Showing papers on "Benzophenone published in 2018"
TL;DR: The results showed that these three activation methods can remarkably enhance BP-3 removal efficiency and is a unique contribution to the systematic elucidation of BP- 3 removal by PS.
118 citations
TL;DR: Experimental and computational results now establish that a complex is formed between the two reagents, with the potassium ion providing the linkage, which markedly shifts the absorption spectrum to provide a tail in the visible light region.
Abstract: Long-standing controversial reports of electron transfer from KOtBu to benzophenone have been investigated and resolved. The mismatch in the oxidation potential of KOtBu (+0.10 V vs SCE in DMF) and the first reduction potential of benzophenone (of many values cited in the literature, the least negative value is −1.31 V vs SCE in DMF), preclude direct electron transfer. Experimental and computational results now establish that a complex is formed between the two reagents, with the potassium ion providing the linkage, which markedly shifts the absorption spectrum to provide a tail in the visible light region. Photoactivation at room temperature by irradiation at defined wavelength (365 or 400 nm), or even by winter daylight, leads to the development of the blue color of the potassium salt of benzophenone ketyl, whereas no reaction is observed when the reaction mixture is maintained in darkness. So, no electron transfer occurs in the ground state. However, when photoexcited, electron transfer occurs within a...
58 citations
TL;DR: In this article, a benzophenone azine based schiff base exhibiting AIE and ESIPT phenomenon has been synthesized and studied the photophysical behaviour towards detection of Al3+ ions.
Abstract: Benzophenone azine based schiff base exhibiting AIE and ESIPT phenomenon has been synthesised and studied the photophysical behaviour towards detection of Al3+ ions. The results showed that compound 2 exhibit feeble excited state intramolecular proton transfer emission in CH3CN and undergo aggregation induced emission in >70% H2O-CH3CN. The compound 2 shows significant hydrodynamic diameter change from 20 nm to 200 nm upon increasing the H2O volume ratio in CH3CN. Compound 2 shows colorimetric and “off-on” emission response for Al3+, with detection limit of 2.7 × 10−7 M in CH3OH. The association of compound 2 to Al3+ also causes restriction in intramolecular motion induced emission. The hydrodynamic diameter of compound 2 increases from 335 nm to 625 nm in the presence of Al3+ ion in CH3OH.
47 citations
TL;DR: This review will provide an overview of benzophenone moieties with medicinal aspects synthesized in the last 15 years and will cover the most potent molecule in each report.
Abstract: The benzophenone scaffold represents a ubiquitous structure in medicinal chemistry because it is found in several naturally occurring molecules which exhibit a variety of biological activities, such as anticancer, anti-inflammatory, antimicrobial, and antiviral. In addition, various synthetic benzophenone motifs are present in marketed drugs. They also represent important ingredients in perfumes and can act as photoinitiators. This review will provide an overview of benzophenone moieties with medicinal aspects synthesized in the last 15 years and will cover the most potent molecule in each report. In this review, only benzophenones with substitutions on their aryl rings, i.e. diphenyl ketone analogues, have been covered.
44 citations
TL;DR: It is indicated that BrC induced radical production may amount to an upper limit of 20 and 200 M day-1 of HO2 and organic radical respectively, which is greater or in the same order of magnitude as the internal radical production from other processes, previously estimated to be around 15 M per day.
Abstract: Atmospheric aerosol particles may contain light absorbing (brown carbon, BrC), triplet forming organic compounds that can sustain catalytic radical reactions and thus contribute to oxidative aerosol aging. We quantify UVA induced radical production initiated by imidazole-2-carboxaldehyde (IC), benzophenone (BPh). and 4-benzoylbenzoic acid (BBA) in the presence of the nonabsorbing organics citric acid (CA), shikimic acid (SA), and syringol (Syr) at varying mixing ratios. We observed a maximum HO2 release of 1013 molecules min-1 cm-2 at a mole ratio XBPh < 0.02 for BPh in CA. Mixtures of either IC or BBA with CA resulted in 1011-1012 molecules min-1 cm-2 of HO2 at mole ratios ( XIC and XBBA) between 0.01 and 0.15. HO2 release was affected by relative humidity ( RH) and film thickness suggesting coupled photochemical reaction and diffusion processes. Quantum yields of HO2 formed per absorbed photon for IC, BBA and BPh were between 10-7 and 5 × 10-5. The nonphotoactive organics, Syr and SA, increased HO2 production due to the reaction with the triplet excited species ensuing ketyl radical production. Rate coefficients of the triplet of IC with Syr and SA measured by laser flash photolysis experiments were kSyr = (9.4 ± 0.3) × 108 M-1 s-1 and kSA = (2.7 ± 0.5) × 107 M-1 s-1. A simple kinetic model was used to assess total HO2 and organic radical production in the condensed phase and to upscale to ambient aerosol, indicating that BrC induced radical production may amount to an upper limit of 20 and 200 M day-1 of HO2 and organic radical respectively, which is greater or in the same order of magnitude as the internal radical production from other processes, previously estimated to be around 15 M per day.
