Palladium indium

Grigg and co-workers described a novel three-component indium-palladium-mediated allylation reaction [67]. As exemplified by Eq. 14.16, 3,3-disubstituted oxi-ndole derivative 133 was obtained smoothly from phenyl iodide, the easily available isatin imine 132 and 1,2-propadiene (131). Excellent levels of diastereoselectivity were obtained in this cascade reaction employing imines derived from enantiopure sulfmamides. 

In research at the Institute of Radiochemistry, Karlsruhe, West Germany, during the early 1970s, investigators prepared alloys of neptunium with indium, palladium, platinum, and rhodium. These alloys were prepared by hydrogen reduction of the neptunium oxide in (he presence of finely divided noble metals. The reaction is called a coupled reaction because the reduction of the metal oxide can be done only m the presence of noble metals. The hydrogen must be extremely pure, with an oxygen content of less than 10 25 torr. 

The limits are very low at fractions of parts per billion. A similar table exists for mercury emission limits (EC directive 84/156/EEC) but with even stricter emission limits. In the UK cadmium legislation has recently become stricter, in line with the EC initiative. December 1993 saw the publication, in the UK, of the Department of the Environment Process Guidance Notes (IPR 4/22) related to the manufacture of zinc, lead, antimony, arsenic, beryllium, gallium, indium, palladium, platinum, selenium, tellurium, thallium and their compounds. The publication tabulates potential sources of metal emission and places a large emphasis on effective and efficient waste minimisation techniques. The document sets the scene for stricter legislation on metal emissions in the UK. 

Alloys suitable for castings that ate to be bonded to porcelain must have expansion coefficients matching those of porcelain as well as soHdus temperatures above that at which the ceramic is fired. These ate composed of gold and palladium and small quantities of other constituents silver, calcium, iron, indium, tin, iridium, rhenium, and rhodium. The readily oxidi2able components increase the bond strength with the porcelain by chemical interaction of the oxidi2ed species with the oxide system of the enamel (see Dental materials). 

Some metals used as metallic coatings are considered nontoxic, such as aluminum, magnesium, iron, tin, indium, molybdenum, tungsten, titanium, tantalum, niobium, bismuth, and the precious metals such as gold, platinum, rhodium, and palladium. However, some of the most important poUutants are metallic contaminants of these metals. Metals that can be bioconcentrated to harmful levels, especially in predators at the top of the food chain, such as mercury, cadmium, and lead are especially problematic. Other metals such as silver, copper, nickel, zinc, and chromium in the hexavalent oxidation state are highly toxic to aquatic Hfe (37,57—60). 

The platinum-group metals (PGMs), which consist of six elements in Groups 8— 10 (VIII) of the Periodic Table, are often found collectively in nature. They are mthenium, Ru rhodium, Rh and palladium, Pd, atomic numbers 44 to 46, and osmium. Os indium, Ir and platinum, Pt, atomic numbers 76 to 78. Corresponding members of each triad have similar properties, eg, palladium and platinum are both ductile metals and form active catalysts. Rhodium and iridium are both characterized by resistance to oxidation and chemical attack (see Platinum-GROUP metals, compounds). 

Hardness of the aimealed metals covers a wide range. Rhodium (up to 40%), iridium (up to 30%), and mthenium (up to 10%) are often used to harden platinum and palladium whose intrinsic hardness and tensile strength are too low for many intended appHcations. Many of the properties of rhodium and indium. Group 9 metals, are intermediate between those of Group 8 and Group 10. The mechanical and many other properties of the PGMs depend on the physical form, history, and purity of a particular metal sample. For example, electrodeposited platinum is much harder than wrought metal. 

Aqueous Electrodeposition. The theory of electro deposition is well known (see Electroplating). Of the numerous metals used in electro deposition, only 10 have been reduced to large-scale commercial practice. The most commonly plated metals are chromium, nickel, copper, zinc, rhodium, silver, cadmium, tin, and gold, followed by the less frequendy plated metals iron, cesium, platinum, and palladium, and the infrequendy plated metals indium, mthenium, and rhenium. Of these, only platinum, rhodium, iddium, and rhenium are refractory. 

The first catalytic study of Reaction 1 was published in 1902 by Sabatier and Senderens (1) who reported that nickel was an excellent catalyst. Since that time, the active catalysts were identified as the transition elements with unfilled 3d, 4d, and 5d orbitals iron, cobalt, nickel, ruthenium, rhenium, palladium, osmium, indium, and platinum, as well as some elements that can assume these configurations (e.g., silver). These are discussed later. For practical operation of this process,... 

Rubidium Strontium Yttrium Zircomum Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium indium Tin Antimony IJtunum Iodine Xenon... 

