Complexes difluoride

A mixture of an acid anhydride and a ketone is saturated with boron trifluoride this is followed by treatment with aqueous sodium acetate. The quantity of boron trifluoride absorbed usually amounts to 100 mol per cent, (based on total mola of ketone and anhydride). Catalytic amounts of the reagent do not give satisfactory results. This is in line with the observation that the p diketone is produced in the reaction mixture as the boron difluoride complex, some of which have been isolated. A reasonable mechanism of the reaction postulates the conversion of the anhydride into a carbonium ion, such as (I) the ketone into an enol type of complex, such as (II) followed by condensation of (I) and (II) to yield the boron difluoride complex of the p diketone (III) ... 

The horon difluoride coordination complex is decomposed by heating under reflux with an aqueous solution of 2 mols of sodium acetate per mol of anhydride, whereupon the p diketone (acetylacetone) is liberated. 

Both the binary and complex fluorides of aluminum have played a significant role in the aluminum industry. Aluminum trifluoride [7784-18-17, A1F., and its trihydrate [15098-87-0] 3 3H2O, have thus far remained to be the only binary fluorides of industrial interest. The nonahydrate [15098-89-2] 3 9H2O, and the monohydrate [12252-28-7, 15621 -55-3], AIF 20, are of only academic curiosity. The monofluoride [13595-82-9], AIF, and the difluoride [13569-23-8], AIF2, have been observed as transient species at high temperatures. 

Germanium forms both a difluoride and a tetrafluoride. It also forms a stable hexafluorogermanate complex ion, GeF that is present in the aqueous acid and a number of salts. 

Xeaoa difluoride behaves as a fluoride ioa doaor toward many metal pentafluorides to form complex salts containing the XeF" and Xe2F" 2 cations (10). In reactions with the pentafluorides of arsenic, antimony, and mthenium, for example, it forms the salts Xe2F" 2AsF(, [21308-45-2], XeF" AsF(, [26024-71-5], [12528-47-1], XeF+Sbp-g [36539-18-1], [17679-45-7], [15364-10-0], [36539-19-2], [26297-25-6],... 

Xenon difluoride [4, 5, 7, 8,10] is a white crystalline material obtained through the combination of fluorine and xenon m the presence of light The reagent is commercially available and possesses a relatively long shelf-life when stored cold (freezer) Xenon difluoride is very effective for small-scale fluormation of alkenes and activated nucleophilic substrates. The reactions are usually conducted between 0 °C and room temperature in chloroform or methylene chloride solutions Hydrogen fluoride catalysis is sometimes helpful Xenon difluoride reacts in a manner that usually involves some complexation between the substrate and reagent followed by the formation of radical and radical cation intermediates... 

Xenon difluoride [55], xenon difluoride complexed with dialkyl sulfides [59], and xenon difluoride intercalated with graphite [90] are all effective reagents for the fluonnalion of acids, enolates, or enols (Table 2)... 

The reagent NSF3 may also react via oxidative addition of an S-F bond to a metal centre to give a complex of the thiazyl difluoride anion [NSF2] , which is readily hydrolyzed to an NSO complex (Scheme 7.3). ... 

The starting point for the synthesis of xenon compounds is the preparation of xenon difluoride, XeF2, and xenon tetrafluoride, XeF4, by heating a mixture of the elements to 400°C at 6 atm. At higher pressures, fluorination proceeds as far as xenon hexafluoride, XeFfi. All three fluorides are crystalline solids (Fig. 15.27). In the gas phase, all are molecular compounds. Solid xenon hexafluoride, however, is ionic, with a complex structure consisting of XeF< + cations bridged by F anions. 

Recently, novel polymethine carbonyl-dyes based on coumarin moiety and their boron difluoride complexes 9a-d and lOa-d [34—36] were evaluated as fluorescent dyes for the detection of native proteins using bovine serum albumin (BSA) as a model protein, and as probes for the nonspecific detection of proteins using a BSA/ sodium dodecyl sulfate (SDS) mixture [37]. Optical properties of these compounds in the absence and presence of BSA, as well as in SDS and BSA/SDS mixture, were measured in Tris-HCl buffer (pH 8.0) (Table 1). 