39 citations
TL;DR: This work is the first to report the integrated Paternò-Büchi reaction with LC-MS lipidomics for identification of lipid isomers and comprehensively evaluated the conditions of the PB reaction and screened benzophenone as a new PB reagent.
38 citations
TL;DR: In this paper, four twisted pure organic luminogens based on benzophenone and aromatic amines were synthesized and their photophysical properties were thoroughly investigated, and they exhibited crystallization-induced phosphorescence (CIP), giving bright fluorescence and phosphorescence dual emission in crystals.
32 citations
TL;DR: The spectroscopic evidence suggests that the preferred pathway for ISC is from the S1(nπ*) to the T2(ππ*) state, with the rate of internal conversion from T2(* to T1( nπ*) controlled by solvent quenching of excess vibrational energy.
Abstract: Solvation plays a critical role in various physicochemical and biological processes. Here, the rate of intersystem crossing (ISC) of benzophenone from its S1(nπ*) state to its triplet manifold of states is shown to be modified by hydrogen-bonding interactions with protic solvent molecules. We selectively photoexcite benzophenone with its carbonyl group either solvent coordinated or uncoordinated by tuning the excitation wavelength to the band center (λ = 340 nm) or the long-wavelength edge (λ = 380 nm) of its π* ← n absorption band. A combination of ultrafast absorption and Raman spectroscopy shows that the hydrogen-bonding interaction increases the time constant for ISC from <200 fs to 1.7 ± 0.2 ps for benzophenone in CH3OH. The spectroscopic evidence suggests that the preferred pathway for ISC is from the S1(nπ*) to the T2(ππ*) state, with the rate of internal conversion from T2(ππ*) to T1(nπ*) controlled by solvent quenching of excess vibrational energy.
24 citations
TL;DR: In this paper, a series of N,N-substituted benzophenone-based waterborne polyurethanes (WPUs) were synthesized by a facile polycondensation reaction, which exhibit both delayed fluorescence (DF) and RTP emission utilizing strong intramolecular charge-transfer states (CT states) to serve as a bridge between singlet and triplet states.
23 citations
TL;DR: The results expand the reduction capabilities of UIII complexes and demonstrate a strategy for isolating novel metal-stabilized radicals.
Abstract: Methyl benzoate, N,N-dimethylbenzamide, and benzophenone were reduced by UIII [N(SiMe3 )2 ]3 resulting in uranium(IV) products. Reduction of benzophenone lead to UIV [OC⋅Ph2 )][N(SiMe3 )2 ]3 , (1.1) which forms the dinuclear complex, [N(SiMe3 )2 ]3 UIV (OCPhPh-CPh2 O)UIV [N(SiMe3 )2 ]3 (1.2), through coupling of the ketyl radical species upon crystallization. Reaction of N,N-dimethylbenzamide with UIII [N(SiMe3 )2 ]3 resulted in UIV [OC⋅(Ph)(NMe2 )][N(SiMe3 )2 ]3 (2), a uranium(IV) compound and the first example of a charge-separated amide radical. In the case of methyl benzoate, the reduction resulted in UIV (OMe)[N(SiMe3 )2 ]3 (3) and benzaldehyde as the reduced organic fragment. Compound 2 showed the ability to act as a uranium(III) synthon in its reactivity with trimethylsilyl azide, a reaction that yielded UV (=NSiMe3 )[N(SiMe3 )2 ]3 . Additionally, 2 was reduced with potassium graphite resulting in [U(μ-O)[O=C(NMe2 )(Ph)][N(SiMe3 )2 ]2 ]2 (4), a dinuclear uranium compound bridged by oxo ligands. Reduction of 2 in the presence of 15-crown-5 afforded isolation of the mono-oxo compound, [(15-crown-5)2 K][UO[N(SiMe3 )2 ]3 ] (5). The results expand the reduction capabilities of UIII complexes and demonstrate a strategy for isolating novel metal-stabilized radicals.
