Mixed-Metal Ce-Zr-Mn Clusters as Photo-Catalysts for Decarboxylative Functionalization of Carboxylic Acids.

Decarboxylative hydrazination of carboxylic acids was achieved using a 1:5:2 ratio of three metal salts, Ce(OBu), Zr(OBu), and Mn(OAc), as a catalyst under visible light irradiation. The catalytic activity, compared with our previously developed Ce cluster photo-catalysts, was enhanced by the formation of single cerium-incorporated hexanuclear mixed-metal clusters containing a [CeZrO(OH)] core. The manganese salts further accelerated the overall reaction rate (10 times faster reaction rate with the manganese salt than that of the manganese-free conditions).

A Luminescent Stable Triarylmethyl Diradical with an Axially Chiral Spacer.

Two units of a highly stable luminescent triarylmethyl radical (PyBTM) were bridged using a chiral octahydrobinaphthyl moiety, resulting in a diradical with sufficient stability to enable the measurement of its chiroptical properties. To synthesize this diradical, a novel boronic ester radical precursor, αH-PyBTM-B(Epin), was designed. The use of this precursor significantly improved the yield and streamlined the preparation of stable luminescent radical-substituted molecules.

Emission enhancement in a luminescent polychlorinated diphenylpyridylmethyl radical through coordination to silver(I).

A luminescent silver(I) complex containing a luminescent radical ligand was prepared for the first time. Coordination to Ag enhanced and red-shifted the radical-centered emission. This study demonstrates similar effects in the luminescence of the radical by complexation with group 11 d-metal ions.

Synthesis of Multisubstituted Cyclopentadiene Derivatives from 3,3-Disubstituted Cyclopropenes and Internal Alkynes Catalyzed by Low-Valent Niobium Complexes.

A low-valent niobium species generated from NbCl and 1-methyl-3,6-bis(trimethylsilyl)-1,4-cyclohexadiene (-Me-CHD) in combination with PPh catalyzed a [2+2+1]-cycloaddition reaction of 3,3-disubstituted cyclopropenes and 2 equiv of diaryl/dialkylalkynes, leading to isomeric mixtures of multisubstituted cyclopentadienes -. The initial catalyst activation process was a one-electron reduction of NbCl with -Me-CHD to provide [NbCl(μ-Cl) (L)] (L = PMePh (), L = PPh ()) in the presence of phosphine ligands. An NMR spectroscopic time course experiment using complex as the catalyst revealed an induction period for the product formation, corresponding to an additional one-electron reduction of by the substrates to give catalytically active η-alkyne complexes of NbCl.

Decarboxylative Alkylation of Carboxylic Acids with Easily Oxidizable Functional Groups Catalyzed by an Imidazole-Coordinated Fe Cluster under Visible Light Irradiation.

Decarboxylative alkylation of carboxylic acids with easily oxidizable functional groups such as phenol and indole functionalities was achieved using a catalytic amount of basic iron(III) acetate, Fe(OAc)(OH), in the presence of benzimidazole under 427 nm LED irradiation. Kinetic analyses of this catalytic reaction revealed that the reaction rate is first-order in alkenes and is linearly correlated with the light intensity; the faster reaction rate for the benzimidazole-ligated species was consistent with the increased absorbance in the visible light region. Wide functional group tolerance for the easily oxidizable groups is ascribed to the weak oxidation ability of the in situ-generated oxo-bridged iron clusters compared with other iron(III) species.

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.

Amplification of luminescence of stable radicals by coordination to NHC-gold(I) complex.

The luminescence of stable radicals can be enhanced by coordination to metal complexes. The 4% fluorescence quantum yield of (3,5-difluoro-4-pyridyl)bis(2,4,6-trichlorophenyl)methyl radical (FPyBTM) in dichloromethane was enhanced up to 36% by coordination to Au with -heterocyclic carbene ligand, which is a record for metal-radical complexes.

Expansion of Photostable Luminescent Radicals by Meta-Substitution.

