Bromine compounds and complexes

Vin.3 Bromine compounds and complexes VIII.3.1 Solid and gaseous thorium bromides VIIL3.1.1 ThBr(g), ThBr2(g), ThBr3(g)... 

Acetylene is condensed with carbonyl compounds to give a wide variety of products, some of which are the substrates for the preparation of families of derivatives. The most commercially significant reaction is the condensation of acetylene with formaldehyde. The reaction does not proceed well with base catalysis which works well with other carbonyl compounds and it was discovered by Reppe (33) that acetylene under pressure (304 kPa (3 atm), or above) reacts smoothly with formaldehyde at 100°C in the presence of a copper acetyUde complex catalyst. The reaction can be controlled to give either propargyl alcohol or butynediol (see Acetylene-DERIVED chemicals). 2-Butyne-l,4-diol, its hydroxyethyl ethers, and propargyl alcohol are used as corrosion inhibitors. 2,3-Dibromo-2-butene-l,4-diol is used as a flame retardant in polyurethane and other polymer systems (see Bromine compounds Elame retardants). 

There are a number of complex chlorides of three general types M(MnCl2), M2(MnCl, and M4(MnClg). M is monovalent in each case. Fluorine forms only 9M(MnF.) and the only complex bromine compound reported is Ca(MnBt 4H2O. There are no iodide complexes. The anhydrous salt, MnCl2, forms cubic pink crystals, and three well-defined hydrates exist. Aqueous solubiUties of the tetrahydrate and dihydrate ate given in Table 7. 

The Ullman reaction has long been known as a method for the synthesis of aromatic ethers by the reaction of a phenol with an aromatic halide in the presence of a copper compound as a catalyst. It is a variation on the nucleophilic substitution reaction since a phenolic salt reacts with the halide. Nonactivated aromatic halides can be used in the synthesis of poly(arylene edier)s, dius providing a way of obtaining structures not available by the conventional nucleophilic route. The ease of halogen displacement was found to be the reverse of that observed for activated nucleophilic substitution reaction, that is, I > Br > Cl F. The polymerizations are conducted in benzophenone with a cuprous chloride-pyridine complex as a catalyst. Bromine compounds are the favored reactants.53,124 127 Poly(arylene ether)s have been prepared by Ullman coupling of bisphenols and... 

The main difference between the structures of compound (IV) and compounds (I), (II), and (III) is that in compound (IV) half of the bridging and terminal bromine atoms, and all the axial bromine atoms, are substituted by iodine atoms, with partial substitution being statistical [75]. Thus, according to the X-ray diffraction data, the effective Tc-Tc distances are intermediate between analogous distances in bromide and iodide complexes of technetium(IV) (Table 1) [104,105]. We observed that the substitution of I for Br has almost no effect on the Tc-Tc distances. 

Russian scientists (Avrorin et al., 1981, 1985) have reported that reactions of complex mixtures of radon, xenon, metal fluorides, bromine pentafluoride, and fluorine yield a higher fluoride of radon which hydrolyzes to form RnO. However, efforts to confirm these findings have been unsuccessful. In similar experiments which have been carried out at Argonne National Laboratory (Stein, 1984), it has been found that radon in the hydrolysate is merely trapped in undissolved solids centrifugation removes the radon from the liquid phase completely. This is in marked contrast to the behavior of a solution of XeO, which can be filtered or centrifuged without loss of the xenon compound. Hence there is no reliable evidence at present for the existence of a higher oxidation state of radon or for radon compounds or ions in aqueous solutions. Earlier reports of the preparation of oxidized radon species in aqueous solutions (Haseltine and Moser, 1967 Haseltine, 1967) have also been shown to be erroneous (Flohr and Appelman, 1968 Gusev and Kirin, 1971). 

The behaviour of the phosphine complex PtBr2(ap)2 towards bromination is in marked contrast to that of PtBr2(oA)2 (the related arsine complex). Whilst the arsine complex gives platinum(IV) species on reaction with one equivalent of bromine, the phosphine complex gives the chelate compound PtBr2 (ap), and, presumably, CH2=CH CH2 ... 

The resolution was carried out by means of d-bromo-camphor-sulphonie acid. The salts of the bromo-series are more easily resolved on account of the great difference between the isomeric d-bromo-camphor sulphonates. In both series the d-bromo-eamphor sulphonate of the d-isomer is more sparingly soluble. These active compounds are very stable, and aqueous solutions of the bromides of the bromo-ammine series may be kept for a considerable time at ordinary temperatures, and even on heating to boiling racemisation does not occur. If the bromine in the complex be removed by means of silver nitrate activity... 

Dioximes form bis complexes (35) where the ligand normally chelates through the nitrogen atoms.251-253 Detailed studies have been made of the partially oxidized compounds obtained from reaction of bis(diphenylglyoximato)- and bis(benzoquinone dioximato)-palladium with iodine254,255 and bromine.256 These complexes contain polyhalide anions and possess the high anisotropic electrical conductivity associated with many complexes which crystallize as stacked molecular units.257... 

The usual reaction between olefins and bromine or chlorine is illustrated in Scheme 11. Final products are di-brominated compounds 29. Theoretical studies76 agree with Scheme 11. Both Schemes 10 and 11 involve a quickly established equilibrium of formation of a CT complex between olefin and bromine. 

Segraves EN, Shah RR, Segraves NL, Johnson TA, Whitman S, Sui JK, Kenyon VA, Cichewicz RH, Crews P, Holman TR (2004) Probing the Activity Differences of Simple and Complex Brominated Aryl Compounds Against 15-Soybean, 15-Human, and 12-Human Lipoxygenase. J Med Chem 47 4060... 

Reaction of 3-hydroxy-oxonene 103 with the complex of bromine and l,2-bis(diphenylphosphino)ethane resulted in an expected mixture of brominated compounds 105 and 106, along with single stereoisomer of oxocene 107, probably due to the formation of the bridged oxonium cation and its two different directions of the reaction with bromide anion (Scheme 17, Section 14.10.5.5.3) <1995TL8263>. 

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