21 citations
05 Oct 2018
TL;DR: A facile generation of organic solvents of anhydrous grade can be performed by distillation from sodium–benzophenone ketyl, which is prepared from commercial sodium dispersion and benzophenone.
Abstract: A facile generation of organic solvents of anhydrous grade can be performed by distillation from sodium–benzophenone ketyl, which is prepared from commercial sodium dispersion and benzophenone. The distilled tetrahydrofuran, diethyl ether, hexane, 1,2-dimethoxyethane, and 1,4-dioxane with water contents less than 10 ppm were obtained by a simple protocol. Safe treatment of the distillation residue also was simply achieved by the addition of methanol. The protocol suits for providing a small amount of an anhydrous solvent at the laboratory scale.
TL;DR: In this paper, photo-reactive poly(phosphoester)s (PPEs) forming surface-attached PPE-networks and hydrogels are presented.
TL;DR: A rare example of a stable charge-separated ketyl radical species is reported with ytterbium, and divalent thulium was observed to induce a reductive coupling at the ligand's central pyridine ring.
Abstract: The coordination and reactivity of simple iodide salts of low-valent f elements [YbI2, SmI2, TmI2, and UI3(THF)4, where THF = tetrahydrofuran] with iminophosphorane (R3P═NR′) ligands are reported. The studied chelates were observed to adapt their geometry and effectively bind divalent ytterbium and samarium centers, as well as the trivalent uranium cation. The reactivity of the ytterbium adducts with benzophenone was found to be dependent on the steric demand of the supporting iminophosphorane ligand. In particular, a rare example of a stable charge-separated ketyl radical species is reported with ytterbium. Additionally, divalent thulium was observed to induce a reductive coupling at the ligand’s central pyridine ring.
TL;DR: In this paper, the solubility of benzophenone in various pure solvents, including water, ethanol, 1-propanol, isopropanol, methanol, 1butanol, isobutanol, acetonitrile, acetone, ethyl acetate and methyl acetate, has been measured at temperatures between 278.15 and 318.15 K by a gravimetric method under atmospheric pressure.
Abstract: The solubility of benzophenone in various pure solvents, including water, ethanol, 1-propanol, isopropanol, methanol, 1-butanol, isobutanol, 1-octanol, acetonitrile, acetone, ethyl acetate, and methyl acetate, has been measured at temperatures between 278.15 and 318.15 K by a gravimetric method under atmospheric pressure. The solubility obtained in the selected pure solvents increases with the increasing temperature. Several thermodynamic models, including the modified Apelblat model, NRTL model, and Wilson model, were applied to correlate the measured solubility. It was found that the correlated results of the three models were in good agreement with the experimental results. In addition, the dissolution thermodynamic properties of benzophenone in the pure solvents were determined.
TL;DR: In this article, the reaction of hydrazine and benzophenone hydrazone with 2-acetonitrilium closo-decaborate (X)[B10H9NCMe] (X =“PhCH2PPh3, Ph4P, nBu4N) proceeds in MeCN or THF at RT for 30min giving 2-iminium closocdecaborates (X[B 10H9N(H) C(Me)NNR2] (R2
TL;DR: In this article, a high-throughput screening of 48 Lewis acids quickly identified Y(OTf)3 as an effective mediator of the addition reaction under mild conditions and used it to prepare key intermediates for the synthesis of PRMT5 inhibitors with high enantiopurity as well as numerous other amide and sulfonamide derivatives.
TL;DR: In this article, the reactivity of thorium-phosphorus bonds with benzophenone was investigated and a new thorium polyphosphide complex was reported from the reaction of (C5Me5)2ThCl2 with Na2(P4Ph4)(DME)3.
TL;DR: Different iron-oxygen oxidants are proposed to generate in situ in the reaction pathway depending upon the absence or presence of an external additive (such as protic acid or Lewis acid).
