Aromatic Diketones Research Articles

Synthesis of Disecondary Aromatic Diols

The synthesis of disecondary aromatic diols (the main precursors for divinyl aromatic monomers) was carried out. The optimal conditions for the preparation of these diols by selective catalytic hydrogenation of aromatic diketones in the presence of Raney nickel and by reduction of these diketones by sodium borohydride were established. It was demonstrated that sodium borohydride reduction afforded the pure diols under mild and relatively safe conditions (in the systems of CHCl3–PEG400–H2O, at room temperature and atmospheric pressure).

Dark and sunlight-driven dye degradation over a TiO2–dibenzoylmethane hybrid xerogel

The pursuit of sustainable and inexpensive systems for the degradation of organic aquatic pollutants working under sunlight or even without irradiation is still open. Herein, an amorphous titanium oxide modified with dibenzoylmethane, an aromatic diketone, is proposed as a solar photocatalyst showing oxidative activity also in the dark. Ti(IV)-dibenzoylmethanate (dbm) complexes form during the sol-gel synthesis and are dispersed throughout the oxide gel structure. This ligand-to-metal charge transfer complex plays a dual role: it enables visible light absorption, narrowing the apparent band gap, and provides localized surface charge, promoting the spontaneous formation and stabilization of superoxide radical ions by reduction of O2. The activity of the TiO2-dbm hybrid was assessed in the removal of methylene blue from aqueous solution. The results demonstrated a rather stable photocatalytic activity under natural sunlight, exceeding 80% dye removal after 1 h in four subsequent tests, a value that was mostly recovered after a mild regeneration. Considerable efficiencies were also achieved in the dark, owing to the immobilized superoxide radicals acting as initiators of degradation pathways. Finally, the influence of the operating conditions (pH, illumination, mixing method, water contact) on the efficiency and durability of the performances was evaluated to survey the long-term utilization in water decontamination. The behaviour of this hybrid material resembles a “photocatalytic memory” effect and may widen the perspectives for the development of heterogeneous advanced oxidation processes.

Keto-enol equilibrium: stable tautomers of ortho-, meta-, and para-hydroquinones in large aromatics.

The synthesis of [6]helicene para-quinone starting from the 1,4-dimethoxy-[6]helicene derivative is presented. The demethylation reaction with boron tribromide led to unexpected results. Instead of the expected para-hydroquinone, the diketone tautomeric form was isolated. In contrast to the 1,4-hydroquinone and 1,4-dihydroxynaphthalene, the stable tautomers for the [4] and [6]helicenes were the aromatic diketones. These experimental results were corroborated by calculations. Additional calculations showed that these tautomeric species were indeed the stable forms of 1,4 and 1,3-hydroquinones when present in larger aromatics, in drastic contrast with 1,2-dihydroxy-aromatics (known as catechol).

Ladder‐Like Difluoroindacenodithiophene‐4,9‐dione Derivative: A New Acceptor System for High‐Mobility n‐Type Polymer Semiconductors

AbstractLadder‐like aromatic diketones (LADK), which possess a coplanar π‐extended geometry, a high electron deficiency as well as various attractive optoelectronic properties, are demonstrated as the promising candidates in building small‐molecule organic electron‐transporting materials, yet reports on direct integration of these structural motifs into n‐type polymers are rarely accessed. Herein, it is demonstrated that a possibility of realizing unipolar n‐type characteristics of such acceptor system by developing two novel donor–acceptor type polymers, in which the newly developed LADK unit, named as 3,8‐bis(2‐decyltetradecyl)‐5,10‐difluoro‐s‐indaceno[1,2‐b:5,6‐b′]dithiophene‐4,9‐dione (FIDTO‐R), is adopted as the acceptor segments. The resulting polymers present deep‐lying unoccupied molecular orbital levels (as low as −3.84 eV), compact π–π stacking (d‐spacing, ≈3.57 Å) coupled with uniform nanofiber‐like surface morphology. All these factors contribute to excellent unipolar n‐type characteristics with high electron mobilities of 0.27 and 1.01 cm2 V−1 s−1, together with high inverter gain values of 141 and 80, respectively. The recorded values are among the best in n‐type polymer field‐effect transistors and associated inverter circuits. These findings unambiguously reveal that the as‐prepared FIDTO‐R and its analog LADK derivatives are another type of excellent building blocks for the construction of high‐mobility n‐type polymers.

