Potassium tetra

Potassium tetra(l-indolyl)boron (419) was obtained as an infusible white solid by boiling an ethereal solution of indole magnesium bromide with potassium fluoroborate under reflux for 6 hours. 

FIGURE 5.10 Synthesis of a polyethyleneglycol-polystyrene graft polymer by etherification of Merrifield resin using potassium tetra(oxyethylene) oxide, followed by extension of the chain by reaction of the potassium salt, which is present as the crown ether.21 In several TentaGel resins, the connecting bond is an ethyl ether that is more acid-stable than the benzyl ether. 

The formulas for compounds described in volume 34 are entered in alphabetical order. They represent the total composition of the compounds, e.g., BF24KC38H21 for potassium tetra-3,5-bis(trifluoro-methyl)phenylborate. The elements in the formulas are arranged in alphabetical order, with carbon and hydrogen listed last. All formulas are permuted on the symbols other than carbon and hydrogen representing organic groups in coordination compounds. Thus potassium tetra-3,5-bis(trifluoro-methyl)phenylborate can be found under B, F, and K in this index. 

Wood, R. M., Aboud, K. A., Palenik, R. C., and Palenik, G. J. (2000). Bond valence sums in coordination chemistry. Calculation of the oxidation state of chromium complexes containing only Cr-O bonds and a redetermination of the crystal structure of potassium tetra(peroxo)chromate(V). Inorg. Chem. 

Tetrahydrofuran is partially fluorinated over cobalt(III) fluoride81 and potassium tetra-fluorocobaltate(III).82 With cobalt(III) fluoride at 100-1 IO C,27 products are obtained with an overall yield of about 50 60%. Most are polyfluorooxolanes 2-4, and the rest (13% of the product mixture) polyfluoropropanes. The major products are 2 (15%), 3 (29%), and 4 (29%) (since the various stereoisomers are equilibrated at the positions next to oxygen in the fluorination process, the total percentages for each set of constitutional isomers are shown, and not the percentages for each stereoisomer). 

Dioxane is partially fluorinated84 over cobalt(lll) fluoride and potassium tetra-fluorocobaltate(III). With cobalt(III) fluoride at 100°C yields are poor (ca. 15%), and the major products are 7-10 (as with the oxolanes, equilibrium occurs between the stereoisomers during the fluorination). With potassium tetrafluorocobaltate(III) at 220°C, compound 11 comprises 61 % of the product mixture in an overall yield of about 40%. 

Esters and acid fluorides give88 product mixtures very similar to those produced from ketones. Cobalt(III) fluoride again causes complete degradation, but potassium tetrafluoro-cobaltate(lll) gives polyfluoro acid fluorides, which are isolated by conversion to their ethyl esters yields are poor (ca. 20%) in all cases. Methyl propanoate reacts with potassium tetra-fluorocobaltate(III) at 350 CC to give a 5 2 2 mixture of ethyl 2,2-difluoropropanoate, ethyl... 

Pyridine and the methylpyridines are fluorinated over cobalt(III) fluoride, potassium tetra-fluorocobaltate(III) and cesium tetrafluorocobaltate(III). Only in the cesium tetrafluorocobalt-ate(III) reactions are significant quantities of polyfluoropyridines and -methylpyridines isolated. 

The fluorination of propanonitrile" was very reminiscent of methyl propanoate and pro-panoyl fluoride (Section 25.1.1.3.), in that replacement of the cc-fluorines is favored over the fi. Again cobalt(III) fluoride (205°C) and potassium tetrafluorocobaltate(III) (335°C) give similar product mixtures albeit at different temperatures. Yields are better over potassium tetra-fluorocobaltate(III) (> 40%) and the major product is 2-fluoropropanonitrile followed by 2,2-di-, 2,2,3-tri- and 2,2,3,3-tetrafluoropropanonitrile. 

The main products from the reaction of hexachlorobuta-1,3-diene112 and potassium tetra-fluorocobaltate(III) at 180-200LC are l,2,3-trichloro-l,l,4,4-tetrafluorobut-2-ene (20%) and l,2,3-trichloro-l,l,4,4,4-pentafluorobut-2-ene (20%). 

Alcoholic (CH3OH or C2H5OH) or H20/THF solutions of potassium tetra-carbonylhydridoferrate(l — ) salts are readily prepared by the rapid and quantitative reaction of Fe(CO)5 with 2 equiv of KOH following a procedure described in Inorganic Syntheses.15... 

The operation of the mismatch effects may be seen to best advantage when a range of products is possible from a single reactant or set of reactants. The reaction of ethylene oxide with metal salts results in the formation of crown ethers (Fig. 6-30). Obviously, a whole range of different cyclic oligomers and acyclic polymers could be formed from ethylene oxide. If we specifically wanted to obtain 18-crown-6, with a hole size of about 1.4 A, we would expect to use a potassium ion as template (r = 1.38 A). In fact, 18-crown-6 is obtained in good yield from the reaction of ethylene oxide with potassium tetra-fluoroboratc. In contrast, if we wanted 12-crown-4, with a hole size of about 0.8 A, it... 

It is a complex between platinum metal and ethylene, obtained when ethylene is passed through aqueous solution of potassium tetra chlroplatinate. 

Other compounds of the selenophene series such as potassium tetra(a-selenienyl)borate (23), obtained by interaction of a-selenienyl-magnesium iodide with potassium tetrafluoroborate, precipitate rubidium ions and, more completely, cesium and quaternary ammonium ions from water solutions and can be used as analytical reactants for those ions.81... 

The first report of cyclometalation in organopalladium chemistry was the reaction of azobenzene with potassium tetra-chloropalladate to give the C,N-chelate (22) (equation 66). This reaction is characteristic of most cyclometalation reactions with palladium, in that it takes place with Pd in protic solvents with the loss of HCl, and the resulting chelate is stable to air and moisture. 

Potassium Tetra-uranate, K2U4OJ3.5H2O, separates as a yellow powder on evaporating a solution of potassium uranyl acetate. 

Twenty-seven grams (0.038 mol) of potassium tetra-oxalato-di-Ai-hydroxocobalate(III) 3-hydrate is suspended... 

Potassium tetra-methyl ammonium acetic acid iodide salt)... 

Reduction of aqueous solutions of potassium tetra-cyanonickelate(II), e.g., by hydroxylamine, potassium amalgam, or tin and sodium hydroxide, yields a red solu-... 

Reaction of CsF with B(OMe)3 in anhydrous EtOH forms Cs[BF(OMe)3], characterized by elemental analysis, F n.m.r., and i.r. spectroscopy. It dissociates to the original components on heating above 115 Potassium tetra-acetatoborate forms monoclinic crystals, space group P2i/n. The structure is made up of slightly distorted B—O tetrahedra, held together by... 

The photo-oxidation of sulphur to H2SO4 by hydrogen peroxide takes place in aqueous tetrachloromethane and is intensified by methanol. The reaction of potassium tetracyanonickelate(ii) with molten sulphur, and with potassium tetra-sulphide in molten sulphur, has been studied. The physical adsorption of SO2, SFg, CO2, N2, Ar, and neopentane on rhombic sulphur has been reported. The chemical forms of trace quantities of sulphur in arsenic trichloride have been identified by radiochemical methods as elemental sulphur and SO2CI2. The reactions of sulphur vapour with lanthanide oxides (at 1050—1120 C), oxycarbo-nates, or oxalates (at 700 °C) has been shown to give the oxysulphide. The reactions are thought to proceed via the lanthanyl ion [LnO]" ... 

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