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Single crystals (SCs) of the compounds Eu3Ag2In9 and EuCu2Ge2 were synthesized through the reactions run in liquid indium. Eu3Ag2In9 crystallizes in the La3Al11 structure type [orthorhombic space group (SG) Immm] with the lattice parameters: a = 4.8370(1) A, b = 10.6078(3) A, and c = 13.9195(4) A. EuCu2Ge2 crystallizes in the tetragonal ThCr2Si2 structure type (SG I4/mmm) with the lattice parameters: a = b = 4.2218(1) A, and c = 10.3394(5) A. The crystal structure of Eu3Ag2In9 is comprised of edge-shared hexagonal rings consisting of indium. The one-dimensional chains of In6 rings are shared through the edges, which are further interconnected with other six-membered rings forming a three-dimensional (3D) stable crystal structure along the bc plane. The crystal structure of EuCu2Ge2 can be explained as the complex [CuGe](2+δ)– polyanionic network embedded with Eu ions. These polyanionic networks present in the crystal structure of EuCu2Ge2 are shared through the edges of the 011 plane containing Cu and Ge ...

Polycrystalline In19B34O74(OH)11 is prepared by hot pressing of stoichiometric amounts of In2O3 and H3BO3 (Au foil in multianvil press, 13 GPa within 12 h, 1150 °C, 6 min; cooling to 850 °C within 40 min; decompression within 21 h).

ConspectusStereoselective indium-mediated organic reactions have enjoyed tremendous growth in the last 25 years. This is in part due to the insensitivity of allylindium to moisture, affording facile and practical reaction conditions coupled with outstanding functional group tolerance and minimal side reactions. Despite the plethora of articles about allylindium, there is much yet to be discovered and exploited for efficient and sustainable synthesis.In this Account, we describe indium-mediated synthetic methods for the preparation of chiral amines with the aim to present a balance of practical method development, novel asymmetric chemistry, and mechanistic understanding that impact multiple chemical and materials science disciplines. In 2005, we demonstrated the indium-mediated allylation of chiral hydrazones with complete diastereoselectivity (>99:1) and quantitative yields. Further, we revealed the first example of enantioselective indium-mediated allylation of hydrazones using catalytic (R)-3,3′-bis(tr...

The indium-mediated Blaise-type reaction of bromomalonates with nitriles and isocyanates is described. The choice of the solvent is crucial for the successful reaction; the dependency on dichloromethane proved to be nonplussed. The reaction with nitriles led to the corresponding β-enamino diesters in moderate to good yields. The conversion with isocyanates generated carbamoyl malonates in good to excellent yields. Both reactions tolerated various functional groups regarding the electronic nature. Also, steric hindrance in the starting materials, as caused by mesityl isocyanate or diisopropyphenyl isocyanate, was well tolerated. In addition, a sequential three-component one-pot reaction sequence is described for the formation of 2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylates enabling future investigations in this field.

A series of dihydrofurans (III), (V), and (XIII) is readily prepared by an indium-catalyzed reaction of ketones with alkenes in the presence of Ag2O.

An InI3–TMDS (1,1,3,3-tetramethyldisiloxane) reducing system efficiently catalyzed a sequential three-component coupling of aliphatic carboxylic acids, aromatic carboxylic acids, and t-butyl mercaptan (t-butylthiol), to produce unsymmetrical dialkyl sulfides. With this reducing system, t-butyl mercaptan became a new source of sulfidation via an alkyl t-butyl sulfide that functioned as the reaction intermediate.

A simple and efficient protocol has been developed for the synthesis of 5-substituted 1H-tetrazole derivatives in good to excellent yields from various oximes and sodium azide by using indium(III) chloride as a Lewis acid catalyst. The present method has significant advantages, such as an inexpensive catalyst, low catalyst loading, mild reaction conditions, and simple experimental procedures.

Diverse and functionalized 2-hydroxybenzophenone derivatives were synthesized efficiently in good to excellent yield via the highly regioselective indium(III)-catalyzed [2+2+2] benzannulation of 3-formylchromones with β-enamino esters or β-enamino ketones. This benzannulation reaction proceeds via a domino Michael/retro-Michael/6π-electrocyclization/deformylation reaction. In addition, 2-hydroxybenzophenones were also prepared by the indium(III)-catalyzed [4+2] benzannulation reaction between 3-substituted chromen-4-ones and β-enamino esters or β-enamino ketones. Furthermore, the effects of substituents and π conjugation on the characteristics of the UV-Vis spectrum of synthesized 2-hydroxybenzophenones were examined. Compound 10s exhibited higher sun protection activity than oxybenzone which is used in most popular sunscreens.

Despite six decades use of aluminum as a galvanic (sacrificial) anode, there remains a need for a better understanding of the underlying mechanisms for enhancing its efficient performance in cathodic protection systems. A few mechanisms have been proposed for the role of indium in the activation of Al-Zn-In anodes and there appears to be no general agreement on whether this element plays its depassivating role by modifying the bulk microstructure of the anode, chemical composition of its surrounding electrolyte or directly through doping the structure of the passive oxide film. These mechanisms have been critically reviewed to achieve a more comprehensive understanding of the role of indium in such applications. Moreover, the novel solidification processing called controlled diffusion solidification (CDS) has been introduced as an efficient way to surmount the poor castability of the anode alloy without any need for the addition of elements with detrimental effects on the electrochemical properties of the anode.