Solvation, rotational dynamics, photophysical properties study of aromatic asymmetric di-ketones: An experimental and theoretical approach

In this article we have investigated the solvation, rotational dynamics and photo physics of diketone derivatives DK-2 and DK-3 in alcohols and alkanes at room temperature through both a time-resolved fluorescence depolarization technique and steady state. Viscosity of dissolvable varies linearly with respect to rotational times of the molecule. Outcomes are investigated by utilizing the theory of hydrodynamic (SED) Stokes- Einstein-Debye to evaluate the friction with stick and slip limiting conditions. In addition, using the solvatochromic shift and quantum chemical technique aromatic di-ketone derivatives, 1-(4′-dodecyl-[1,1′-biphenyl]-4-yl)-3-(4-ethoxyphenyl) propane-1,3-dione (DK-2) and 1-(4′-dodecyl-[1,1′-biphenyl]-4-yl)-3-(4-(nonyloxy)phenyl)propane-1,3-dione (DK-3) estimated properties of fluorescence. The excitation and emission spectra of DK-2 and DK-3 have been observed in several solvents. The dipole moments calculated using DFT theory and solvatochromic correlations. Estimated (μg) value by DFT theory is relatively greater than the solvatochromic shift techniques. The dipole moments of excited state (μe) are found to be more prominent than dipole moment of ground states (μg) which approves π → π* transition. The variance of dipole moments (Δμ) was determined from microscopic solvent polarity parameter (ETN) and solvatochromic shift technique and outcomes are compared.

Properties of the Cured Polymer from an Epoxy Resin Having an Aromatic Diketone Structure and Phenol Novolac

Properties of the Cured Polymer from an Epoxy Resin Having an Aromatic Diketone Structure and Phenol Novolac

Synthesis of Chiral Poly(silyl ether)s via CuH-Catalyzed Asymmetric Hydrosilylation Polymerization of Diketones with Silanes

The precise synthesis of chiral poly(silyl ether)s remains a challenge, in contrast to the well-studied preparation of poly(silyl ether)s. Herein, an unprecedented approach for the synthesis of optically active poly(silyl ether)s with main-chain chirality has been developed via CuH-catalyzed hydrosilylation polymerization of diketones and silanes. The polymerization features low catalyst loading, mild condition, and broad substrate scope, including a wide range of aromatic diketones and heteroaromatic diketones with excellent yields and enantioselectivities (up to 98% yield and 99% ee). Thermal analysis indicated chiral poly(silyl ether)s exhibit good thermal properties. These enantiomerically enriched poly(silyl ether)s with good thermal stability have a promising application in chiral separation.

Head‐to‐Tail Dimerization of 4‐Fluoroacetophenone in the KOH/DMSO Superbase Suspension and Related SNAr Reaction

The head‐to‐tail autocondensation of 4‐fluoroacetophenone in the KOH/DMSO superbase suspension stops on dimerization step affording 4‐acetylbenzyl‐4'‐fluorophenylketone in 96 % yield. Further condensation of the diketone formed is prevented by a weaker electron‐withdrawing effect of enolate spacer, –CH=C(OK)–. 2‐Fluoro‐ and 3‐fluoroacetophenones are inactive in this reaction. Other superbases of the type MOR/DMSO (M = Na, K; R = H, OBut) are inferior in promotion of this reaction providing 71–76 % yields of the dimeric ketone. Other weak acids like non‐fluorinated acylbenzenes prove to be also capable of forming Csp2–Csp3 bond with 4‐fluoroacetophenone under similar conditions. This new group of fluorine substitution (SNAr) reaction opens a short and simple route to so far inaccessible aromatic diketones via the nucleophilic substitution of fluorine atom in 4‐fluoroacetophenone by available acylbenzenes. The quantum‐chemical rationale of the observed substitution process as competing with aldol condensation is suggested.

