Tetrabutylammonium salt

Cadmium, tris(diethyldithiocarbamato)-tetrabutylammonium salt structure, 1, 62... 

Acid (0.78 M), neutralized to 25% Pt-anode, 0.25 A/cm Alcohol, ester, ether and acetamide according to solvent Sodium salt Tetrabutylammonium-salt... 

For the tetrabutylammonium salts of substituted acetate the quarter wave potentials have been determined by chronopotentiometry in acetonitrile. The ease of oxidation, as reflected in the Ej -values, decreases with increasing strength of the acid [88]. 

The sodium and potassium salts of glutaconaldehyde are soluble only in polar solvents such as water, dimethyl sulfoxide, N,N-dimethylformamide, pyridine, and methanol. However, the stable tetrabutylammonium salt is soluble in relatively nonpolar solvents such as chloroform and ethyl acetate. It may be prepared from the potassium salt in the following manner. In a 1-1. Erlenmeyer flask equipped with a magnetic stirring bar are placed a solution of 13.6g. (0.1 mole) of crude glutaconaldehyde potassium salt in 200 ml. of water and a solution of 33.9 g. (0.1 mole) of tetrabutyl-ammonium hydrogen sulfate in 200 ml. of ice-cold water, the pH of wliich was adjusted to 10 by adding aqueous 2M sodium hydroxide. 

With Roustan et al. using the sodium salt of the Hieber anion 76-Na, the procedure was improved by Xu and Zhou in 1987 when they introduced the corresponding shelf-stable tetrabutylammonium salt 76-[Bu4N] which is available from Fe(CO)5 78, NaN02 and Bu4NBr (Scheme 17) [61,62]. As well as discovered by Roustan they obtained the substitution products with an ipso-preference (Scheme 16) albeit in a significantly lower yield. In order to maintain the catalytic activity of the product, the reactions were performed under CO-gas atmosphere. 

In a similar manner, the diffusion of hexane into dichloromethane solutions containing mixtures of the alkylammonium salts of bromide and the olefinic acceptors o-CA and TCNE result in the formation of brown-red crystals [23]. X-ray analysis reveals the (1 1) complex of bromide with o-CA, in which the anion is located over the center of the C - C bond of the acceptor moiety (Fig. 15b) and Br - C contacts are shortened by as much as 0.6 A relative to the sum of van der Waals radii (Table 3). In bromide complexes with TCNE, the location of the anion relative to the acceptor is variable. In fact, a 2 1 complex [(Br )2,TCNE] is isolated in which both anions reside over the olefinic bond when the tetraethylammonium salt of bromide is used. In comparison, if the tetrapropyl- or tetrabutylammonium salts of the same anion are employed, the (1 1) complexes [Br ,TCNE] are formed in which the bromide donors are shifted toward the cyano substituents (Fig. 15a). In both cases however, the short intermolecular separations that are characteris-... 

Figure 10. Slurry electrochemical voltage spectroscopy experiments with tetragonal [Si(Pc)0]n and various perfluoroalkyl-sulfonates (as the tetrabutylammonium salts in acetonitrile).

Davies, S. G. et al., J. Organomet. Chem., 1990, 386(2), 195 This compound is air sensitive and decomposes explosively. Use of the more stable tetrabutylammonium salt as a reagent for carbonylation of alkyl halides is recommended. 

Several tetrabutylammonium salts of the [LnPc2]1 complexes were prepared, and the crystal structures were analysed [166,177-184]. The analysed structures... 

Energetic electron transfer reactions between electrochemically generated, shortlived, radical cations and anions of polyaromatic hydrocarbons are often accompanied by the emission of light, due to the formation of excited species. Such ECL reactions are carried out in organic solvents such as dimethylformamide or acetonitrile, with typically a tetrabutylammonium salt as a supporting electrolyte. The general mechanism proposed for these reactions is as follows. 

The conversion of squaraine 19a to the rotaxane 18 D 19a causes a modest red-shift only in both absorption (10 nm) and emission (7 nm) but an approximately threefold decrease in quantum yield. The addition of two triazole rings (dye 19b) did not significantly alter the quantum yield of 17b (Table 4). A macrocycle-induced quenching effect was verified by fluorescence titration experiments adding aliquots of 18 to a solution of squaraine 17b in methylene chloride [58]. Treatment of the 18 d 17b psuedorotaxane system with the tetrabutylammonium salts of chloride, acetate, or benzoate leads to the displacement of squaraine 17b from the macrocyclic cavity and the nearly complete restoration of its fluorescence intensity. The 18-induced quenching of 17b does not support the utility of this system as a bioimaging probe however, the pseudorotaxane system 18 Z> 17b acts as an effective and selective anion sensor with NIR fluorescence. 

