Platinum, hydration

Ammonia forms a great variety of addition or coordination compounds (qv), also called ammoniates, ia analogy with hydrates. Thus CaCl2 bNH and CuSO TNH are comparable to CaCl2 6H20 and CuSO 4H20, respectively, and, when regarded as coordination compounds, are called ammines and written as complexes, eg, [Cu(NH2)4]S04. The solubiHty ia water of such compounds is often quite different from the solubiHty of the parent salts. For example, silver chloride, AgQ., is almost iasoluble ia water, whereas [Ag(NH2)2]Cl is readily soluble. Thus silver chloride dissolves ia aqueous ammonia. Similar reactions take place with other water iasoluble silver and copper salts. Many ammines can be obtained ia a crystalline form, particularly those of cobalt, chromium, and platinum. 

Evaporation of solutions of platinum in aqua regia gives yellow crystals of the hydrates tra s-[PtCl4(H20)2].3H20 and/uc-[PtCl3(H20)3]Cl iH20 [25]. 

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... 

Schemes 6-18 A plausible mechanism of hydration of acetonitrile catalyzed by unhindered hydridobis(phosphine)platinum(II) complexes...

Some Pt complexes bearing electron-donating phosphines can also catalyze the hydration of the C=C double bond of acrylonitrile or crotonitrile and yielded P-hy-droxypropionitrile or P-hydroxybutyronitrile respectively besides the corresponding amide (Eq. 6.38) [22, 75], Among the platinum phosphine complexes examined, [Pt(PEt3)3] (26a), carrying less bulky ligands, was the most effective for the hydration of the olefmic bond. The present catalyst system was ineffective for hydration of other olefins, however. 

Efficient anti-Markonikov addition of water to terminal olefins producing primary alcohols would be one of the most desirable catalytic processes (Eq. 6.45). As one example of such a reaction, Jensen and Trogler reported the anti-Markonikov hydration of terminal olefins catalyzed by a platinum(II) trimethylphosphine complex producing primary alcohols [83]. The report, however, was claimed to be of doubtful reproducibility [84]. 

More recently, Atwood et al. developed a platinum complex of a water-soluble, bidentate phosphine ligand, cA-(TPPTS)2PtCl2 [TPPTS = tris(sodium m -benzenesuI onatc)phosphi nc, as an effective hydration... 

C23H32N10O16P2Pt2--0.4 CioHnN408P2- 2.4 Na+-13.8 HzO Sodium (trimethylenediamine)bis(inosine 5 -phosphato)platinum(II) inosine 5 -phosphate, hydrate (INOSPU)347... 

C20H28N 10O16P2Pt2- 0.88 hydrate Sodium diammine-platinum-(inosine 5 -phosphate)-inosine SINPPT 34 375... 

Rate and equilibrium constant data, including substituent and isotope effects, for the reaction of [Pt(bpy)2]2+ with hydroxide, are all consistent with, and interpreted in terms of, reversible addition of the hydroxide to the coordinated 2,2 -bipyridyl (397). Equilibrium constants for addition of hydroxide to a series of platinum(II)-diimine cations [Pt(diimine)2]2+, the diimines being 2,2 -bipyridyl, 2,2 -bipyrazine, 3,3 -bipyridazine, and 2,2 -bipyrimidine, suggest that hydroxide adds at the 6 position of the coordinated ligand (398). Support for this covalent hydration mechanism for hydroxide attack at coordinated diimines comes from crystal structure determinations of binuclear mixed valence copper(I)/copper(II) complexes of 2-hydroxylated 1,10-phenanthroline and 2,2 -bipyridyl (399). 

A direct evidence of the way of tetrahedral anion adsorption at three-fold sites and the degree of hydratation is not available at present. However, a strong indication of such adsorption of sulphates is found in voltammetry on gold (14) and in our data for platinum surfaces (12). A pronounced difference between the sulphate and perchlorate adsorption effects is... 

The analogous hydroxylation of alkynes to produce ketones is enhanced by the co-catalytic effect of Aliquat and platinum(IV) chloride-carbon monoxide [3] it is assumed that HPtCI(CO) is the active hydration species. C-S and C-Br bonds are cleaved under the reaction conditions. 

Fig. 8-40. Transfer currents of redox electrons observed on a platinum electrodes covered with a thin platinum oxide film of PtO in acidic solutions as a function of film thickness hydrated redox particles Fe /Fe at 0.98 V he in acidic solution at pH 0 hydrated redox particles Ce /Ce at 1.0 in acidic solution at pH 3. [From Schultze, 1978 Schultze-Vetter, 1973.]...

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