Carbonyl reductase sniffer from the model organism daphnia: Cloning, substrate determination and inhibitory sensitivity

Carbonyl reductases (CRs) represent a fundamental enzymatic defense mechanism against oxidative stress. While commonly two carbonyl reductases (CBR1 and CBR3) are found in mammalian genomes, invertebrate model organisms like Drosophila melanogaster express no CR but a functional homolog to human CBR1, termed sniffer. The importance of sniffer could be demonstrated in D. melanogaster where it protected against age-dependent neurodegeneration. Interestingly, the microcrustacean Daphnia harbors four copies of the CR gene (CR1, CR2, CR3, CR4) in addition to one sniffer gene. Due to this unique equipment Daphnia is an ideal model organism to investigate the function of sniffer. Recombinant sniffer from D. magna und D. pules were produced in E. coli, purified by Ni-affinity chromatography and tested with a variety of aliphatic and aromatic diketones, reactive aldehydes and precursors of advanced glycation end products (AGE). The highest catalytic activities were determined for sniffer from D. pulex with the aromatic dicarbonyls 9,10-phenanthrenequinone (kcat/Km = 2.6 s−1 x μM−1) and isatin (kcat/Km = 1.5 s−1 x μM−1). While sniffer from D. magna displayed preference for the same two substances, the respective catalytic activities were noticeably lower. Kinetic constants with aliphatic diketones were generally lower than those with aromatic dicarbonyls for both sniffer enzymes. The best aliphatic diketone as substrate for sniffer from D. magna and D. pulex was hexane-3,4-dione with kcat/Km = 0.23 s−1 μM−1 and kcat/Km = 0.35 s−1 μM−1, respectively. Poor or no detectable activity of the two sniffer enzymes was seen with the aliphatic diketones 2,5-hexanedione and 3,5-heptanedione, the aldehydes butanal, hexanal, decanal, crotonaldehyde, acrolein, trans-2-hexenal, and the AGE precursors glyoxal, methylglyoxal, furfural and glyceraldehyde, indicating no physiological function in the metabolism of short-chain aldehydes. Substrate inhibition for both sniffer enzymes was observed with the quinone substrates 1,4-naphthoquinone and 2-methyl-1,4-benzoquinone. From a variety of pesticides endosulfan turned out as an effective inhibitor of the sniffer enzymes (Ki = 9.2 μM for sniffer from D. magna, Ki = 12.0 μM for sniffer from D. pulex). In conclusion, the present results on sniffer from the protein superfamily of the short-chain dehydrogenases/reductases (SDR) in Daphnia ssp. complement earlier studies on carbonyl reductases in the same species and indicate that Daphnia is an interesting model to study the overall response to carbonyl stress.

A Case of Self‐Organization in Highly Emissive EuIII Ionic Liquids

Intrinsic photoluminescent ionic liquids based on europium(III) tetrakis(β‐diketonate) complexes with a tetraalkylphosphonium as the counterion were synthesized. Two are room temperature ionic liquids; [P6,6,6,14][Eu(fod)4] (1) {fod is 1,1,1,2,2,3,3‐heptafluoro‐7,7‐dimethyloctane‐4,6‐dionate} and [P6,6,6,14][Eu(fod)3(dbm)] (2) {dbm is dibenzoylmethanate}, while calorimetric measurements showed a melting point at 415 K for [P6,6,6,14][Eu(dbm)4] (3). The luminescence quantum yields determined for 1, 2, and 3 are 34, 59 %, and 64 %, respectively. The photoluminescence and thermochemical properties of the complexes were investigated in detail and the influence of the long chain tetraalkylphosphonium counterion, together with the aromatic diketone ligand, on the unusual thermal behavior of 2 is discussed.