Obtained in acetonitrile solution containing 0.2 mol dm-3 BuJNBF4 as supporting electrolyte. Solutions were 1 X 10 3moldm-3 in ligand and potentials were obtained with reference to Ag/Ag+ electrode. "Cathodic shift in reduction potential produced by presence of anions (up to 10 equiv) added as their tetrabutylammonium salts. 

Obtained in MeCN solution containing 0.1 mol dm 3 Bu°NBF4 as supporting electrolyte. Solutions were 1 x 10 3 mol dm 3 in compound and potentials were determined with reference to an Ag/Ag+ electrode at 21 1°C, 50 mV s scan rate. > p, and represent the anodic and cathodic peak potentials. Cathodic shifts in the metallocene redox couples produced by the presence of anion (5 equiv) added as their tetrabutylammonium salts. As the concentration of the anion increased, the cathodic current peak potential of the ferrocene/ferTOcenium redox couple began to exhibit the features of an EC mechanism. 

DMPO is more difficult to oxidize than PBN by about 0.2 V (Table 1) and is therefore expected to engage in spin trapping via its radical cation with greater difficulty, as found for the 0sCl6-4-N02-PBN reaction. Only acetate ion, tetramethylsuccinimide ion and triethyl phosphite gave the corresponding adducts upon oxidation with TBPA + in dichloromethane in the presence of DMPO, whereas fluoride ion gave the hydroxyl adduct. The latter was probably formed from water available from the unavoidable hydration shell around fluoride ion in its tetrabutylammonium salt. 

When the monosodium salts of uracil and similar pyrimidines react with diphenyl phosphorochloridate, phosphorylation takes place on oxygen unless other suitable nucleophilic centres are present and free.69 The reaction between the sodium salt of a 1,3-dicarbonyl compound and diethyl phosphorochloridothionate yields the Z-vinylphosphorothionate if the tetrabutylammonium salt is employed, the product has E geometry. This phenomenon has been interpreted in terms of the shape of the... 

Phosphorylation of phenolate anions with dimethyl phosphorochloridothionate in water-dichloromethane systems normally gives large amounts of dithiopyrophos-phate because of extensive hydrolysis of the phosphorus chloride, but in the presence of tetrabutylammonium salts and 1 % imidazole, phosphorylation of the phenolate anion is complete. The explanation lies in an evident combination of activation of acylating agent (by imidazole) and of nucleophile (by phase-transfer catalysis).71... 

The deprotection step and subsequent purification are equally facile. Exposure of a TiPS-ethynyl-protected dendrimer to tetrabutylammonium fluoride in THE results in a quantitative reaction within 2 h. The tetrabutylammonium salts can be removed by siHca plug filtration rendering pure product, and the obtained yields are higher than 95%. If deprotection is effected instead with ammonium fluoride and catalytic amounts of tetrabutylammonium fluoride, even silica plug filtration is unnecessary. 

Bromonaphthalene does not react with benzenethiol (thiophenol) salts. However, if electric current is passed through a solution containing 1-bromonaphthalene, the tetrabutylammonium salt of thiophenol, and DMSO, then l-(phenylthio)naphthalene is produced in 60% yield. When the reaction is conducted in acetonitrile, it leads to naphthalene above all (Pinson and Saveant 1978, Saveant 1980, Amatore et al. 1982). In the electrochemically provoked reaction, it is sufficient to set up the potential difference corresponding to the initial current of the reduction wave to transform 1-bromonaphtahalene into 1-naphthyl radical. The difference in the consumption of electricity is rather remarkable In the absence of thiophenolate, bromonaphthalene is reduced, accepting two electrons per molecule in the presence of thiophenolate, 1-bromonaphthalene is reduced accepting two electrons for every ten molecules. The reaction with the thiophenolate ion is catalyzed by electric current and takes a reaction path shown in Scheme 5.2. 

In the case of the free 9-acetylanthracene anion-radical, the spin density on the carbonyl group is lower than that in the para position (position 10) by a factor of 5. The formation of the tail-to-tail dimer should be expected. Actually, preparative reduction of 9-acetylanthracene in DMF against the background of a tetrabutylammonium salt results in the tail-to-tail dimer with the yield of 70%. Addition of a lithium salt, however, decreases the dimer yield to 45% (Guftyai et al. 1987b, Mendkovich et al. 1991). 

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