Tetraalkyl ammonium cyanides

Alternatively, metal-cyanide complexes have been formed by the reaction of a metal halide with an anionic cyanide. The addition of alkali metal cyanides to aqueous solutions of transition metal halides has been used to form many homoleptic metal cyanides [M(CN) ], as illustrated in Equation 3.54. Alternatively, the reactions of tetraalkyl ammonium cyanides, which are soluble in a range of organic solvents, have been used to prepare low-valent metal-cyanide complexes (Equation 3.55). ... 

The protection of carbonyl functions by reaction with trimethylsilyl cyanide to form the cyanohydrin trimethylsilyl ethers is subject to catalysis by potassium cyanide in the presence of 18-crown-6, tetrabutylammonium cyanide or resin bound tetraalkyl-ammonium cyanide [27, 29]. The nucleophilic cyanide ion is believed to attack the carbonyl yielding a cyanohydrin anion. This anion is silylated by trimethylsilyl cyanide with generation of an equivalent of cyanide anion. The sequence is shown in equation 7.13. Accordingly, 3-pentanone and 4- -butylcyclohexanone are cyanosil-... 

Anionic catalysts work by coordination to the silicon atom they are needed in only small amounts ( 0.01% based on the initiator) and are used preferably for methacryhc monomers [232]. The anionic moiety comprises fluoride, azide, and cyanide, but also carboxylates, phenolates, sulfmates, phophinates, nitrite, and cyanates [232,236,237]. These anions are often used in combination with their corresponding adds as biacetate, H(CH3COO)J or bifluoride, (HF2) . The counterions are usually tetraalkyl ammonium or tris(dimethylamino)sulfonium, [(CH3)2N]3S" (TAS). The most widely used catalysts are TASHF2 and TASF2SiMe3 [239]. To accelerate the reactivity of potassium bifluoride, KHF2, a crown ether (18-crown-6)-supported polymerization has been carried out [240]. 

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