Crystal structure of 1-benzoyl-2,7-dimethoxy-8-(3,5-dimethylbenzoyl) naphthalene: Head-to-head fashioned molecular motif for accumulating weak non-classical hydrogen bonds

Title compound, 1-benzoyl-2,7-dimethoxy-8-(3,5-dimethylbenzoyl)naphthalene, an unsymmetrically substituted aromatic diketone compound having non-coplanarly accumulated aromatic rings structure, has been synthesized and its crystal structure has been determined by X-ray crystallography. The asymmetric unit of title compound contains two independent conformers. For each conformer, the two aroyl groups are non-coplanarly situated against the naphthalene ring plane and oriented in an opposite direction. The 3,5-dimethylbenzoyl group leans more than the non-substituted benzoyl group on the other peri -position of the naphthalene ring. The characteristics in the single molecular crystal structure of this unsymmetrical compound show unique relationship with two symmetrically substituted homologues, namely 1,8-dibenzoyl-2,7-dimethoxynaphthalene and 2,7-dimethoxy-1,8-bis(3,5-dimethylbenzoyl) naphthalene. Dihedral angles between 3,5-dimethylbenzene ring and naphthalene ring of 2,7-dimethoxy-1,8-bis(3,5-dimethylbenzoyl)naphthalene are larger than those between benzene ring and naphthalene ring of 1,8-dibenzoyl-2,7-dimethoxynaphthalene. Dihedral angle between 3,5-dimethylbenzoyl group and naphthalene ring in title compound is close to those of symmetrical homologue having two 3,5-dimethylbenzoyl groups. In the similar manner, dihedral angle between non-substituted benzoyl group and naphthalene ring in title compound is also close to those of symmetrical homologue bearing two non-substituted benzoyl groups. On the other hand, the crystal packing of title compound has rather similar feature with 2,7-dimethoxy-1,8-bis(3,5-dimethylbenzoyl)naphthalene. Two compounds have common crystalline molecular structural motif of head-to-head fashioned intermolecular interaction of 3,5-dimethylbenzoyl moieties. It is interpreted that the interactions between (sp 3 )C–H and π orbital preferentially govern the molecular packing motif. Molecular structure feature of title compound and the symmetrically 3,5-dimethylbenzoylated homologue strongly manifests that accumulation of weak non-classical hydrogen bonds play a crucial role in determination of the crystal packing rather than sole function of stronger non-classical hydrogen bond and π…π stacking.

Dimethylzinc-Mediated Addition of Phenylacetylene to α-Diketones Catalyzed by Chiral Perhydro-1,3-benzoxazines.

An efficient, enantioselective Me2Zn-mediated monoaddition of phenylacetylene to α-diketones in the presence of a chiral perhydro-1,3-benzoxazine ligand is described. At temperatures higher than -20 °C, a kinetic resolution of the resulting α-hydroxy ketone occurs, which greatly improves the enantioselectivity although with moderate chemical yield. The alkynylation of nonsymmetrical aromatic diketones with electronically different substituents on the aromatic rings proceed with high regioselectivity. This procedure allows the preparation of α-hydroxy-α-ynyl ketones as highly enantioenriched materials.

Hydrophobic Porous Polyketimines for the Capture of CO2.

A new type of porous polymers is presented. Polyketimines (PPKs) were synthesized by condensing 1,3,5-tris(4-aminophenyl)benzene with aromatic diketones using p-toluenesulfonic acid catalyst. They were characterized by infrared spectroscopy and solid-state 13 C{1 H} nuclear magnetic resonance spectroscopy, and their porosities were probed through the adsorption of N2 and CO2 . The PPKs had low uptakes of N2 (at -196 °C), which was attributed to diffusion limitations and/or a shrinking of the polymer. They had relatively high uptakes of CO2 (at 0 °C; up to 1.26 mmol g-1 at 0.15 bar and 2.99 mmol g-1 at 1 bar), which was related to ultramicropores (6-9 Å). The PPKs had high estimated CO2 -over-N2 selectivities (30-40 at 0 °C). Studies on the vapor adsorption of water and ethanol showed the PPKs to be moderately hydrophobic and had a high uptake of ethanol at low partial pressures.

