Tetramethylammonium salts

The tetramethylammonium salt [Me4N][NSO] is obtained by cation exchange between M[NSO] (M = Rb, Cs) and tetramethylammonium chloride in liquid ammonia. An X-ray structural determination reveals approximately equal bond lengths of 1.43 and 1.44 A for the S-N and S-O bonds, respectively, and a bond angle characteristic bands in the IR spectrum at ca. 1270-1280, 985-1000 and 505-530 cm , corresponding to o(S-N), o(S-O) and (5(NSO), respectively. Ab initio molecular orbital calculations, including a correlation energy correction, indicate that the [NSO] anion is more stable than the isomer [SNO] by at least 9.1 kcal mol . ... 

Platosamminc chloride — see Rcisct s second chloride Platosemidiammine chloride — see Peyrone s salt Plumbacarboranes. 3,219 Plumbate, diphenyltris(acetato)-tetramethylammonium salts structure, 1,90 Plumbates. 3, 204 Plumbocene... 

The KB9C2H10(CH3)2 recovered from the ethanol solution is dissolved in 150 ml. of water, and a solution of 22 g. of trimethylammonium chloride in 100 ml. of water is added slowly with vigorous stirring. The precipitated salt is isolated by filtration, washed once with 50 ml. of cold water, and dried in vacuum over phosphorus(Y) oxide. The yield of (CH3)3NHB9C2Hio-(CH3)2 is 37.8 g. (98%). To purify the salt by crystallization, a boiling solution of 38 g. of the salt in 2 1. of water is allowed to cool slowly to 0°. Eighty per cent of the material is recovered in the first crop. Successive crops of the trimethylammonium salt may be obtained, or the anion may be recovered as the less soluble tetramethylammonium salt by addition of an aqueous solution of tetramethylammonium chloride to the mother liquor. The tetramethylammonium salt may be recrystallized from an ethanol-water solution. 

The tetramethylammonium salt is very soluble in acetone and acetonitrile, sparingly soluble in methylene chloride and boiling methanol, and insoluble in organic solvents such as benzene, hexane, and diethyl ether. The color of its solutions... 

Analogously the ethoxy cation 75 was found to be valuable for the synthesis of calicenes when combined with cyclopentadienyl anions93 Hexaphenylcalicene (100) was prepared by this route from tetraphenylcyclopentadienyl-Li94,76) and the highly polar dicyanocalicene 10195 from the tetramethylammonium salt of dicyano-cyclopentadiene. 

The bent [NSO]- anion (36) in the tetramethylammonium salt [Me4N][NSO] has approximately equal S-N and S-O bond lengths of 1.43 and 1.44 A, respectively, and a bond angle transition-metal and main group element thionyl imides by metathetical reactions.70... 

Harmon and Lovelace (1982) studied the ir spectrum of -toluidinium bifluoride and tetramethylammonium bifluoride and concluded that the hydrogen bonds are different from that of KHF. The first is different because it is known to be unsymmetrical, but the second was claimed to be even stronger than the hydrogen bond in KHFj. For the tetramethylammonium salts of HFj and DFj the isotope ratios were 1.40 (V2) and 1.41 (Vj). Clearly, the final word on the vibrational analysis of FHF has still to be written. Calculations of ionic force fields based on ir data have been carried out (Matsui et al., 1986), but since these are based on V3 it is probably unwise to read too much into them. 

Consequently, it was deemed desirable to operate in a very weakly coordinating solvent if possible. Since acetonitrile is a much poorer donor solvent than glacial acetic acid, and since the tetramethylammonium salt of the chromium (III) complex is soluble in acetonitrile, this appeared to be an ideal solvent for running ligand reactions. However, initial experiments indicated that neither acetic anhydride nor acetyl chloride would acetylate the complex in this solvent. 

The reactions of the conjugate base of 2-nitropropane, used as the lithium or tetraalkylammonium salt, have been described for a number of 2-nitro-5-X-thiophenes (X = H, I, NOz, CMe2N02) and for 2,4-dinitrothio-phene. They generally display a complex pattern leading to several products. Only for 2-nitrothiophene and 2,4-dinitrothiophene has evidence for the formation of (7-adducts 137 and 138, respectively, been recorded.178 Adduct 138 has in fact been isolated as the tetramethylammonium salt and characterized by elemental analysis and NMR spectroscopy, whereas 137 has been detected in situ. The NMR data are reported in Table XX. H-NMR chemical shifts... 

Phenanthrene was analyzed directly by fluorescence with excitation at 365 nm and emission at 394 nm and quantified by comparison to a standard curve. 5-Chlorouracil was analyzed directly by absorbance at 270 nm. Attempts to determine 5-chlorouracil as the pyrolysis product of its tetramethylammonium salt (11) were unsuccessful. Hypochlorite was determined by the ferrous-N,N-diethyl-p-phenylenediamine titration method (12). 

The increase in the value of JFF in passing from the neutral molecule 244a to the anion 360 (tetramethylammonium salt) is worthy of note. The product obtained from methylation of 244a with diazomethane (Scheme 16, Section IV,C,2) was assigned329 structure 472 (3-methyl), not 368 (1-methyl), on the basis of the 6JHF coupling constant. 

Nitro-4-methoxyaniline has been prepared by heating nitro-hydroquinone dimethyl ether with aqueous ammonia 2 by heating the tetramethylammonium salt of 3-nitro-4-aminophenol 3 by the hydrolysis of 2-nitro-4-methoxyacetanilide la with alcoholic potassium hydroxide 11 lc or hydrochloric acid ld and by the hydrolysis of the />-toluenesul fonamide,4 the 3-nitrobenzenesul-fonamide,5 the 3-nitro-/>-toIuenesulfonamide,3 and the acetyl derivative of the />-toluenesulfonamide6 of 2-nitro-4-methoxyani-line with concentrated sulfuric acid. 

Methylated derivatives of the barbiturates have been preferred by many workers for chromatographic separation. Barbiturates can be methylated in the flash heater of a chromatograph by injecting a methanol solution of their tetramethylammonium salts. Tri-methylanilinium hydroxide has also been used, with the advantage that lower injection port temperatures may be used. 

The crystal structure of the tetramethylammonium salt of Ag(NCO)J has been determined.139 The anion was approximately linear (N—Ag—N bond angle 177.2°) and the Ag—N bond lengths were 201.5 and 206.8 pm. 

K for 24 h. The crystalline material was recovered after suspension in 5% NaOH solution by filtration (Kuznicki, 1989, 1990 Kuznicki et al., 1991a, 1991b, 1991c, 1993). The synthesis of ETS-10 has also been carried out by the use of tetramethylammonium salts, with a significant acceleration of crystal growth (Valtchev et al., 1994). These titanium silicates contain Tilv in octahedral coordination and do not have the catalytic properties of the titanium silicates discussed previously (see Sections III and VI). 

They carried this reaction out under pseudo-first-order conditions (excess of 2-nitro-propanate ions) in acetonitrile at 25°C, under argon atmosphere in a light-protecting vessel. The 2-nitropropanate ion was introduced as the tetramethylammonium salt. Two products were formed (Scheme 8-10). One of the products was the expected C-substituted compound. The other was an unstable species, which decomposed into the 4-nitrocumyl alcohol during workup and was ascribed to O-substitution. In 1975, Komblum had obtained the same products. He considered the C-substitution as an SRN1 reaction and the O-substi-... 

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