The spin sublevel dynamics of the excited triplet state in thermally activated delayed fluorescence (TADF) molecules have not been investigated for high-intensity organic light-emitting diode materials. Understanding mechanism intersystem crossing (ISC) is thus important designing novel TADF We report first study on ISC lowest from singlet with charge-transfer (CT) character different external quantum efficiencies (EQEs) using time-resolved electron paramagnetic resonance methods. Analysis...

Luminescent radicals are an emerging class of materials that exhibit unique photofunctions not found in closed-shell molecules due to their open-shell electronic structure. Particularly promising which radical's spin and luminescence correlated; for example, when a magnetic field can affect (i.e., magnetoluminescence, ML). These could be useful the new science photonics. However, previous observations ML have been limited systems randomly doped host crystals or polymerized through metal...

Magnetic field effects (MFEs) on singlet fission were studied by observing fluorescence from organic crystal of 1,6-diphenyl-1,3,5-hexatriene under magnetic fields up to 5 T. We found anomalous MFE dips at higher than 2 T, in addition the known MFEs which saturated around 1 The observed results analyzed using stochastic Liouville equation (SLE) a distance-dependent exchange interaction (J) triplet pair, hopping triplet, and geminate fusion contacted pair incorporated. SLE analysis revealed...

Triarylamine-substituted benzimidazoliums (BI+-PhNAr2), new electron donor-acceptor dyad molecules, were synthesized. Their photocatalytic properties for reductive organic transformations explored using absorption and fluorescence spectroscopy, redox potential determinations, density functional theory calculations, transient reduction reactions of selected substrates. The results show that irradiation BI+-PhNAr2 promotes photoinduced intramolecular transfer to form a long-lived (∼300 μs)...

Grinding a mixture of 3-chlorobiphenyl (BP-Cl) and CaO with or without the addition quartz was conducted in air by planetary ball mill to investigate mechanochemical dechlorination BP-Cl. The dechlorinating reaction proceeds an increase grinding time, over 99% BP-Cl is decomposed at 360 min. Washing ground sample different solvents results products. Addition facilitates efficiency, especially case high weight ratio CaO.

Reactions of [FeII(CN)2(bpy)2] and [FeIII(CN)2(bpy)2](PF6) with [CuII(bpy)(CH3OH)2](PF6)2 in methanol yielded cyanide-bridged cyclic tetranuclear complexes [FeII2CuII2(μ-CN)4(bpy)6](PF6)4·2H2O·4CHCl3 (1) [FeIII2CuII2(μ-CN)4(bpy)6](PF6)6·4CH3CN·2CHCl3 (2), respectively. In the squares 1 2, Fe2+/3+ (low-spin) Cu2+ ions are alternately bridged by cyanide ions, carbon atoms which coordinate to iron ions. Variable-temperature magnetic susceptibility studies revealed that magnetically isolated....

Benzimidazolium naphthoxide (−ONap-BI+) was first synthesized and utilized as an unprecedented betaine photoredox catalyst. Photoexcited state of –ONap-BI+ generated by visible light irradiation catalyzes the reductive deiodination well desulfonylation reactions in which 1,3-dimethyl-2-phenylbenzimidazoline (Ph-BIH) cooperates with electron hydrogen atom donor. Significant solvent effects on reaction progress were discovered, specific solvation toward imidazolium moieties proposed.

A visible light promoted process for desulfonylation of N-sulfonylamides and -amines has been developed, in which 1,3-dimethyl-2-hydroxynaphthylbenzimidazoline (HONap-BIH) serves as a absorbing, electron hydrogen atom donor, household white light-emitting diode source. The transforms various N-sulfonylamide -amine substrates to desulfonylated products moderate excellent yields. observation that the fluorescence 1-methyl-2-naphthoxy anion is efficiently quenched by suggests mechanism...

Photon upconversion via triplet-triplet annihilation (TTA-UC) is well-known as a photophysical process that converts low-energy light into higher-energy light. This has drawn attention for its potential in various fields including light-emitting device, power genera-tion, and medical applications. To promote these societal applications, it desirable to develop TTA-UC materials exhibit high ener-gy conversion efficiency. For this, TTA emitters with large rate constants (kTTA) are required....

