Dibenzoyl methane

Methane, dibenzoyl-metal complexes stability, 366 Methane, dipivaloyl-metal complexes decomposition, 385 Methanediamine metal complexes, 30 Methanide, dicyanonitroso-metal complexes, 263 Methanide, tricyano-metal complexes, 263... 

Dibenzoylmcthane has been prepared by the hydrolysis of dibenzoyl acetic acid 1 by the slow spontaneous decomposition of acetyl dibenzoyl methane 2 by the action of metallic sodium,3 sodium ethylate,3 sodium methylate,4 alchoholic potash,4 or sodamide 5 on mixtures of acetophenone and ethyl benzoate and by the action of alcoholic potash,6 sodium methylate,7 or sodium ethylate 8 on benzalacetophenone dibromide. 

Nitrene addition to alkenes can be aided by the nse of a transition metal, such as copper, rhodium, ruthenium, iron, cobalt, etc. NHC-Cu catalysts have been used in nitrene addition. For example [Cu(DBM)(IPr)] 147 (DBM = dibenzoyl-methane) was successfully employed in the aziridination of aliphatic alkenes 144 in presence of trichloroethylsulfamate ester 145 and iodosobenzene 146 (Scheme 5.38) [43]. 

A 50-ml Schlenk tube containing a stirrer bar was charged with 3.4 ml of toluene, vinyl acetate (71 mmol), tris(2,2,2-trifluorethyl) phosphite (0.36 mmol), and dibenzoyl peroxide (0.18 mmol) successively at 60°C. The reaction mixture was then stirred in the closed Schlenk tube at 70°C for 2 hours and then treated with bis(ally-loxy)methane (3.56 mmol) and stirred at 70°C for 20 hours. All volatile components were then removed using an oil pump vacuum. The polymer was dissolved in acetone and then precipitated in heptane and 1.78 g product isolated as a white powder. 

However, the reaction of tri-a-butylarsine oxide with dibenzoyl-methane or with dimethyl malonate in triethylamine and in the presence of phosphorus pentoxide gave the corresponding ylides (11), respectively, (20, 40). 

Condensation between selenium tetrachloride and copper dibenzoyl-methane like the preceding condensations gives rise to two products. In the simpler case one molecule of tetrachloride reacts ... 

The polymer was imprinted with dibenzoyl-methane (42), a 1,3-diketone able to be held in place by formation of a complex with the Co(II) ion, and structurally similar to the product of the cross-aldol condensation. A schematic representation of this approach is given in Scheme 7. 

Chelating extractants such as beta-diketones, tropolones, hydroxyoximes, and 8-hydroxyquinolines (Figure 2.1), have been used extensively for the extraction of actinide ions from moderate to weakly acidic solutions (15-17). Beta-diketones such as acetylacetone (acac), HTTA, benzoyl trifluoroacetone (BTFA), and dibenzoyl-methane (HDBM) have been commonly used for the separation of actinide ions. The extraction mechanism involved formation of the enol form of the beta-diketone prior to complexation and extraction of the metal ion (Figure 2.2). 

MOPO 4-methoxy, pyridine-N-oxide HDBM dibenzoyl methane... 

This reaction has been made with various carbonyl compounds, e.g., cyclopentanone,27 cyclohexanone,20 cycloheptanone,27 cycloocta-none,27 1-tetralone,21 2-tetralone,28 variously substituted acetophenones,29 phenyl benzyl ketone,29 dibenzyl ketone,29 dibenzoyl-methane,18, 30 ethyl benzoylacetate,18 ethyl malonate,30 malon-anilide,30 and 2-(bisalkylthio)methylenecyclopentanones and cyclohexanones.27... 

Up to about the 1960 s, elemental analysis coupled with absorption spectra and infrared spectra and X-ray crystallography were the primary methods used in the studies of complexes. Later on with the developments in nuclear magnetic resonance (NMR) spectroscopy, especially multinuclear NMR, this technique has been invariably used in the studies of structural features of lanthanide complexes. To illustrate these points some references to literature are herein pointed out. The studies on the rare earth 1,3-diketonates, where 1,3-diketones are acetyl acetone, benzoyl acetone, dibenzoyl methane and 2-thienoyl tri-fluoroacetone totally relied on elemental analysis, UV-Vis and IR spectra to establish the nature of the complexes [89]. The important role played by X-ray crystallography in the elucidation of the structures of lanthanide complexes has been extensively discussed in Chapter 5 and the use of this technique goes as far back as the 1960 s. Nevertheless it continues to play a major role in the studies of lanthanide complexes. 

The influence of a beta-diketone on the already observed anomalous behaviour of preheated metal stearates, e.g. zinc stearate, calcium soap, as heat stabilisers for PVC was evaluated using dibenzoyl methane (Rhodastab-83), a short-term costabiliser. 19 refs. 

Aluminum hydroxide carboxylic acid salts of dibenzoyl methane derivatives, (IV), are also effective as UV-A absorbers (4). 

Natural waters Co-precipitation with Fe(OH)3 selective separation by precipitation determined as dibenzoyl methane complex Laser fluorometry 5 ppb No data Eral 1989 > > r < H O... 

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