Abstract: A mononuclear iron(II)-α-hydroxy acid complex [(TpPh,Me)FeII(benzilate)] (TpPh,Me = hydrotris(3-phenyl-5-methylpyrazol-1-yl)borate) of a facial tridentate ligand has been isolated and characterized to explore its catalytic efficiency for aerial oxidation of organic substrates. In the reaction between the iron(II)-benzilate complex and O2, the metal-coordinated benzilate is stoichiometrically converted to benzophenone with concomitant reduction of dioxygen on the iron center. Based on the results from interception experiments and labeling studies, different iron-oxygen oxidants are proposed to generate in situ in the reaction pathway depending upon the absence or presence of an external additive (such as protic acid or Lewis acid). The five-coordinate iron(II) complex catalytically cis-dihydroxylates olefins and oxygenates the C–H bonds of aliphatic substrates using O2 as the terminal oxidant. The iron(II) complex exhibits better catalytic activity in the presence of a Lewis acid.
TL;DR: Investigation of the natural transition orbitals for the more important excitation bands of the absorption spectra indicates that crystallization of the benzophenone-containing molecules should present a stark contrast in photophysical properties versus that in solution, which was indeed reflected by their quantum efficiencies upon solid-state assembly.
Abstract: Supramolecular assembly of urea-tethered benzophenone molecules results in the formation of remarkably persistent triplet radical pairs upon UV irradiation at room temperature, whereas no radicals were observed in solution The factors that lead to emergent organic radicals are correlated with the microenvironment around the benzophenone carbonyl, types of proximal hydrogens, and the rigid supramolecular network The absorption spectra of the linear analogues were rationalized using time-dependent density functional theory calculations on the crystal structure and in dimethyl sulfoxide, employing an implicit solvation model to describe structural and electronic solvent effects Inspection of the natural transition orbitals for the more important excitation bands of the absorption spectra indicates that crystallization of the benzophenone-containing molecules should present a stark contrast in photophysical properties versus that in solution, which was indeed reflected by their quantum efficiencies upon so
TL;DR: In this article, two chemically modified β-cyclodextrin derivatives of 4,4´-diaminodiphenyl ether-bridged-bis-β-cyclodesxtrins were synthesized, and then they were respectively formed into inclusion complexes with benzophenone (BP) by co-precipitation method.
Abstract: In the paper, the two chemically modified β-cyclodextrin derivatives of 4,4´-diaminodiphenyl ether-bridged-bis-β-cyclodextrins (ODA-bis-β-CD) and p-aminobenzenesulfonic acid-β-cyclodextrin (ABS-β-CD) were synthesized, and then these two β-cyclodextrin derivatives were respectively formed into inclusion complexes with benzophenone (BP) by co-precipitation method. The structure of the inclusion complexes were characterized by UV/vis spectroscopy, FT-IR spectroscopy, elemental analysis, 1H NMR spectroscopy and XRD. Spectral titration was performed to study the inclusion behavior of the inclusion complexes. These experiments indicated that two inclusion complexes were formed at a stoichiometric ratio of 1:1 and the inclusion stability constants at different temperatures were calculated using the Benesi–Hildebrand (B–H) equation. The thermodynamic parameters (ΔG°, ΔH°, ΔS°) were obtained. As a result, it was found that the two chemically modified β-cyclodextrins containing BP were exothermic and spontaneous process (ΔG° < 0), and the processes of inclusion complexation were mainly enthalpy driven with negative or minor negative entropic contribution.
TL;DR: In this paper, a simple, selective, sensitive, rapid and robust spectrophotometric indirect-μ-solid phase extraction method was proposed for carbaryl with 4,4′-bis(4-aminophenoxy) benzophenone.
TL;DR: The reduced 2,2′-bipyridine thorium-bisborate mesityl complex (2) reacts with either propylene oxide or cyclohexene oxide to form ring-opened addition products 3 and 4, respectively.
TL;DR: The data suggest that the coordination of the ketone to MI can mostly be described by the resonance extremes of the Dewar-Chatt-Duncanson model, that is, the π complex and the metallaoxacycle extreme, with a possible minor contribution from a ketyl radical resonance structure in the case of the iron complex.
