Platinum bromides

Aresta (54) and Deutscher (56) have also prepared chelate complexes by reacting the Giignard reagent formed from Triphenyl phosphine displaces the coordinated double bonds to peld the complex... 

The equilibrium of benzoselenazole (4) with gold(III) <91JCS(D)307>, zinc, cadmium, and mercury was studied <81ZAAC(478)233>. The nitrogen of benzoselenazoles reacts with platinum bromide to form the platinum complex (see Section 3.08.12). 

In order to ascertain the surface normal structure of the bromide adlayer and determine the coverage to confirm our structural model, we carried out specular x-ray ray reflectivity measurements. The interpretation of CTR measurements have also been described in several papers and readers are refereed to these papers for details [24, 25, 27]. Briefly sununarizing, the CTR analyses gave the surface coverage of bromide, 0g = 0.43 ML at 0.2 V and Gg = 0.48 ML at 0.7 V. The platinum-bromide layer spacing ( 2.7 A) suggest that bromide is covalently bonded to the platinum (the covalent radii for Pt and Br are 1.30 and 1.14 A, respectively). 

Cesium salts give a deep black precipitate of CsaAuaPtBrjg on reaction with a mixture of gold and platinum bromides (HAuBr4 plus HaPtBr ). The other alkali metals (as chlorides), with the exception of rubidium salts which behave similarly to cesium in concentrations exceeding 2 %, do not react with the reagent. 

Reagent Solution of 0.36 g platinum bromide and 0.60 g gold bromide in 10 ml water... 

This methodology is illustrated by the synthesis of platinum carboxylates through the reaction of platinum bromide complexes with silver carboxylates in dichloromethane, Scheme 5.1 ... 

Bromine has a lower electron affinity and electrode potential than chlorine but is still a very reactive element. It combines violently with alkali metals and reacts spontaneously with phosphorus, arsenic and antimony. When heated it reacts with many other elements, including gold, but it does not attack platinum, and silver forms a protective film of silver bromide. Because of the strong oxidising properties, bromine, like fluorine and chlorine, tends to form compounds with the electropositive element in a high oxidation state. 

PtCl2, and platiaum tetrachloride [37773-49-2]. Platiaum dichloride exists in an a- and P-form, the latter containing a Pt core and edge-bridging chlorides. Platinum trichloride [25909-39-1], PtCl, contains Pt(II) and Pt(IV) centers. Other haHdes include two bromides, PtBr2 [13455-12-4] and PtBr ... 

Reaction with Hydrogen and Metals. Bromine combines directiy with hydrogen at elevated temperatures and this is the basis for the commercial production of hydrogen bromide [10036-10-6]. Heated charcoal and finely divided platinum metals are catalysts for the reaction (17). 

Bromine and bromides can be detected quaUtatively by a number of methods. In higher concentrations bromine forms colored solutions in solvents such as carbon tetrachloride [56-23-5] and carbon disulfide [75-15-0]. Bromine reacts with yeUow disodium fluorescein [518-47-8] to form red disodium tetrabromofluorescein (eosin) [548-26-5] C2QH Br4Na20. As Httle as 0.3 p.g of bromide can be detected and chlorides do not interfere (56). Bromine reacts with platinum sulfate [7446-29-9] Pt(S0 2> solution to form red to brown crystals of potassium hexabromoplatinate [16920-93-7] K PtBr ( )-... 

Other Metals. Ruthenium, the least expensive of the platinum group, is the second best electrical conductor, has the hardest deposit, and has a high melting point. A general purpose bath uses 5.3 g/L of mthenium as the sulfamate salt with 8 g/L sulfamic acid, and is operated at 25—60°C with a pH of 1—2. Osmium has been plated from acid chloride solutions (130) and iridium from bromide solutions, but there are no known appHcations for these baths. 

The eleetroehemieal oxidation of solution eontaining iodide- and bromide-ions in HCIO is earned out. Work and auxiliary eleetrodes are platinum. At this potential sueh reaetions are running ... 

The reaction product (1-carbethoxymethyM-carbomethoxy-pyridinium bromide) was obtained in crystalline form. (It formed prisms melting at 166°-169°C after recrystallization from a mixture of isopropanol and acetone.) It was not necessary to isolate it. For the following reduction step, the reaction mixture was brought into solution by the addition of about 1 liter of warm ethyl alcohol. It was then hydrogenated at about 30 atm pressure in the presence of 2 g of platinum oxide. The temperature rose during this reaction to about 40°C. 

Iridium has been deposited from chloride-sulphamate and from bromide electrolytes , but coating characteristics have not been fully evaluated. The bromide electrolytes were further developed by Tyrrell for the deposition of a range of binary and some ternary alloys of the platinum metals, but, other than the platinum-iridium system, no commercial exploitation of these processes has yet been made. 

Follow die directions for Question 7 for a salt bridge cell in which die anode is a platinum rod immersed in an aqueous solution of sodium iodide containing solid iodine crystals. The cathode is another platinum rod immersed in an aqueous solution of sodium bromide with bromine liquid. 

Discussion. Bromine may be electro-generated with 100 per cent current efficiency by the oxidation of bromide ion at a platinum anode. Bromination of oxine proceeds according to the equation ... 

Note. The above techniques are generally applicable to many other acids, both strong and weak. The only limitation is that the anion must not be reducible at the platinum cathode and must not react in any way with the silver anode or with silver bromide (e.g. by complexation). 

Dilute solutions of antimony(III) and arsenic(III) (ca 0.0005M) may be titrated with standard 0.002 M potassium bromate in a supporting electrolyte of 1M hydrochloric acid containing 0.05 M potassium bromide. The two electrodes are a rotating platinum micro-electrode and an S.C.E. the former is polarised to +0.2 volt. A reversed L-type of titration graph is obtained. 

When 1-methyl-, 1,2- and 1,3-dimethyl-indoles were oxidized on a platinum electrode in methanolic ammonium bromide solution, in addition to the oxidation products, products of nuclear bromination at the 3-and 5-positions were observed. 1,2- Dimethylindole (20) gave 3-bromo-1,2-dimethylindole (81CCC3278) [bromine in chloroform gave the same product (85CHE786)]. In acidic conditions the amidinium cation formed from 20 was brominated in the 5-position (Scheme 14). Acylated 2-aminoindoles reacted similarly in neutral media to give 3-bromo derivatives and when protonated to give 5-bromo products. Bromine in chloroform transformed l-methyl-2-dimethylaminoindole (21) into the 3-bromo derivative (85CHE782) (Scheme 15). 

Unlike ruthenium (and other platinum metals) osmium forms chlorides and bromides in a range of oxidation states [11,12]. 

Tin, nitratodiphenyltris(dimethy) sulfoxide)-structure, 1,77 Tin, nitratotris(triphenyltin)-structure, 1, 47 Tin,tetrakis(acetato)-stereochemistry, 1,94 Tin, tetrakis(diethyldithiocarbamato)-angular parameters, 1, 57 Tin, tetrakis(ethyldithiocarbamato)-angular parameters, 1, 57 Tin, tetranitrato-stereochemistry, 1, 94 Tin, tri-n-butylmethoxy-, 3, 208 Tin alkoxides physical properties, 2, 346 Tin bromide, 3, 194 Tin bromide hydrate, 3,195 Tin carboxylates, 3, 222 mixed valence, 3, 222 Tin chloride, 3, 194 hydroformylation platinum complexes, 6, 263 Tin chloride dihydrate, 3,195 Tin complexes, 3, 183-223 acetyl ace tone... 

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