Design, synthesis and biological activity of aromatic diketone derivatives as HIV-1 integrase inhibitors.

A series of aromatic diketone derivatives were designed and synthesized as potential HIV-1 integrase (IN) inhibitors and evaluated to determine their ability to inhibit the strand transfer process of HIV-1 integrase. The results indicate that (Z)-1-(3-acetyl-2-hydroxy-4,6-dimethoxyphenyl)-3-hydroxy-3-(substituted)phenylprop-2-en-1-one (5a-5d) can moderately inhibit HIV-1 integrase. The cyclization and condensation products (6a-6c and 7e-7f) of compounds 5a-5d show poor inhibitory activity against HIV-1 integrase. The molecular docking results indicate that the different types of compounds act on HIV-1 integrase in different ways, and these results can explain the differences in the inhibitory activities.

Electrochemical Investigations of Benzil in Nonaqueous Media

Introduction The electrochemical behavior of the aromatic diketone benzil has been studied in a number of solvents (1-4). The benzil system is particularly interesting because of its ability to undergo various reactions accompanying the reduction process. Most of the solvent systems studied to date have involved proton-donating properties to some degree, so the use of the ionic liquid 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate ( BMPY TfO ) provides a useful contrast to the other solvents. Experimental All electrochemical experiments were carried out in a Vacuum Atmospheres glovebox. Cyclic voltammograms were obtained on a PAR 283 potentiostat using PowerSuite software. Potentials are reported with respect to an Ag/AgCl reference electrode. 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate (BMPY TfO) was prepared by a literature method (5). Benzil was obtained from Aldrich Chemical Company.Results and Discussion As can be observed from Figure 1(a), benzil undergoes electrochemical reduction in BMPY TfO in two successive, reversible electron-transfer steps. Figure 1(b) shows the voltammetric behavior for only the first process. In contrast, reduction in other nonaqueous solvents such as acetonitrile and dimethylformamide (2,3) involves considerable irreversibility for the second process. The low proton-donating ability of BMPY TfO seems largely to account for this effect. The ionic liquid BMPY TfO, then, serves as a suitable solvent for observing relatively uncomplicated voltammetric behavior of benzil, presenting the possibility of studying the effect of added proton donors in this solvent.ReferencesH. E. Stapelfeldt and S. P. Perone, Analytical Chemistry, 41(4), 623 (1969).M. D. Ryan and D. H. Evans, J. Electroanal. Chem., 67, 333 (1976).M. Chandrasekaran, M. Noel and V. Krishnan,J. Chem. Soc., Perkin Trans.2, 979 (1992).G. T. Cheek, ECS Transactions, 6(6), 47 (2007).L. Crowhurst, N. L. Lancaster, J. M. P. Arlandis, and T. Welton, J. Am. Chem. Soc., 126, 11549 (2004). Figure 1. Cyclic voltammetry of 40 mM benzil in BMPY TfO at glassy carbon ( 1 mm diameter ). Scan rate 100 mV/s(a) Scan to -2.50 V [ black curve ] (b) Scan reversal at -1.50 V [ red curve ]

Microwave-Assisted Synthesis of Functionalized Shvo-Type Complexes

A simple and expeditious microwave-assisted procedure for the synthesis of a variety of Shvo-type ruthenium complexes has been developed by reacting Ru3(CO)12 with variously functionalized tetraarylcyclopentadienones under microwave irradiation in MeOH. Ligand precursors have also been prepared under microwave heating by a bis-aldol condensation of 1,3-diphenylacetone with variously functionalized aromatic diketones. All the reactions were very fast and clean, leading to good yields and purities.

