Sodium tetrafluoroborate

Pentamethylcyclopentadienyl substituted boron complexes arc obtamed by the reaction of the pentamethylcyclopentadienyl anion with boron tnfluonde [109] (Table 27) Similarly, the Gngnard reagent prepared from 3,5-bis(tnfluorometh-yl)iodobenzene reacts with sodium tetrafluoroborate to form the phase-transfer eatalyst 2 under anhydrous eonditions [110] (equation 87)... 

The N-coordinated compound [AuCljL] (L= l-ethyl-2-phenylimidazole) with silver tetrafluoroborate gives the cycloaurated species 102, which on further reaction with triphenylphosphine and sodium tetrafluoroborate or ammonium hexafluorophosphate forms the cationic complexes 103 (X = BF., PF,) (00JCS(D)271). 

E.22 (a) How many CaH2 formula units are present in 5.294 g of CaH2 (b) Determine the mass of 6.25 X 1024 formula units of NaBF4, sodium tetrafluoroborate. (c) Calculate the amount (in moles) of 9.54 X 1021 formula units of Cel3, cerium(III) iodide, a bright yellow, water-soluble solid. 

H.12 The reaction of boron trifluoride, BF,(g), with sodium borohydride, NaBH4(s), leads to the formation of sodium tetrafluoroborate, NaBF4(s), and diborane gas, B2Hfc(g). The diborane reacts with the oxygen in air, forming boron oxide, B20 j(s), and water. Write the two balanced equations leading to the formation of boron oxide. 

In 2002 Mehnert and co-workers were the first to apply SILP-catalysis to Rh-catalysed hydroformylation [74], They described in detail the preparation of a surface modified silica gel with a covalently anchored ionic liquid fragment (Scheme 7.7). The complex N-3-(3-triethoxysilylpropyl)-4,5-dihydroimidazole was reacted with 1-chlorobutane to give the complex l-butyl-3-(3-triethoxysilylpropyl)- 4,5-dihydroimidazolium chloride. The latter was further treated with either sodium tetrafluoroborate or sodium hexafluorophosphate in acetonitrile to introduce the desired anion. In the immobilisation step, pre-treated silica gel was refluxed with a chloroform solution of the functionalised ionic liquid to undergo a condensation reaction giving the modified support material. Treatment of the obtained monolayer of ionic liquid with additional ionic liquid resulted in a multiple layer of free ionic liquid on the support. 

Compounds 133, prepared by the condensation of benzotriazole with aldehydes R HO (R1 = H, Pr or Ph) and 7V-octylaminoacetonitrile, react with sodium tetrafluoroborate to give the cyanomethyl derivatives 134. The latter are de-cyanomethylated by the action of copper(II) sulphate. Treatment of 133 with Grignard reagents affords the analogues 135 (R2 = Ph or PhCH2) and thence the secondary amines 136130. 

Addition of sodium tetrafluoroborate to 2d led to the carbodiphosphor-ane 77 possessing a P-H bond, which was isolated in 70% yield.31 Although 77 is thermally quite stable as a solid (mp 116°C), it slowly rearranges in solution at room temperature (1 week) into its isomeric phosphorus ylide 78. This last result was not surprising, since calculations predicted 78 to be 19 kcal/mol more stable than 77.16... 

Other methods for the generation of cation-radicals should also be mentioned. Mesoionic 5,5 -azinobis(l,3-diphenyltetrazole) and related mesoionic compounds give cation-radicals on oxidation by lead tetraacetate. The reaction proceeds in the presence of sodium tetrafluoroborate. The tetra-fluoroborate cation-radical salt is stable and can be purified by column chromatography on silica gel and stored in air for several months without appreciable decomposition (Araki et al. 1999). The cation-radicals of A,A -dimethyldiazines are produced by usual oxidation of the parent diazine... 

Potassium tetrafluoroborate (Strem Chemicals Inc.) was used as received. Sodium tetrafluoroborate can be also used although it is much more expensive. 

Nitration also may be achieved noncatalytically without using AICI3. For example, sodium tetrafluoroborate may be added to benzene to yield nitroben-... 

Thiazolium ion based ionic liquids (OIL) have been used to promote the benzoin condensation of benzaldehyde. 4- And 5-methylthiazoles are readily alkylated with n-butyl bromide to give the corresponding bromide salt. Anion exchange with sodium tetrafluoroborate gave the tetrafluoroborate salt 53 as a stable yellow orange oil. When activated with a small quantity of triethylamine (5 mol%) the oil promotes the coupling of benzaldehyde to benzoin <99TL1621>. 

