Of indium metal

AppHcations for electroplated indium coatings include indium bump bonding for shicon semiconductor die attachment to packaging substrates and miscehaneous appHcations where the physical or chemical properties of indium metal are desired as a plated deposit. 

The chemistry of indium metal is the subject of current investigation, especially since the reactions induced by it can be performed in aqueous solution.15 The selective reductions of ethyl 4-nitrobenzoate (entry 1), 2-nitrobenzyl alcohol (entry 2), l-bromo-4-nitrobenzene (entry 3), 4-nitrocinnamyl alcohol (entry 4), 4-nitrobenzonitrile (entry 5), 4-nitrobenzamide (entry 6), 4-nitroanisole (entry 7), and 2-nitrofluorenone (entry 8) with indium metal in the presence of ammonium chloride using aqueous ethanol were performed and the corresponding amines were produced in good yield. These results indicate a useful selectivity in the reduction procedure. For example, ester, nitrile, bromo, amide, benzylic ketone, benzylic alcohol, aromatic ether, and unsaturated bonds remained unaffected during this transformation. Many of the previous methods produce a mixture of compounds. Other metals like zinc, tin, and iron usually require acid-catalysts for the activation process, with resultant problems of waste disposal. 

Although not formally the enamine synthesis, reaction of an enamine with methyl hromoacetate in the presence of indium metal leads to a-aUcylation R2N-CH=CHR R2N-CH(R )CHR. ... 

One notable result is the treatment of 2-hydroxy cyclic ether analog, 2-deoxy-D-ribose with aniline in water catalyzed by InCl3 to afford the novel tricyclic tetrahydroquinoline compounds (Eq. 12.60). The reaction can also be catalyzed by recoverable cation-exchange resin instead of indium chloride.132 By using a stoichiometric amount of indium metal, a domino reaction of nitroarenes with 2,3-dihydrofuran generates the same products. 133... 

The syntheses described below allow such a cycle of operations to be circumvented. As reported previously,2 the electrochemical oxidation of indium metal at room temperature in an organic solvent system yields neutral, anionic, or cationic complexes of indium(III) within 2-3 hours, usually in good crystalline form. These syntheses are significantly quicker and more convenient than the procedures used in this laboratory in previous work. 

FIGURE 2.30 (a) DSC trace for the melting of indium metal (b) integration of the power data to give... 

Indium nitrate can be prepared from InCl3 and N205 158,159 the dissolution of indium metal in cone, nitric acid yields In(N03) xH20 (x = 3, 4, 5),7 which has been used as the source of cationic and anionic complexes.64 Salts of [In(N03)4] have been reported,64160 and Raman studies161,162 have demonstrated the presence of In/NOj complexes in solution the stability constant results have been reviewed.9... 

It is possible to solder most metals directly to glass by use of indium metal (mp 155°C) or an indium alloy such as In 95 % Ag 5 % (mp about 145°C). The heated glass is rubbed with the molten solder to wet the surface and then heated in contact with the metal, which was previously tinned with the solder.10... 

A slot 13 and a ridge is formed at each of the outer edges of an HgCdTe chip 1. Photodiodes 2 are formed between the ridges. The HgCdTe chip is connected to a silicon read-out chip 4 having input regions 2 by the aid of indium metal bumps 7. 

From InCl3, highly reactive low-valent indium(i) species are electrochemically generated and regenerated. These are used for allylation and propargylation of carbonyl compounds (Scheme 3). Of special interest are bisallylations of aromatic and aliphatic esters, since such conversions cannot be achieved by using conventional stoichiometric allylations of esters by means of indium metal or Ini.66... 

Indium-mediated allylation of cyclic and acyclic acid anhydrides gives w-diallyl esters.203,204 Examples are shown in Scheme 48 the allylation of succinic anhydride or phthalic anhydride with allyl bromide in DMF in the presence of indium metal results in the formation of diallylbutenolides or diallylphthalides. In contrast, monoallylated hydroxy esters are formed exclusively with y-substituted allylic halides. 

The direct allylation of aromatic compounds with allylic chlorides is achieved in the presence of a catalytic amount of indium metal. According to the authors, indium is considered to act as a Lewis acid (Equation (101)).399 Trialkylindiums react with acid chlorides to give ketones. When trialkylindiums are treated with air prior to the reaction with acid chlorides, esters are formed (Scheme 121).400 The reaction of cyclopentadienylindium(i) with aldehydes in aqueous media gives mixtures of the isomeric coupling products (Equation (102)).401... 

There are no reports of well-characterized InH2 or its adducts. However, the indium(II) hydride species HInNH2 and HInPH2 have been generated by thermal and photoactivated reactions of indium metal atoms with NH3 or PH3 in solid argon matrices. They have been identified by their IR spectra. 

The use of indium metal in organic or organometallic synthesis is at best very limited. Schumb and Crane69 reported that reaction of several alkyl halides with metallic... 

Naito described the use of indium metal to initiate a radical addition/cyclization cascade in aqueous media. Stirring a mixture of isopropyl iodide, 453, and indium powder in water at 20 °C for 2h produced lactam 454 in 63% yield as a 3 l-mixture of trans- and (Tv-isomers (02OL3835). The reaction of sulfonamide 455 under similar conditions led to the isolation of sultam 456 as a 1 1.5-mixture of isomers in 81% yield. 

Table 3.13 Benzoylation of aromatics with BC in the presence of indium metal...

The procedure essentially mirrors that described in Section A. The reaction mixture consists of indium metal (1.15 g, 10.0 mmol) and diphenyl diselenide (4.73 g, 15.2 mmol) in dry toluene (100 mL). After 3 h of vigorous refluxing, the metal dissolves and the solution becomes light yellow in color. The mixture is filtered hot under dry nitrogen through a sinter to remove... 

The procedure described below for the preparation of indium(I) bromide is extremely simple. Moreover, by appropriate variation of the stoichiometry of the reactants, it can be used for the preparation of indium dibromide. The preparation consists of the reaction of indium metal with mercury(II) bromide at an elevated temperature in a sealed evacuated tube. Mercury (I) bromide can be used in place of the mercury(II) compound. The same method can also be used for the synthesis of the chlorides and iodides of lower-valent indium. ... 

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