Alkynes react with indium reagents such as (allyl)3ln2l3 to form dienes (allyl substituted alkenes from the alkyne). Allyltin reagents add to alkynes in a similar manner in the presence of ZrCU Alkylzinc reagents add to alkynes to give substituted alkenes in the presence of a palladium catalyst. ... 

Palladium catalyzes allylation of carbonyl compounds with various ally lie compounds using In-InCl3 in aqueous media (Eq. 8.66).158 Various allylic compounds can be effectively applied via the formation of TT-allylpalladium(II) intermediates and their transmetalation with indium in the presence of indium trichloride in aqueous media. 

Reaction with Propargyl Halides. The indium-mediated coupling of propargyl bromide with a variety of imines and imine oxides afforded homo-propargylamine derivatives in aqueous media under mild conditions.78 Propargylation of glyoxylic oxime ether in the presence of a catalytic amount of palladium(O) complex and indium(I) iodide in aqueous media was also studied (Eq.11.47).79... 

Just a few years after the discovery of the deposition and electroactivity of Prussian blue, other metal hexacyanoferrates were deposited on various electrode surfaces. However, except for ruthenium and osmium, the electroplating of the metal or its anodizing was required for the deposition of nickel [14], copper [15,16], and silver [9] hexacyanoferrates. Later studies have shown the possibilities of the synthesis of nickel, cobalt, indium hexacyanoferrates similar to the deposition of Prussian blue [17-19], as well as palladium [20-22], zinc [23, 24], lanthanum [25-27], vanadium [28], silver [29], and thallium [30] hexacyanoferrates. 

Cleghorn LAT, Cooper IR, Grigg R, MacLachlan WS, Sridharan V (2003b) Additive effects in palladium-indium mediated Barbier type allylations. Tetrahedron Lett 44 7969-7973... 

Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon... 

Palladium catalyzed cross-coupling reactions of 1-substituted glycals have not only been limited to tributylstannyl derivatives. In fact, the versatility of this approach is significantly enhanced by the fact that C-l zinc-, indium-, or iodine-substituted glycals (easily accesible from glycals, see Scheme 7)... 

Antimony, arsenic, bismuth, cadmium, calcium, cesium, chromium, cobalt, copper, gold, indium, iridium, iron, lead, lithium, magnesium, manganese, mercury, nickel, palladium, platinum, potassium, rhodium, rubidium, ruthenium, selenium, silver, sodium, tellurium, thallium, zinc... 

Conventionally, organometallic chemistry and transition-metal catalysis are carried out under an inert gas atmosphere and the exclusion of moisture has been essential. In contrast, the catalytic actions of transition metals under ambient conditions of air and water have played a key role in various enzymatic reactions, which is in sharp contrast to most transition-metal-catalyzed reactions commonly used in the laboratory. Quasi-nature catalysis has now been developed using late transition metals in air and water, for instance copper-, palladium- and rhodium-catalyzed C-C bond formation, and ruthenium-catalyzed olefin isomerization, metathesis and C-H activation. Even a Grignard-type reaction could be realized in water using a bimetallic ruthenium-indium catalytic system [67]. 

The possible preparation of InAs by crystallization from the melt depends also on the liquidus shape (especially in the In-rich region). A summary of previous liquidus measurements was reported by De Winter and Pollack (1986) who employed a source dissolution method based on the equilibration, at a fixed temperature, of a known quantity of high-purity indium with single crystals of InAs, the weight loss of which was determined. The experiments were carried out under a flux of hydrogen purified via permeation through palladium. 

Gold, 0110 Hafnium, 4599 Indium, 4640 Iridium, 4643 Lanthanum, 4677 Lead, 4882 Lithium, 4680 Magnesium, 4690 Manganese, 4700 Mercury, 4600 Molybdenum, 4712 Neodymium, 4819 Nickel, 4820 Niobium, 4817 Osmium, 4873 Palladium, 4885 Platinum, 4887 Plutonium, 4888 Potassium, 4645 Praseodymium, 4886 Rhenium, 4890 Rhodium, 4892 Rubidium, 4889 Ruthenium, 4894 Samarium, 4911... 

In the commercial flow sheets, these elements are left in the aqueous raffinate after platinum and palladium extraction. Indium can be extracted in the -l-IV oxidation state by amines (see Fig. 11.11), or TBP (see Figs. 11.10 and 11.12). However, although the separation from rhodium is easy, the recovery of iridium may not be quantitative because of the presence of nonextractable iridium halocomplexes in the feed solution. Dhara [37] has proposed coextraction of iridium, platinum, and palladium by a tertiary amine and the selective recovery of the iridium by reduction to Ir(III). Iridium can also be separated from rhodium by substituted amides [S(Ir/ Rh) 5 X 10 ). 

Schroeder HA, Mitchener M Scandium, chromium (VI) gallium, yttrium, rhodium, palladium, indium in mice Effects on growth and life span. J Nutr 101 1431-1438, 1971... 

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