Singlet fission, which may increase the energy conversion efficiency of solar cells, proceeds via multiple spin levels a triplet pair. To clarify spin-related elementary processes pair, we measured magnetoluminescence effect fluorescence rubrene, in form orthorhombic polycrystalline powder, range ±300 mT at room temperature. Model simulations using density matrix method were performed to elucidate how features depend on pair dynamics. Simulations observed field dependence revealed an...

The effect of the solvent viscosity dependence time-resolved magnetoluminescence (ML) on delayed fluorescence 9,10-diphenylanthracene (DPA) sensitized by platinum octaethylporphyrin has clarified structure and dynamics triplet-triplet pair (TT), i.e., transition state triplet fusion. Phase inversion ML with time provides evidence for recycle excited DPA in electron spin-relaxation random molecular rotation causes intersystem crossing among different spin states allows (3,5)TT to engage...

Abstract For the first time, we detected paramagnetic products generated during grinding of 3-chlorobiphenyl (BP-Cl) with calcium oxide (CaO) nanoparticles by a ball mill method, which is one promising ways to detoxify hazardous chlorinated organic compounds. Those were assigned oxygen-centered aromatic radicals coming from BP-Cl and trapped electrons in oxygen vacancies on surfaces CaO reactants using high-frequency pulsed electron resonance spectroscopies. The observed good correlation...

A high-frequency (95 GHz) and conventional-frequency (9.3 pulsed electron paramagnetic resonance electron-nuclear double (ENDOR) study is reported on the deep boron acceptor in $6H$-SiC. The results support a model which consists of silicon position with an adjacent carbon vacancy. vacancy combines along hexagonal $c$ axis. It concluded that 70--90% spin density resides dangling bonds surrounding another 9% neighboring atoms. spin-density distribution more localized than case shallow as...

We have studied the magnetic field effects (MFEs) on charge-transfer fluorescence and transient photocurrent of a 1,2,4,5-tetracyanobenzene-doped poly(N-vinylcarbazole) film, which reflect recombination escape yields carriers, respectively. The yield dependence external (B) clearly shows two types MFEs, growth with increasing B due to hyperfine mechanism (HFM) negative dip level-crossing (LCM). On other hand, indicates complementary MFEs sharp decrease in then positive dip. Simultaneous...

An orthogonal arrangement of imino nitroxide ligands in Cu(I) and Ag(I) complexes results propagation an intramolecular ferromagnetic interaction between the coordinated nitroxides through these diamagnetic ions. Reaction [Cu(I)(CH(3)CN)(4)](PF(6)) Ag(I)(PF(6)) with ethanol solution gave [Cu(I)(immepy)(2)](PF(6)) (1) [Ag(I)(impy)(2)](PF(6)) (2), respectively (immepy = 2-(2-(6-methylpyridyl))-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-1-oxy impy...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSpin Polarization Conservation during Intramolecular Triplet-Triplet Energy Transfer Studied by Time-Resolved EPR SpectroscopyKimio Akiyama, Shozo Tero-Kubota, Tadaaki Ikoma, and Yusaku IkegamiCite this: J. Am. Chem. Soc. 1994, 116, 12, 5324–5327Publication Date (Print):June 1, 1994Publication History Published online1 May 2002Published inissue 1 June 1994https://doi.org/10.1021/ja00091a042RIGHTS & PERMISSIONSArticle...

By using MO calculations based on DFT, absorption, and fluorescence spectroscopy, we have comprehensively studied the low-lying excited singlet states of alpha,omega-diphenylpolyynes (DPY) having 1-6 triple bonds. The a(g) vibrational modes C(triple bond)C stretching phenyl ring motion were observed in spectra diphenylacetylene 1,4-diphenylbutadiyne. On other hand, long DPY with triple-bond number (N) more than two, symmetry disappeared b(1g) twisting (approximately 400 cm(-1)) C-H bending...

N,N-Di(6-azulenyl)-p-toluidine (1a) and N,N,N',N'-tetra(6-azulenyl)-p-phenylenediamine (2a) their derivatives with 1,3-bis(ethoxycarbonyl) substituents on each 6-azulenyl group (1b 2b) were prepared by Pd-catalyzed amine azulenylation characterized as a study into new aromatic amines for multistage amphoteric redox materials. The behavior of compound was cyclic voltammetry. These compounds undergo facile reduction to stable anion radicals dianion diradicals owing the resonance stabilization...