Radical C-Glycosylation Using Photoexcitable Unprotected Glycosyl Borate.

We have developed radical C-glycosylation using photoexcitable unprotected glycosyl borate. The direct excitation of glycosyl borate under visible light irradiation enabled the generation of anomeric radical without any photoredox catalysts. The in situ generated anomeric radical was applicable to the radical addition such as Giese-type addition and Minisci-type reaction to introduce alkyl and heteroaryl groups at the anomeric position.

Ocean-wide comparisons of mesopelagic planktonic community structures.

For decades, marine plankton have been investigated for their capacity to modulate biogeochemical cycles and provide fishery resources. Between the sunlit (epipelagic) layer and the deep dark waters, lies a vast and heterogeneous part of the ocean: the mesopelagic zone. How plankton composition is shaped by environment has been well-explored in the epipelagic but much less in the mesopelagic ocean.

Conformational, Host, and Vibrational Effects Giving Rise to Dynamic TADF Behavior in the Through-Space Charge Transfer, Triptycene Bridged Acridine-Triazine Donor Acceptor TADF Molecule .

We present a joint experimental and theoretical study of the through-space charge transfer (CT) TADF molecule . The measured fluorescence has a singular Gaussian line shape but two decay components, coming from two distinct molecular CT conformers, energetically only 20 meV apart. We determined the intersystem crossing rate (1 × 10 s) to be 1 order of magnitude faster than radiative decay, and prompt emission (PF) is therefore quenched within 30 ns, leaving delayed fluorescence (DF) observable from 30 ns onward as the measured reverse intersystem crossing (rISC) rate is >1 × 10 s, yielding a DF/PF ratio >98%.

Split luciferase-based estimation of cytosolic cargo concentration delivered intracellularly via attenuated cationic amphiphilic lytic peptides.

Intracellular delivery of biomacromolecules is challenging as these molecules are taken up by cells and encapsulated into vesicular compartments called endosomes, and the fraction of molecules that are translocated to the cytosol are particularly important to obtain desired biological responses. This study aimed to estimate the cytosolic concentrations of intracellularly delivered peptides and proteins to aid the design of novel and effective biopharmaceutical delivery systems. To this end, we employed the split NanoLuc luciferase system, using the 11-residue HiBiT peptide segment as a probe for the delivered molecules in cells expressing the complementary LgBiT protein segment.

Acceleration of Reverse Intersystem Crossing using Different Types of Charge Transfer States.

There is a need to boost the rate constant of reverse intersystem crossing (k ) in thermally activated delayed fluorescence (TADF) materials for applications to organic light-emitting diodes. Recently, energy level matching of the locally excited state (LE) and charge transfer state (CT) has been reported to enhance k . In this study, we conceptually demonstrate that k can be improved even between CT states without LE states, through the use of different types of CT states.

Recycled Utilization of a Nanoporous Au Electrode for Reduced Fabrication Cost of Perovskite Solar Cells.

Perovskite solar cells (PSCs) using metal electrodes have been regarded as promising candidates for next-generation photovoltaic devices because of their high efficiency, low fabrication temperature, and low cost potential. However, the complicated and rigorous thermal deposition process of metal contact electrodes remains a challenging issue for reducing the energy pay-back period in commercial PSCs, as the ubiquitous one-time use of a contact electrode wastes limited resources and pollutes the environment. Here, a nanoporous Au film electrode fabricated by a simple dry transfer process is introduced to replace the thermally evaporated Au electrode in PSCs.

Experimental and Theoretical Examination of the Radical Cations Obtained from the Chemical and Electrochemical Oxidation of 5-Aminothiazoles.

Chemical or electrochemical one-electron oxidation of 5--arylaminothiazoles was found to afford stable radical cations. For chemical oxidation, 1 equivalent of [(4-BrCH)N][SbCl] (Magic Blue, MB) was added to CHCl solutions of the thiazoles, and the thus-obtained radicals showed light absorption in the near-infrared region. Electrochemical oxidation also led to bathochromic shifts in the absorption bands, and the obtained spectra were similar to those derived from the chemically oxidized species.

Acid-Responsive Absorption and Emission of 5--Arylaminothiazoles: Emission of White Light from a Single Fluorescent Dye and a Lewis Acid.

Solutions of 5--arylaminothiazoles containing pyridyl groups exhibited clear halochromism and halofluorism upon addition of Brønsted and Lewis acids. The addition of triflic acid to solutions of 5--arylaminothiazoles in EtO induced bathochromic shifts of the absorption and emission bands. DFT calculations suggested that the spectral changes arise from the protonation of the pyridyl group of the thiazoles in EtO.

Acid-Responsive Absorption and Emission of 5--Arylaminothiazoles: Emission of White Light from a Single Fluorescent Dye and a Lewis Acid.

10.1002/open.201600059.

PNP-Pincer-Type Phosphaalkene Complexes of Late Transition Metals.

This account summarizes our recent studies on PNP-pincer-type phosphaalkene complexes. Phosphaalkenes with a P=C bond possess an extremely low-lying π* orbital and have a marked tendency to engage in strong π back-bonding with transition metals. This particular ligand property provides PNP-pincer complexes with unique structures and reactivities.

(13)C/(15)N-Enriched l-Dopa as a Triple-Resonance NMR Probe to Monitor Neurotransmitter Dopamine in the Brain and Liver Extracts of Mice.

In an attempt to monitor μm-level trace constituents, we applied here (1)H-{(13)C-(15)N} triple-resonance nuclear magnetic resonance (NMR) to (13)C/(15)N-enriched l-Dopa as the inevitable precursor of the neurotransmitter dopamine in the brain. The perfect selectivity (to render endogenous components silent) and μm-level sensitivity (700 MHz spectrometer equipped with a cryogenic probe) of triple-resonance allowed the unambiguous and quantitative metabolic and pharmacokinetic analyses of administered l-Dopa/dopamine in the brain and liver of mice. The level of dopamine generated in the brain (within the range 7-76 μm, which covers the typical stimulated level of ∼30 μm) could be clearly monitored ex vivo, but was slightly short of the detection limit of a 7 T MR machine for small animals.

Triarylboron-Based Fluorescent Organic Light-Emitting Diodes with External Quantum Efficiencies Exceeding 20 .

Triarylboron compounds have attracted much attention, and found wide use as functional materials because of their electron-accepting properties arising from the vacant p orbitals on the boron atoms. In this study, we design and synthesize new donor-acceptor triarylboron emitters that show thermally activated delayed fluorescence. These emitters display sky-blue to green emission and high photoluminescence quantum yields of 87-100 % in host matrices.

Graph mining: procedure, application to drug discovery and recent advances.

Combinatorial chemistry has generated chemical libraries and databases with a huge number of chemical compounds, which include prospective drugs. Chemical structures of compounds can be molecular graphs, to which a variety of graph-based techniques in computer science, specifically graph mining, can be applied. The most basic way for analyzing molecular graphs is using structural fragments, so-called subgraphs in graph theory.