an emissive cyclometalated complex. We summarize four methods to control phosphorescence peak of the cyclometalated complex: (i) substituent effect on ligands, (ii) effects of ancillary ligands on heteroleptic complexes, (iii) design of the ligand skeleton, and (iv) selection of the central metal. It is considered that novel ligand skeletons would be important to achieve both a high efficiency and long lifetime in the blue OLEDs. Moreover, the combination of an emitter and a host is important as well as the emitter itself. According to the dependences on the combination of an emitter and a host, the control of exciton density of the triplet is necessary to achieve both a high efficiency and a long lifetime, because the annihilations of the triplet state cause exciton quenching and material deterioration.

CIBIC Plus-J Assessment Using a Videotaped Method in Alzheimer's Disease Patients.

BACKGROUND/AIMS: CIBIC plus-J is the Japanese language version equivalent to CIBIC plus. Variability of CIBIC plus-J arises among raters in accordance with their experience and their memories of patients' conditions at baseline. Therefore, in a multicenter trial of Alzheimer's disease, CIBIC plus-J interviews with Alzheimer's disease patients were videotaped, and the tapes were assessed by central raters as a means to improve the reliability of CIBIC plus-J assessment. METHODS: Two of eight central raters were randomly selected and independently assessed the CIBIC plus-J of each patient. RESULTS: CIBIC plus-J of 41 patients was assessed. The agreement rate between the two raters was 46.3% (19/41), when two raters assessed the CIBIC plus-J of the same patient. However, when considering disagreement between adjacent points as 'agree', the agreement rate was 97.6% (40/41). Although the kappa coefficients contained coincidence, simple and quadratic weighted kappa coefficients [95% confidential interval (CI)] were 0.226 (0.066-0.386) and 0.633 (0.507-0.759), respectively, and when considering disagreement between adjacent points as 'agree', the agreement kappa was 0.896 (0.752-1.041). The interclass coefficient from the two-way layout model was 0.639. CONCLUSION: The reliability of the CIBIC plus-J assessment with the videotaped method was acceptable.

Synthesis of disilanyl double-pillared bisdibenzofuran with a high triplet energy.

A double-pillaring strategy for the synthesis of silacyclophanes has been applied to dibenzofuran to create a new cyclophane molecule that links two dibenzofuran molecules through σ(SiSi)-π conjugation. The performance of disilanyl double-pillared dibenzofuran [(Si)DPBD(O)] in green phosphorescent organic light-emitting diode (OLED) devices was evaluated as both a carrier-transport material and a host material for an Ir-based phosphorescent emitter.

Constructing partial models of cells.

Understanding the origin of life requires knowledge not only of the origin of biological molecules such as amino acids, nucleotides and their polymers, but also the manner in which those molecules are integrated into the organized systems that characterize cellular life. In this article, we introduce a constructive approach to understand how biological molecules can be arranged to achieve a higher-order biological function: replication of genetic information.

Compartmentalization in a water-in-oil emulsion repressed the spontaneous amplification of RNA by Q beta replicase.

During RNA replication mediated by Qbeta replicase, self-replicating RNAs (RQ RNAs) are amplified without the addition of template RNA. This undesired amplification makes the study of target RNA replication difficult, especially for long RNA such as genomic RNA of Qbeta phage. This perhaps is one of the reasons why the precise rate of genomic RNA replication in the presence of host factor Hfq has not been reported in vitro. Here, we report a method to repress RQ RNA amplification by compartmentalization of the reaction using a water-in-oil emulsion but maintaining the activity of Qbeta replicase. This method allowed us to amplify the phage Qbeta genome RNA exponentially without detectable amplification of RQ RNA. Furthermore, we found that the rate constant of genome RNA replication in the exponential phase at the optimum Hfq concentration was approximately 4.6 times larger than that of a previous report, close to in vivo data. This result indicates that the replication rate in vivo is largely explained by the presence of Hfq. This easy method paves the way for the study of genomic RNA replication without special care for the undesired RQ RNA amplification.

Chapter 2 - Detection and analysis of protein synthesis and RNA replication in giant liposomes.

In living cells, biochemical reaction systems are enclosed in small lipidic compartments. To experimentally simulate various biochemical reactions occurring in extant cells, giant liposomes are used to reconstruct an artificial model cell. We present methods for conducting a protein synthesis reaction, followed by the reaction catalyzed by the synthesized proteins inside liposomes, and for measurement of the in liposome reaction using a fluorescence-activated cell sorter (FACS). These techniques enable us to perform detailed analysis of the biochemical reactions occurring in the microcompartments, and have the potential to reveal the role of compartmentalization in cellular systems.

Quantitative analysis of the bacteriophage Qbeta infection cycle.

In this study, the infection cycle of bacteriophage Qbeta was investigated. Adsorption of bacteriophage Qbeta to Escherichia coli is explained in terms of a collision reaction, the rate constant of which was estimated to be 4x10(-10) ml/cells/min. In infected cells, approximately 130 molecules of beta-subunit and 2x10(5) molecules of coat protein were translated in 15 min. Replication of Qbeta RNA proceeded in 2 steps-an exponential phase until 20 min and a non-exponential phase after 30 min. Prior to the burst of infected cells, phage RNAs and coat proteins accumulated in the cells at an average of up to 2300 molecules and 5x10(5) molecules, respectively. An average of 90 infectious phage particles per infected cell was released during a single infection cycle up to 105 min.