On the other hand, 1-fluoropyridinium tetrafluoroborate has been isolated from the reaction performed in the presence of sodium tetrafluoroborate.34 These investigations have been extended to the fluorination of various amino derivatives and in some cases A -fluoro products were isolated in good yield, c.g. formation of 26.34... 

Preparation and Reactions of Sodium Tetrafluoroborate and Potassium Tetrafluoroborate... 

Generally, sodium nitrite is the nitrosating agent. In this case, sodium tetrafluoroborate is produced together with the diazonium tetrafluoroborate and must be discarded, which can be a drawback on an industrial scale. 

Nitro substituents and heterocyclic nitrogen influence not only the yield of fluorodediazoniation but also the rate of decomposition which, in these cases, is too high to perform the reaction on a multigram scale. Some explosions have been reported. Thus, the decomposition of nitro-substituted or heterocyclic diazonium tetrafluoroborates is usually controlled by three-to fivefold dilution of these substrates in inert solids, such as acid-washed sand,113 218 Kiesel-guhr,3 sodium carbonate,3 barium sulfate,217 sodium fluoride,216 or sodium tetrafluoroborate.3 This modified technique has been generalized to the decomposition of all kinds of diazonium tetrafluoroborates under safe conditions, even on rather large scales. 

Sodium tetrafluoroborate [13755-29-8] M 109.8. Recrystd from anhydrous MeOH and dried in a vacuum at 70° for 16h. It is affected by moisture. [Delville et al. JACS 109 7293 1987]. 

Recently, the air- and water-stable combinations of l-n-butyl-3-methyl-imidazolium chloride with sodium tetrafluoroborate or sodium hexafluoro-phosphate have been prepared. The rhodium complexes [RhCl(PPh3)3] and [Rh(COD)2](BF4) are completely soluble in these ionic liquids and catalyze the hydrogenation of cyclohexene in a typical two-phase reaction with numbers of turnovers of up to 6000 (131). 

Substituted imidazole 1-oxides 263 upon treatment with dimethyl or diethyl sulfate furnish l-alkoxy-3-subtituted imidazolium salts 283 that were converted to the tetrafluoroborate 283 (A- = BF4 ) or hexafluorophos-phates 283 (A = PF6-) by treatment with sodium tetrafluoroborate or hexa-fluorophosphate (2007ZN(A)295). The tetrafluoroborates 283 (A = BF4 ) reacted with cyanide ion to give 2-cyanoimidazoles 285 (1975JCS(P1)275). The reaction probably follows a mechanism similar to that suggested to be operative in the pyrazole series encompassing O-alkylation succeeded by nucleophilic addition and elimination of methanol (Scheme 85). 

Reduction of [Mo(CO)2(bpy)2] using sodium amalgam or sodium naphthalenide gives paramagnetic [Mo(CO)2(bpy)2] in dimethoxyethane (81JOM(218)C31). Oxidation of [Mo(CO)2(bpy)2] using silver tetrafluoroborate in acetonitrile or aluminum chloride in methylene chloride and followed by sodium tetrafluoroborate gives... 

The solution becomes orange-red, and gas is evolved. Meth-anesulfonic acid is added to keep the pH at 2 to 3. The solution is allowed to stand, with additions of methanesulfonic acid to keep the pH at 2 to 3, until the solution becomes yellow. Solid sodium chloride is added until precipitation of [Ru(NH8)6N2]Cl2 is complete. The crude product is removed by filtration, washed with alcohol and acetone, and air-dried. It is recrystallized by dissolving in water, filtering the solution, and reprecipitating the product with solid sodium chloride. Two recrystallizations by this method yield a product which is almost white (very pale yellow). The other salts are prepared by dissolving the purified chloride salt in water and adding saturated, filtered solutions of potassium iodide or bromide, sodium tetrafluoroborate, or ammonium hexafluorophosphate until precipitation of the desired salt is complete. The products are collected by filtration, washed with a little water, alcohol, and acetone, and then air-dried. Yield is 0.5 g., 33% for the pale yellow iodide salt. Anal. Calcd. for [Ru(NH8)8N2]l2 NH, 18.19 N , 5.98 I, 54.27. Found NH8, 18.04 N, 5.35 I, 54.05. 

A 1-g. (4.75-mmole) sample of C8HsFe(CO)2Cl is placed in a small Schlenk tube (see page 10) of about 50-ml. volume. A 7-ml. sample of freshly distilled BF3-0(C2H8)2 is added, and the solution is heated to 40-50°C. for 1 hours. During that time the color changes from light red to deep purple. The reaction mixture is then frozen in liquid nitrogen, and 10 ml. of a saturated solution of sodium tetrafluoroborate is added. The... 

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