Studies of fluorescence properties of the dye pair (i.e., boron difluoride complexes dye 9a-d and the nonsubstituted one lOa-d) in the BSA/SDS mixture revealed that coumarins 9b and 10c showed two excitation and emission bands, while other heterocycles showed single bands in the corresponding spectra. For all studied compounds, excitation and emission maxima occurred in the range 405-603 nm and 467-680 nm, respectively. 

This rearrangement has been generalized to also include mangana- and rhena-/3-diketonato boron difluoride complexes [Eq. (8)] (45). A diagnostic indication of the formation of allyl products 36 is the observation of the... 

Since the discovery of the first noble gas compound, Xe PtF (Bartlett, 1962), a number of compounds of krypton, xenon, and radon have been prepared. Xenon has been shown to have a very rich chemistry, encompassing simple fluorides, XeF2> XeF, and XeF oxides, XeO and XeO oxyf luorides, XeOF2> XeOF, and Xe02 2 perxenates perchlorates fluorosulfates and many adducts with Lewis acids and bases (Bartlett and Sladky, 1973). Krypton compounds are less stable than xenon compounds, hence only about a dozen have been prepared KrF and derivatives of KrF2> such as KrF+SbF, KrF+VF, and KrF+Ta2F11. The chemistry of radon has been studied by radioactive tracer methods, since there are no stable isotopes of this element, and it has been deduced that radon also forms a difluoride and several complex salts. In this paper, some of the methods of preparation and properties of radon compounds are described. For further information concerning the chemistry, the reader is referred to a recent review (Stein, 1983). 

Radon difluoride is quantitatively reduced to elemental radon by water in a reaction which is analogous to the reactions of krypton difluoride and xenon difluoride with water. Complex salts of radon also hydrolyze in this fashion. 

Kroll process, 13 84-85 15 337 17 140 in titanium manufacture, 24 851-853 Kroll zirconium reduction process, 26 631 KRW gasifier, 6 797-798, 828 Krypton (Kr), 17 344 commercial, 17 368t complex salts of, 17 333-334 doubly ionized, 14 685 hydroquinone clathrate of, 14 183 in light sources, 17 371-372 from nuclear power plants, 17 362 physical properties of, 17 350 Krypton-85, 17 375, 376 Krypton compounds, 17 333-334 Krypton derivatives, 17 334 Krypton difluoride, 17 333, 336 uses for, 17 336... 

The ability of quaternary ammonium halides to form weakly H-bonded complex ion-pairs with acids is well established, as illustrated by the stability of quaternary ammonium hydrogen difluoride and dihydrogen trifluorides [e.g. 60] and the extractability of halogen acids [61]. It has also been shown that weaker acids, such as hypochlorous acid, carboxylic acids, phenols, alcohols and hydrogen peroxide [61-64] also form complex ion-pairs. Such ion-pairs can often be beneficial in phase-transfer reactions, but the lipophilic nature of H-bonded complex ion-pairs with oxy acids, e.g. [Q+X HOAr] or [Q+X HO.CO.R], inhibits O-alkylation reactions necessitating the maintenance of the aqueous phase at pH > 7.0 with sodium or potassium carbonate to ensure effective formation of ethers or esterification [49,64]. 

The separated proteins were transferred to a polyvinylidene difluoride membrane, and nonspecific IgC binding sites were blocked by incubation with 5% nonfat dry milk for 1 h at room temperature. The membranes were then incubated overnight at 4°C with primary antibodies. Immune complexes were detected by enhanced chemiluminescence (Amersham Biosciences). 

Reaction of fluorine with an aqueous alkah solution is complex and depends on reaction conditions. A major product of such reaction is oxygen difluoride, OF2. In cold alkah solution, the products constitute metal fluoride, oxygen difluoride, water, and oxygen ... 

Krypton is an inert gas element. Its closed-shell, stable octet electron configuration allows zero reactivity with practically any substance. Only a few types of compounds, complexes, and clathrates have been synthesized, mostly with fluorine, the most electronegative element. The most notable is krypton difluoride, KrF2 [13773-81-4], which also forms complex salts such as Kr2F3+AsFe [52721-23-0] and KrF+PtFF [52707-25-2]. These compounds are unstable at ambient conditions. Krypton also forms clathrates with phenol and hydroquinone. Such interstitial substances are thermodynamicahy unstable and have irregular stoichiometric compositions (See Argon clathrates). 

Krypton difluoride forms complexes with fluorides of many metals, such as arsenic, antimony, tantalum, niobium, gold, and platinum. 

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