Abstract: π-Coordinating ligands are commonly found in intermediate structures in homogeneous catalysis, and are gaining interest as supporting ligands for the development of cooperative catalysts. Herein, we systematically investigate the binding of the ketone group - a strongly accepting π-ligand - to mid-to-late metals of the first transition series. To this end, the coordination of 2,2'-bis(diphenylphosphino)benzophenone (Phdpbp), featuring a ketone moiety flanked by two strongly binding P-donor groups, to Fe, Co, Ni and Cu is explored. The ketone moiety does not bind to the metal in M(II) complexes, whereas M(I) complexes (Fe, Co, Ni) adopt an η2(C,O)-coordination. A structural and computational investigation of periodic trends in this series was performed. These data suggest that the coordination of the ketone to M(I) can mostly be described by the resonance extremes of the Dewar-Chatt-Duncanson model, i.e. the π-complex and the metallaoxacycle extreme, with a possible minor contribution of a ketyl radical resonance structure in the case of the iron complex.
24 Sep 2018
TL;DR: The mechanistic aspects of hydroxyl and sulfate radical (SO4 −) induced oxidation of diphenylmethanol (DPM) in aqueous medium has been explored using a combined experimental and theoretical approach as discussed by the authors.
Abstract: The mechanistic aspects of hydroxyl ( OH) and sulfate radical (SO4 −) induced oxidation of diphenylmethanol (DPM) in aqueous medium has been explored using a combined experimental and theoretical approach. OH initiates the generation of hydroxycyclohexadienyl-type radicals (i) upon reaction with DPM (λmax = 330 nm; k2 = (1.44 ± 0.08) × 1010dm3 mol−1 s−1). Time-dependent density functional theory (TDDFT) calculations revealed an ortho-hydroxylated adduct structure to radical i, which shows comparable absorbance characteristics (λmax = 322 nm). High resolution mass spectrometric (HRMS) studies reveal the existence of mono- and di-hydroxylated compounds of DPM and benzophenone as the main degradation products. Hydroxylated products werederived from the radical i by either a radical-radical disproportion or a bimolecular transformation felicitated by molecular oxygen. Benzophenone (III) is likely originated from the radical cation (iii), generated as a result of one electron oxidation of DPM by OH/SO4 −, by deprotonation followed by electron and proton release.
TL;DR: In this article, Chen et al. proposed an approach to improve the performance of the state key laboratory of Tianjin University and the Tianjin Key Laboratory of Applied Catalysis Science and Technology.
TL;DR: A carbene-stabilized cyclic amino(carboranyl) silylene has been prepared from the reaction of cyclicamine chlorosilane with N-heterocyclic carbene via HCl elimination.
TL;DR: In this paper, a molecular design approach for blue-emitting thermally activated delayed fluorescence (TADF) molecules was presented, and two TADF emitters, (4-(3,6-di(pyridin-3-yl)-9H-carbazol-9-yl)phenyl)(phenyl)methanone (3PyCzBP) and (4.6-diphenyl-9h- carbazol 9-yl), were constructed with a pyridine-functionalized carbaz
Abstract: We report a molecular design approach for blue-emitting thermally activated delayed fluorescence (TADF) molecules. The two TADF emitters, (4-(3,6-di(pyridin-3-yl)-9H-carbazol-9-yl)phenyl)(phenyl)methanone (3PyCzBP) and (4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl)(phenyl)methanone (4PyCzBP), possess a pyridine-functionalized carbazole donor and a benzophenone acceptor. Both compounds show broad charge-transfer emission in dichloromethane with a λmax at 497 nm and a photoluminescence quantum yield, ϕPL, of 56% for 3PyCzBP and a λmax at 477 nm and a ϕPL of 52% for 4PyCzBP. The ϕPL decreased to 18% and 10%, respectively, for 3PyCzBP and 4PyCzBP in the presence of O2 confirming that triplet states involved in emission. The poly(methyl methacrylate) (PMMA)-doped (10 wt. %) films show blueshifted emission with λmax at 450 and 449 nm for 3PyCzBP and 4PyCzBP, respectively. The maximum ϕPL of 23.4% is achieved for these compounds in PMMA-doped film. The difference in energy between the singlet and triplet excited states (ΔEST) is very small at 0.06 and 0.07 eV for 3PyCzBP and 4PyCzBP, respectively. Multilayer organic light-emitting diode devices fabricated using these molecules as emitters show that the maximum efficiency (EQEmax) of the blue devices is 5.0%.