Other Indium Compounds

Other Indium Compounds.—The indium hexathiocyanates, R3[In(NCS)6] (R = NMc4, NEt4, NBu4, or NMe Ph), have been isolated from aqueous solutions. Their i.r. spectra were consistent with In—N co-ordination. 

InR3 (R = alkyl or aryl) may be prepared conveniently by the reaction of diorganomercury species with activated indium metal. The latter is formed by reducing indium salts by alkali metals in hydrocarbon solvents.  

CoIn2 crystallizes with the CuMg2 structure type, space group Fddd. The bond lengths agree well with those calculated for a model based upon hard-sphere contact.  

Augln4(h) crystallizes with the Cu9ln4-type of structure, while Au7ln3 has a hexagonal structure, related to that of y-brass.  

Phase diagrams for the La-In system have been established. The intermetallic compounds La3ln, La2ln, and Laln2 decompose peritectically at 816, 955, and 1153 °C respectively. Lain, La3lns, and Lalnj melt congruently at 1125, 1185, and 1140°C.  

Other Indium Compounds.— Anionic thiocyanato-complexes of In have been prepared—with Ph4As+ or (Ph3PCH2Ph)+ as cation the anion is [In(NCS)5]2 , while with Me4N+, Et3NH+, and BuJN+, [In(NCS) ] is present. Vibrational spectra are consistent with N-bonding of the ligand in each case, in agreement with earlier work on neutral adducts of In thiocyanate.  

Apparent stability constants for In thiocyanato-complexes have been shown to include stability constants of hydroxo- and mixed thiocyanato-hydroxo-indium(m) complexes. The stability constant of the 1 1 thiocyanato-complex is only truly constant at pH ca. 1.  

The formation constants of indium(m)-l,10-phenanthroline and -2,2 -bipyridyl complexes have been determined, as follows (1,10-phen) 

Furukawa, H. Shigemoto, and H. Negita, Bull. Chem. Soc. Japan, 1973, 46, 741. 

The heats of formation of several Hg-In phases have been determined at 81 K, viz. Hggglnii, Hg In, Hggln, Hgin, and Hglng.  

CoIn3 is made from the elements at 400 °C, and is stoicheiometric. It crystallizes in the tetragonal system, and the structure is based on layers of square-triangular nets, related to CoGa3 and Si2U3.575 

Lattice constants have been reported for the hexagonal phases M5In3 (M = Gd, Tb, Dy, Ho, or Y all belong to the W5Si3 structure type) and Y2In (of the Ni2In structure type).576 

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One of the main interests in indium amides has been their potential utility as single-source precursors for indium nitride materials. They also serve as starting materials in the synthesis of various other indium compounds. For instance, amides such as In(NEt2)3 and In[N(SiMe3)t-Bu]3 react with alcohols or thiols to produce indium(III) alkoxides or thiolates, respectively. 

Note The REL also applies to other indium compounds (as In).] OSHA PELf none ... 

A typical multilayer thin film OLED is made up of several active layers sandwiched between a cathode (often Mg/Ag) and an indium-doped tin oxide (ITO) glass anode. The cathode is covered by the electron transport layer which may be A1Q3. An emitting layer, doped with a fluorescent dye (which can be A1Q3 itself or some other coordination compound), is added, followed by the hole transport layer which is typically a-napthylphenylbiphenyl amine. An additional layer, copper phthalocyanine is often inserted between the hole transport layer and the ITO electrode to facilitate hole injection. 

Variable coordination modes in compounds of similar general formula but different compositions (heterogeometrism) has been observed in the case of gallium and indium diisobutyldithiophosphinate pair, M(S2PBu12)3, M = Ga or In the gallium compound is four-coordinate, distorted tetrahedral, whereas the indium compound is six-coordinate, distorted octahedral (Scheme 7).134 Other... 

Salts of InCl2 and Ini2- (see Section 25.2.2.4) serve as the starting point for the synthesis of salts of [In(NCS)2], [In(NCO)2]- and [In(NCS)3]3 by metathesis in ethanol 13 the IR spectrum shows that both ligands are N-bonded in structures which are apparently bridged homopolymers in the solid state. No other pseudohalide compounds of indium(I) have been reported. 

