Presence Of Β-diketones Research Articles

Supramolecular structure of azodye rhodanine compounds and their complexes: a review

The optical absorption properties of 5-(4′-derivatives phenylazo)-2-thioxothiazolidin-4-one (HLn) (where X = H) thin films have been studied. It was found that the values of the energy band gap, Eg, for derivatives were in the range of 1.77–2.29 eV depending on the nature of the substituent. The optical values of the energy band gap (Eg) for all derivatives near the absorption edge were found to be direct allowed transition. The synthesized ligands (HLn) (where X = H) were screened as antibacterial and antifungal agents. The proton–ligand dissociation constant of the rhodanine azo derivatives (HLn) (where X = H and X = P-OCH3Ph) and metal–ligand stability constants of their complexes with metal ions (Mn2+, Co2+, Ni2+, Cu2+ and Zn2+) have been determined potentiometrically in 0.1 M KCl. The stoichiometries of copper(II) and cadmium(II) complexes of HLn (where X = Ph) were determined conductometrically and indicated the formation of 1:1 and 1:2 (metal:ligand) complexes. The molar ratio of ligand (HLn) (where X = H) and Ru(III) complexes is (1:2)/(1:3)(M:Ln), respectively. The study revealed octahedral geometry around Ru(III) complexes. A series of heterocyclic mixed ligands of oxovanadium(IV) complexes have been synthesized by the reaction of vanadium(IV) sulfate with rhodanine azo (HLn) (where X = H) in the presence of β-diketone (LH). Palladium(II) complexes of the general formula [Pd(Ln)L] (where LH = diketone = acetylacetone, HLn = azorhodanine) have been synthesized. In these complexes, the azo ligand acts as a monobasic bidentate ligand and is coordinated to the metal ion through the azo-nitrogen, enolic oxygen atoms forming stable six-membered heterocyclic rings. The D.C. electrical conductivity of HLn (where X = Ph) and their complexes were measured. The bond lengths and the force constants have been calculated for uranyl complexes (26–30) of HLn (where X = Ph). The plotting of r1, r2 and r3 (bond distance, rU–O) versus ν3 give a straight line with increasing the value of ν3 and decreasing rU–O.

Nickel-catalysed Suzuki–Miyaura cross-coupling reactions of aryl halides with arylboronic acids in ionic liquids

An efficient strategy for the nickel-catalysed synthesis of biaryls and terphenyls has been developed in environmentally-friendly reaction media. In the presence of β-diketone and PPh3 ligands, Ni(TFA)2 acted as an effective catalyst for the Suzuki–Miyaura cross-coupling of aryl halides and arylboronic acids in an ionic liquid solution. Biaryls and terphenyls were obtained in good yields under this catalytic system.

Reaction of [VO(OPr)3] with hexamethyldisylthiane in the presence of β-diketones

The reaction of [VO(OPr)3] (Pr is n-propyl) with hexamethyldisylthiane Me3SiSSiMe3 in the presence of β-diketones (acetylacetone (HAcac), hexafluoroacetylacetone (Hfac), and dipivaloylmethane (Dpm)), is studied. In all cases, vanadium(IV) and vanadium(III) β-diketonate complexes of different types are formed. New crystalline modification [V(Acac)3] is obtained in the reaction with HAcac. The mixedligand vanadium(III) complex of the composition [V2(Hfac)2(μ-OPr)]2 is formed with Hfac. In the presence of Dpm, the known vanadium(IV) complex [V2O2(Dpm)2(μ-OPr)2] is obtained in which two vanadyl groups VO2+ are linked by two bridging propoxy groups. The structures of all products are determined by X-ray diffraction analysis.

