Cerium iodide

Organocerium reagents are prepared in situ by the reaction of organolithium compounds with anhydrous cerium chloride or cerium iodide, as shown in equation (1). " A variety of organolithium compounds can be employed, including alkyl-, allyl-, alkenyl- and alkynyl-lithiums, which are all converted to the corresponding cerium reagents. 

CaS03 CALCIUM SULFITE 482 Cel3[g] CERIUM IODIDE (GAS) 517... 

Allyl iodide reacts in situ with cerium amalgam to generate allyl cerium iodide, which in turn reacts with ketones to give homoallylic alcohols to good yields (Imamoto et al., 1981). 

Reaction conditions called for mixing a THF solution of the a-haloketone with an aqueous mixture of cerium(III) sulfate and sodium iodide to produce the cerium iodide intermediate. 

It is interesting, that phenyl cerium iodide obtained from Phi and Ce in the presence of Lil, unlike "common" PhCel, reacts with 1,2,2-trifluorostyrene and gives a mixture of cis-and trans-isomQTS of PhC(F)=C(F)CH(Ph)(H2)30H after hydrolysis [67]. In this case high reactive complexes of ate-iypQ containing lowvalent cerium are proposed to be formed ... 

Most of the known monocyclopentadienyl compounds of trivalent lanthanoids are dichloride complexes of CpLnCl2(THF) type. Besides these compounds, the ytterbium p-diketonates, lanthanum and cerium iodides (Me5C5)Lnl2 and the lutetium triflate complex CpLu(0S02CF3)2(THF)3 have been obtained (Table 111.14)... 

Cr2Sc3 and CejSea in evacuated silica tubes at 1000°C (4d). Single crystals from a melt of cerium iodide (annealing conditions 800 °C, 30 d). 

Ca2Ba2Cu30 oTl2. Barium calcium copper thallium oxide (Ba2Ca2Cu3Tl20in). [115866-07-41.30 203 Cel2. Cerium iodide (Cel2). [19139-47-0). 30 19... 

Under acidic conditions, perfluoroalkyl iodides (but not bromides) react with sodium hydrogen sulfite and cerium(IV) ions to form the corresponding sulfinates [76] (equation 69). 

Other examples are the use of osmium(VIII) oxide (osmium tetroxide) as catalyst in the titration of solutions of arsenic(III) oxide with cerium(IV) sulphate solution, and the use of molybdate(VI) ions to catalyse the formation of iodine by the reaction of iodide ions with hydrogen peroxide. Certain reactions of various organic compounds are catalysed by several naturally occurring proteins known as enzymes. 

Aravamudan and Venkappayya75 oxidized dimethyl sulphoxide in acetate buffer of pH 4 to 4.5 and with a reaction time of only 1 min. They then added potassium iodide and acid and titrated with thiosulphate the iodine liberated by unused reagent. They reported that cerium(IV) and Cr(VI) were much less effective oxidizing reagents for the sulphoxide. A very similar procedure was used by Rangaswama and Mahadevappa76 to determine dimethyl sulphoxide and numerous other compounds with chloramine B. 

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. 

Sfi.f-Test K.4B In aqueous solution, cerium(lV) ions oxidize iodide ions to solid diatomic iodine and are themselves reduced to cerium(III) ions. Write the net ionic equation for the reaction. 

The course of the reaction has not been elucidated. Probably redox reactions involving cerium(IV) and arsenic(III) are catalyzed by iodide ions and organic iodine compounds with methylene blue acting as a redox indicator. 

The induced reduction of chlorate can be inhibited by iodide, bromide and chloride ions. The effectiveness of these ions is about 400 10 1 in the given order. The order and the magnitude of the effect agree fairly well with the catalytic activity of these ions in the arsenic(III)-cerium(IV) reaction. This inhibition by halides is presumably connected with the opening of a new two-electron route for the arsenic(III)-cerium(IV) reaction. 

Another well-known transformation of carbonyl derivatives is their conversion to pinacols (1,2-diols) via an initial one-electron reduction with highly active metals (such as sodium, magnesium, aluminum, samarium iodide, cerium(III)/ I2, yttrium, low-valent titanium reagents (McMurry coupling), etc.), amines, and electron-rich olefins and aromatics as one-electron donors (D).43 Ketyl formation is rapidly followed by dimerization44 (equation 22). 

Krishnamoorthy and Iyer [105] have reported a method for determining nanogram levels of iodide in saline water samples containing a large excess of interfering chloride ions. The anions are first bound to a strong base anion exchanger, from which the chloride ion is readily eluted. The iodide is then eluted with 2 M ammonium nitrate and the iodide is determined based on its catalytic effect on the reduction of cerium (IV) by arsenic (III). The method is claimed to have an accuracy comparable to that obtained by NAA. 

Organoytterbium chemistry has been developed in the last 20 years, although the development rate is much slower than the other lanthanides like samarium or cerium. Dianionic complexes that are produced from the reaction of ytterbium with diaryl ketones react with various kinds of electrophiles including carbon-heteroatom unsaturated bonds.35 Phenylytterbium iodide, a Grignard-type reagent, is known to have reactivity toward carbon dioxide,36 aldehydes, ketones,37,37 and carboxylic acid derivatives38,3811 to form the corresponding adducts respectively. 

Cerium(III) iodide prepared in situ from an aqueous solution of ceric sulfate first by reduction with sulfur dioxide followed by sodium iodide reduced a-bromoketones to ketones in 82-96% yields [212]. 

K bicarbonate, K chloride, K iodide, K metaphosphate, K perchlorate, K phosphate, K silico-fluoride, K urea oxalate, sodium ammonium sulfate, sulfur, zinc sulfate and Zr oxide It was claimed that methylene urea reduced the flash to a far greater extent than any of the organic compounds used, ft was also stated that cerium salts were much more effective than any other metallic salts investigated (Ref 4)... 

Add a potassium iodide solution to one of cerium(IV) sulphate acidified with sulphuric acid. How can you explain the change in the solution s colour Write the equation of the reaction. What properties do cerium(III) and cerium(IV) salts exhibit ... 

Diphenylphosphine)lithium, 126 Nickel boride, 197 Samarium(II) iodide, 270 to 1,2-disubstituted compounds B-3-Pinanyl-9-borabicyclo-[3.3.1]nonane, 249 Titanium(III) chloride, 302 of phosphorus compounds Lithium aluminum hydride-Cerium(III) chloride, 159 of sulfoxides and sulfones Sodium iodide-Boron trifluoride ether-ate, 282... 

Cerium(IV) ammonium nitrate, 67 Thallium(III) trifluoroacetate, 295 Allylic iodides... 

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