Polychlorinated pyridyldiphenylmethyl radicals having substituents meta to the position bearing the carbon-centered radical (α-carbon) are synthesized. All of them are stable in ambient conditions in solutions and fluorescent in cyclohexane. The fluorescence of the radicals with bromo, phenyl, 4-chlorophenyl, or 2-pyridyl substituents are enhanced in chloroform, while the emission of the radicals with 2-thienyl or 2-furyl substituents are quenched in chloroform.

A ground-state-dominated magnetic field effect on the luminescence of stable organic radicals.

Organic radicals are an emerging class of luminophores possessing multiplet spin states and potentially showing spin-luminescence correlated properties. We investigated the mechanism of recently reported magnetic field sensitivity in the emission of a photostable luminescent radical, (3,5-dichloro-4-pyridyl)bis(2,4,6-trichlorophenyl)methyl radical (PyBTM) doped into host -PyBTM molecular crystals. The magnetic field (0-14 T), temperature (4.

Radical-Based Coordination Polymers as a Platform for Magnetoluminescence.

Spin-correlated electronic and magnetic properties of organic radicals have been developed, but luminescence properties, based on interplay with spins, have rarely been reported. The effect of magnetic fields on luminescence (i.e.

An Open-shell, Luminescent, Two-Dimensional Coordination Polymer with a Honeycomb Lattice and Triangular Organic Radical.

The use of organic radicals as building blocks is an effective approach to the production of open-shell coordination polymers (CPs). Two-dimensional (2D) CPs with honeycomb spin-lattices have attracted attention because of the unique electronic structures and physical properties afforded by their structural topology. However, radical-based CPs with honeycomb spin-lattices tend to have low chemical stability or poor crystallinity, and thus novel systems with high crystallinity and persistence are in strong demand.

Electric dipole induced bulk ferromagnetism in dimer Mott molecular compounds.

Magnetic properties of Mott-Hubbard systems are generally dominated by strong antiferromagnetic interactions produced by the Coulomb repulsion of electrons. Although theoretical possibility of a ferromagnetic ground state has been suggested by Nagaoka and Penn as single-hole doping in a Mott insulator, experimental realization has not been reported more than half century. We report the first experimental possibility of such ferromagnetism in a molecular Mott insulator with an extremely light and homogeneous hole-doping in π-electron layers induced by net polarization of counterions.

Identifying the Factors Governing the Early-Stage Degradation of Cu-Chabazite Zeolite for NH-SCR.

To understand the degradation mechanism of the copper-ion-exchanged SSZ-13 (Cu-SSZ-13) is of high significance for rationally designing a zeolitic catalyst for ammonia-selective catalytic reduction of NO (NH-SCR). In this work, we focused on an Al-rich Cu-SSZ-13 and studied its structural degradation under hydrothermal conditions through a set of characterization techniques, including in situ X-ray diffraction (XRD), pair distribution function analysis and transmission electron microscopy-energy dispersive X-ray analysis (TEM-EDX). The results indicated that the chabazite structure tends to contract in the direction upon hydrothermal treatment and consequently leads to the collapse of the four-membered ring.

Luminescent Radical-Excimer: Excited-State Dynamics of Luminescent Radicals in Doped Host Crystals.

The excited-state dynamics of the photostable luminescent organic radical (3,5-dichloro-4-pyridyl)bis(2,4,6-trichlorophenyl)methyl (PyBTM) doped in a host crystal was investigated by using optically detected magnetic resonance (ODMR) and time-resolved emission spectroscopies. In the radical system, the unpaired electron can be used as the probe for studying the electronic state and its dynamics. The mixed crystal with a high concentration of the radical showed excimer emission, together with the monomer emission.

Magnetoluminescence in a Photostable, Brightly Luminescent Organic Radical in a Rigid Environment.

We investigated the emission properties of a photostable luminescent organic radical, (3,5-dichloro-4-pyridyl)bis(2,4,6-trichlorophenyl)methyl radical (PyBTM), doped into host molecular crystals. The 0.05 wt %-doped crystals displayed luminescence attributed to a PyBTM monomer with a room-temperature emission quantum yield of 89 %, which is exceptionally high among organic radicals.