Electrochemical Study of Catechol Derivatives in the Presence of β-diketones: Synthesis of Benzofuran Derivatives

The electrochemical oxidation of 4-(1,3-dithiolan-2-yl)benzene-1,2-diol was studied in the presence and absence of acetylacetone (2a), dimedone (2b) and 4-hydroxycoumarin (2c) as nucleophiles in aqueous solution by means of cyclic voltammetry and controlled-potential coulometry. The results indicate that these nucleophiles participate in Michael addition reaction with the oxidized form of catechol derivatives, and then convert it to the corresponding new benzofuran derivatives. The electrochemical synthesis of compounds has been successfully performed at a carbon rod electrode and in two-compartment cell. The observed homogeneous rate constants (kobs) of the reaction of oxidized form of catechol derivatives with 2a-c as nucleophiles were estimated by comparing the experimental cyclic voltammograms with the digital simulated results. The calculated kobs was found to vary in the order 4-hydroxycoumarin (2c) < dimedone (2b) < acetylacetone (2a).

Electrochemical production of novel products from 2,3-dimethylhydroquinone in the presence of some β-diketones

Electrochemical oxidation of 2,3-dimethylhydroquinone has been studied in the presence of β-diketones as nucleophiles in aqueous solution using cyclic voltammetry and controlled-potential coulometry. The results indicate that the derivatives of 2,3-dimethylhydroquinone participate in a Michael addition reaction to form the corresponding benzofuran derivatives. The electrochemical synthesis has been successfully performed at pH 7.0 and E = 0.1 V versus an Ag|AgCl|KCl (3 M) in an undivided cell in good yield and purity.

Electrochemical Oxidation of 4-Methylcatechol in the Presence of β-Diketones

Abstract Electrochemical oxidation of 4-methylcatechol (1) in the presence of, benzoylacetone (2), dibenzoylmethane (3), 3-hydroxy-1H-phenalen-1-one (4), acetylacetone (5), dimedone (6), and 2-acetylcyclohexanone (7) as nucleophiles has been studied in detail by cyclic voltammetry and controlled-potential coulometry. The results indicate that the electrochemically generated quinone participates in Michael addition reaction with 2–7 via various mechanisms to produce new organic compounds. Furthermore, our studies show that the structure of intermediates play a crucial role in product selectivity under controlled-potential conditions. Various types of products were also obtained through the selective oxidation at the surface of a carbon electrode in an undivided cell.

Anodic Dissolution of U3Si and UMo in Nonaqueous Media

Anodic dissolution of Mo, U3Si, and UMo in dry acetonitrile containing 0.1 M (C2H5)4 NCl and in anhydrous and 96% ethanol containing 0.1 M LiCl was studied under potentiostatic conditions. The oxidation potentials of the U and Mo alloys were determined. Anodic dissolution of UMo in the presence of β-diketones yields uranium and molybdenum chelates, and anodic dissolution of U3Si yields U(IV) chelates in an inert medium. The conditions for electrochemical preparation of uranyl β-diketonates involving oxidation of U(IV) with atmospheric oxygen in the course of electrolysis were determined.

One-step synthesis of the chelate oxides of bis(trialkylantimony) by an oxidative method

The chelate oxides of bis(trimethylantimony) (Me3SbL1)2O (i = 1 or 2, L1-acetylacetonate, L2 - trifluoroacetylacetonate) and bis(triethylantimony) (Et3SbL1)2O have been obtained in 79–85% yields by a one-step oxidation of trialkylantimony withtertbutylhydroperoxide in the presence of β-diketones in benzene at 20 °C.

Synthesis of triphenylantimony (hydroxo)diketonates by oxidative methods

Triphenylantimony (hydroxo)acetylacetonate, (hydroxo)trifluoroacetylacetonate, and (hydroxo)pivaloyltrifluoroacetonate were prepared in 85–98 % yields by oxidation of triphenylantimony with hydrogen peroxide ortert-butyl hydroperoxide in the presence of β-diketones.

Chemical genetics of β-diketone formation in wheat

Glaucous lines of wheat are characterized by the presence of β-diketones in the wax on non-vegetative organs. Green (non-glaucous) lines possess, at most, only a trace of β-diketone. Comparison of a glaucous line with a green line, deficient for a chromosome arm carrying a wax-producing gene, shows that suppression of β-diketone formation is correlated with the appearance of normal primary alcohols, which are absent from the glaucous plants. It is suggested that the primary alcohols are formed from a precursor of the β-diketones.