ChemInform Abstract: NHC‐Catalyzed Annulation of Enals to Ene‐1,4‐diones: Stereoselective Synthesis of 1,3‐Diaryl‐4‐acyl Cyclopentenes.

AbstractThe optimized system is successfully applied to various aromatic diketones and aldehydes to produce highly functionalized trans‐cyclopentene structures.

Role of Boron in the Polymer Chemistry and Photophysical Properties of Difluoroboron−Dibenzoylmethane Polylactide

Difluoroboron β-diketonate−polymer conjugates have remarkable solid-state luminescent properties that are useful in a variety of fields including multiphoton microscopy, cell biology, and tumor hypoxia imaging. Despite the successful applications of these systems, the role of boron in these polymeric materials has not been thoroughly investigated. Here we explore a boron-free model system with dibenzoylmethane chromophores in poly(lactic acid) (PLA) for comparison. The hydroxyl-functionalized aromatic diketone, dibenzoylmethane (dbmOH), is weakly fluorescent in the solid state and nonfluorescent in solution while its difluoroboron complex (BF2dbmOH) is highly emissive in both states. Using dbmOH and BF2dbmOH as initiators, well-defined end-functionalized polylactides, dbmPLA and BF2dbmPLA, were obtained via tin-catalyzed controlled ring-opening polymerization. Boronation of the dbmOH initiator affects the polymerization kinetics and the photophysical properties of the resulting BF2dbmPLA material. Both db...

Formal intramolecular photoredox chemistry of anthraquinones in aqueous solution: photodeprotection for alcohols, aldehydes and ketones

The formal intramolecular photoredox reaction initially discovered for the parent 2-(hydroxymethyl)anthraquinone (1) in aqueous solution has been extended to a variety of anthraquinones derivatives 6-13, to explore the generality of the reaction, and to investigate its potential utility as a photodeprotecting chromophore. In addition, the related diketone 14 was studied to investigate the need for the anthraquinone chromophore in these formal intramolecular reactions. All the anthraquinones studied (except for 9) undergo formal unimolecular photoredox reaction with a range of quantum yields (Phi = 0.02-0.7). Anthraquinones 7, 8, 10 and 11 photoreleased the corresponding alcohol, aldehyde, or ketone with good yields (80-90%), making it potentially useful for photocaging in aqueous solution. Diketone 14 undergoes an analogous photoredox reaction but only in acid (Phi = 0.003, pH < 1), to give the formal redox product diphenylisobenzofuran 32 thereby demonstrating that other aromatic diketones can react in an analogous fashion. The ionic photochemistry exhibited by these aromatic ketones is fully compatible with the recent discovery of the surprising acid-catalyzed photochemical hydration of benzophenone reported by Jacob Wirz and coworkers (M. Ramseier, P. Senn and J. Wirz, J. Phys. Chem. A, 2003, 107, 3305-3315).

Effect of Various Organic Precursors on the Performance of LiFePO4 ∕ C Composite Cathode by Coprecipitation Method

The goal of this research was to study the effect of organic precursors with functionalized aromatic anhydrides or aromatic diketones on the performance of the composite. A coprecipitation method was applied to prepare a series of materials by calcinating amorphous with organic precursors at . The materials were characterized by X-ray diffraction, scanning electron microscopy, particle size analysis, thermal analysis, Brunauer-Emmett-Teller specific surface area and electrochemical methods. The obtained composites showed a well-ordered olivine-type structure with a minor impurity. The occurrence of the phase can be attributed to the relatively high temperature of . The composites produced by pyrolysis of an aromatic diketone with a longer alkoxy branch exhibited a better capacity compared to other types of organic compounds. The longer alkoxy aromatic diketone showed a better performance because its decomposition temperature was close to the temperature of the phase transformation resulting in a fine particle size and uniform carbon distribution on the composite surface. The performance of different organic precursors showed a strong relationship with its decomposition temperature, but was not in correlation with its weight loss. According to Raman spectral analysis, longer alkoxy aromatic diketones have a larger peak ratio indicating higher uniform and carbon content coating on particles.