Indium , reaction

Figure Bl.25.9(a) shows the positive SIMS spectrum of a silica-supported zirconium oxide catalyst precursor, freshly prepared by a condensation reaction between zirconium ethoxide and the hydroxyl groups of the support [17]. Note the simultaneous occurrence of single ions (Ff, Si, Zr and molecular ions (SiO, SiOFf, ZrO, ZrOFf, ZrtK. Also, the isotope pattern of zirconium is clearly visible. Isotopes are important in the identification of peaks, because all peak intensity ratios must agree with the natural abundance. In addition to the peaks expected from zirconia on silica mounted on an indium foil, the spectrum in figure Bl. 25.9(a)...

The use of indium in acpieous solution has been reported by Li and co-workers as a new tool in org nometallic chemistry. Recently Loh reported catalysis of the Mukaiyama-aldol reaction by indium trichloride in aqueous solution". Fie attributed the beneficial effect of water to a eg tion phenomena in connection with the high internal pressure of this solvenf This woric has been severely criticised by... 

In summary, the groups of Espenson and Loh observe catalysis of Diels-Alder reactions involving monodentate reactants by Lewis acids in water. If their observations reflect Lewis-acid catalysis, involvirg coordination and concomitant activation of the dienophile, we would conclude that Lewis-acid catalysis in water need not suffer from a limitation to chelating reactants. This conclusion contradicts our observations which have invariably stressed the importance of a chelating potential of the dienophile. Hence it was decided to investigate the effect of indium trichloride and methylrhenium trioxide under homogeneous conditions. 

Sulfates. Indium metal and its oxides dissolve in warm sulfuric acid to give a solution of the trisulfate [13464-82-9], In2(S0 2- It is a white, crystalline, deUquescent soHd, readily soluble in water that forms double salts with alkaLi sulfates and some organic substituted ammonium bases. Concentration of the acidified trisulfate solution produces indium acid sulfate crystal [57344-73-7], In(HS0 2> other reaction conditions give basic sulfates. 

Metallic Antimonides. Numerous binary compounds of antimony with metallic elements are known. The most important of these are indium antimonide [1312-41 -0] InSb, gallium antimonide [12064-03-8] GaSb, and aluminum antimonide [25152-52-7] AlSb, which find extensive use as semiconductors. The alkali metal antimonides, such as lithium antimonide [12057-30-6] and sodium antimonide [12058-86-5] do not consist of simple ions. Rather, there is appreciable covalent bonding between the alkali metal and the Sb as well as between pairs of Na atoms. These compounds are useful for the preparation of organoantimony compounds, such as trimethylstibine [594-10-5] (CH2)2Sb, by reaction with an organohalogen compound. 

The electrolytic cells shown ia Figures 2—7 represent both monopolar and bipolar types. The Chemetics chlorate cell (Fig. 2) contains bipolar anode/cathode assembhes. The cathodes are Stahrmet, a registered trademark of Chemetics International Co., and the anodes are titanium [7440-32-6] Ti, coated either with mthenium dioxide [12036-10-17, RUO2, or platinum [7440-06-4] Pt—indium [7439-88-5] Ir (see Metal anodes). Anodes and cathodes are joined to carrier plates of explosion-bonded titanium and Stahrmet, respectively. Several individual cells electrically connected in series are associated with one reaction vessel. 

Rapp (1961) has confirmed this equation in a study of the oxidation in air of Ag-In alloys at 550°C. The reaction proceeds with tire internal formation of In203 particles over a range of indium concenuations, but at a critical mole fraction of indium in the alloy, external oxidation occurs with the growdr of a layer of In203 covering the alloy. The n airsitioir from internal to external oxidation was found by Rapp to occur at the mole fraction of indium cone-sponding to... 

Indium clusters have also recently been characterized, notably in intermetallic compounds. Thus, the Zintl phase, Rbzinj, (prepared by direct reaction between the two metals at I530°C) has layers of octahedral closo-lnf, clusters joined into sheets through exo bonds at four coplanar vertices. These four In atoms are therefore each bonded to five neighbouring In atoms at the comers of a square-based pyramid, whereas the remaining two (Irans) In atoms in the Ine cluster... 

Recently, solvent-free Skraup/Doebner-von Miller reactions have been developed under microwave radiation. For example, aniline 34 and enone 35 are reacted in the presence of silica gel impregnated with indium trichloride to give the corresponding quinoline 36 in good yield. It was subsequently shown that both electron-rich and electron-poor anilines undergo cyclization in a similar fashion. 

Reactions of heterocycles in aqueous media with participation of indium compounds as reagents or catalysts 99T11149. 

As shovm in Eq 6 59, Rapoport has prepared sinefungin, nucleoside andbiodcs, via nitro-aldol reaction, dehydradon, and reducdon v/iihZn in acetic acid fi-Niiro styrenes are selecdvity reduced to the corresponding oximes by indium metal in aqueous methanol under neutral conthdons ... 

Scheme 5.1-43 Three-component reaction of benzaldehyde, aniline, and diethyl phosphonate in ionic liquids, catalyzed by lanthanide triflates and indium(lll) chloride.

More than 1500 radioactive isotopes have been prepared in the laboratory. The number of such isotopes per element ranges from 1 (hydrogen and boron) to 34 (indium). They are all prepared by bombardment reactions in which a stable nucleus is converted to one... 

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,... 

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. 

Imino Diels-Alder reactions catalyzed by indium trichloride (InCIs). Facile synthesis of quinoline and phenanthridinone derivatives [106]... 

Indium trichloride [30] and methylrhenium trioxide [31] catalyze the aqueous Diels-Alder reaction of acrolein and acrylates with cyclic and open-chain dienes. Some examples of the cycloaddition of methyl vinyl ketone with 1,3-cyclohexadiene are reported in Scheme 6.18. MeReOs does not give satisfactory yields for acroleins and methyl vinyl ketones with substituents at the jS-position and favors the self-Diels-Alder reaction of diene. 

Babu G., Perumal P. T. Synthetic Applications of Indium Trichloride Catalyzed Reactions Aldrichimica Acta 2000 33 16-22... 

Scheme 37 shows a reaction sequence leading to a mono(amidinato) indium bia(arylimido) complex. Subsequent treatment of the latter with Ti(NMe2)4 resulted in formation of the heterobimetallic In/Ti complex [But(NPr )2]In /t-NCgH3Pri-2,6 2Ti(NMe2)2 (cf. Sections 111.B.2 and V.A.l)." ... 

In contrast, reactions of trimethylindium with free amidines led to formation of dinuclear amidinate-bridged indium complexes. These reactions are illustrated in Scheme 38. ... 

---