Benzoylation of benzene and other aromatic compounds by benzoyl chloride over H-BEA zeolite modified by indium oxides has been investigated.191 We report in Table 4.2 the time required for half reaction (L/2) f°r a series of aromatic substrates used in the above reaction. The benzoylation reaction rate (via L /2 value) depends strongly on the substituent group present in the aromatic substrate and increases due to the presence of the electron-donating group, depending upon its electron-donating ability. The activity order is as follows benzene toluene < p-xylene < anisole. 

The mobility and resistivity data of single crystalline zinc oxide samples (measured at room temperature) from different authors, which were reported from 1957 to 2005, are displayed in Fig. 2.6 as a function of the carrier concentration (part of these data were taken from [67]). Undoped ZnO crystals exhibit carrier concentrations as low as 1015 cm-3, while indium-doped crystals reach carrier concentrations up to 7 x 1019cm-3. The mobility data show a large scattering between carrier concentrations of 1017 to 5 x 1018cm-3. This is caused by the fact that zinc oxide is a compound semiconductor that is not as well developed as other semiconducting compounds. For instance, only... 

The most widely used preparative method of allylindium(m) or propargylindium(lll) compounds is the oxidative addition of metallic indium or indium(l) halides to allylic or propargyl substrates.4 26 27 Allylic bromides and iodides serve as good allylic sources without any other activation. In the case of allylic chlorides, a proper additive such as lithium iodide is required to promote the oxidative addition. Allylic indium compounds prepared by oxidative addition of metallic indium are considered to exist as the sesquihalide structure (allyl jImXj), which has been... 

Indium-mediated allylation of trialkyl(difluoroacetyl)silane 70 in aqueous media gives homoallylic alcohol 71 exclusively (Scheme 60). Both water and THF are essential for the allylation reaction. It is worth noting that homoallylic alcohol 71 is formed exclusively under these reaction conditions. On the contrary, enol silyl ether 72 is a major product of the fluorinated acylsilanes reaction with other organometallic compounds than indium via a Brook rearrangement and defluorination. Indium-mediated allylsilylation of carbonyl compounds provides a facile route to 2-(hydroxyethyl)allylsilanes. The allene homologs are similarly prepared (Scheme 61).244,244a... 

The carboxylates of indium and thallium are obtained by dissolving the oxides in acid. Acetate and trifluoroacetate salts are used extensively as reagents in organic synthesis. Certain other thallium compounds have been used also. The trifluoroacetate, T1(02CCF3)3, will directly thallate aromatic compounds to give arylthal-lium species, for example, C6H5T1(02CCF3)2 (cf. aromatic mercuration, Section 15-15) and oxidize arenes to biaryls. 

Sulfur complexes of Al, Ga, and In are less common, but the tris(dithiocarba-mates), M(dtc)3, and thiolato anions, Ga(SR)4, are known. The gallium and indium compounds differ structurally from most other tris(dithiocarbamates) in their close approach to a prismatic arrangement of S atoms. 

The growing use of trialkylgallium and -indium compounds in the synthesis of semiconductors has led to the issuance of patented methods for their preparation from metal-magnesium alloys and alkyl halides (68-71). Other such preparations are likely to appear as the need for alkylmetal compounds increases. 

Other organometallic compounds, including aUylic stannanes, allylic samarium, allylic germanium, and allylic indium compounds add to aldi-mines in the same manner. Aryltrialkylstannanes also add the aryl group to Al-tosyl imines using a rhodium catalyst and sonication. Catalytic enantioselective addition reactions are well known, including reactions in an ionic liquid.Allylic... 

The use of InCls for Lewis acid activation of aldehyde substrates leads to rapid transmetalation of the allylic stannane, followed by carbonyl addition reactions of an allyl indium reagent. Premixing of InCb and the allylic stannane in the absence of aldehyde often produces precipitation and poor results. On the other hand, allyl indium reagents have been independently prepared by several procedures, including reductive metalations. Several important reviews describe the methods of preparation and the reactivity of allyl indium compounds. This discussion will be limited to key factors regarding the transmetalation of allylic stannanes in the presence of aldehydes. Stereochemical events leading to the production of anti adducts as major products are illustrated in Scheme 5.2.55. 

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