The optical and electrical properties are the two important dimensions of Indium oxide and its derivatives (indium tin oxide) and were well studied to understand the origin of wide electronic band gap and high electrical conductivity at room temperature. In 2 O 3 and its derivatives find many applications in electronic and optoelectronic domains based on the above properties. The recent discovery of ferromagnetism in In 2 O 3 at room temperature become a third dimension and lead to intensive research on enhancement of ferromagnetic strength by various means such as dopants and synthesis protocols and extrinsic parameters. The research lead to enormous experimental data and theoretical models proliferation over the past one decade with diverse insights into the origin of ferromagnetism in In 2 O 3 based dilute magnetic semiconductors. The experimental data and theoretical models of ferromagnetism in In 2 O 3 has been thoroughly surveyed in the literature and compiled all the data and presented for easy of understanding in this review. We have identified best chemical composition, geometry and synthesis protocols for strongest ferromagnetic strength and suitable theoretical model of magnetism has been presented in this review.

Notable aspects of the chemistry of complexes of polyether ligands including crown ethers, cryptands, glycols, glymes, and related polyether ligands with heavier group 13 and 14 elements are reviewed with a focus on results from 2005 to the present. The majority of reported polyether complexes contain lead(II) and thallium(I) but recent breakthroughs in regard to the preparation of low oxidation state reagents of the lighter congeners have allowed for the generation of complexes containing indium(I), gallium(I), germanium(II), and even silicon(II). The important roles of ligand size, donor types, and counter anions in regard to the chemical properties of the polyether complexes is highlighted. A particular focus on the structural aspects of the numerous coordination complexes provides a rationale for some of the spectacular contributions that such compounds have made to Modern Main Group Chemistry.

A variety of 5,6-dihydropyrazolo[5,1-a]isoquinolines is prepared by halocyclization of N-propargylic sulfonylhydrazones with indium trihalide.

A novel synthesis of α-aminonitriles is described via an indium-catalyzed three-component coupling reaction of alkynes, amines, and trimethylsilyl cyanide (Me3SiCN). Hydroamination of alkynes with a subsequent nucleophilic addition of Me3SiCN resulted in a novel approach to quaternary α-aminonitrile derivatives.

By applying carbonyl compounds as sources of alkyl groups to the indium-catalyzed reductive alkylation of indoles, a reliable and practical method capable of offering a wide range of alkylindoles with structural diversity has been developed. An important feature of this method is that the loading of the indium catalyst can be reduced by more than that of the original alkyne-based system.

The first indiumsilicate oxysulfide Ba2In2Si3O10S (1) was obtained by an alkali polychalcogenide flux method through a high-temperature solid-state reaction. It crystallizes in the non-centrosymmetric space group Pca21 (No. 29), with a = 23.060(6), b = 5.2954(6), c = 8.779(2) A, and Z = 4. Its three-dimensional (3D) framework is constructed from one-dimensional (1D) infinite ∞1[In2O7S2/2] double octahedral chains bridged by corner-sharing Si tetrahedral trimers [Si3O10]8–, yielding a 3D framework with the channels filled with Ba2+ cations along the b direction. It is unprecedented in that the two distorted indium octahedra in 1 face-share to form a [In2O7S2] dimer in indium oxides and oxide chalcogenides.

Various O and S-glycosyl esters and their corresponding acids are synthesized through a reaction of bromo sugar and benzyl glycolate in the presence of indium trichloride and indium tribromide as promoter. We discovered unprecedented catalytic effects of indium tribromide in glycosylation and hydrogenolysis in a one-pot operation. The sugar acid is a potential chiral auxiliary for the synthesis of biologically active compounds of diverse interests.

We describe how a reducing system composed of InI 3 and a hydrosilane efficiently and directly introduce elemental sulfur into the structure of dibenzyl sulfides via a nucleophilic substitution of benzyl alcohols. Also, we describe the application of this reducing system in the direct preparation of a dibenzyl selenide derivative with selenium.

An In(O-Ac)3—Ph-SiHMe2 system simultaneously promotes the hydrosilylation of the ketone and carboxylic acid functionality in 3-benzoylpropionic acids as well as the subsequent intramolecular cyclization of the iodinated intermediate formed furnishing tetralin derivatives in good to excellent yields.

Described herein is that the catalytic construction of N-substituted five- and six-membered lactams from keto acids with primary amines by reductive amination, using an indium/silane combination. This relatively benign and safe catalyst/reductant system tolerates the use of a variety of functional groups, especially ones that are reduction-sensitive. A direct switch from synthesizing lactams to synthesizing cyclic amines is achieved by changing the catalyst from In(OAc)3 to InI3. This conversion occurs by further reduction of the lactam using the indium/silane pair.

Synthesis of arenes substituted with two differently substituted-pyrrole moieties was investigated. A Paal-Knorr condensation reaction of nitroanilines with 1,4-diketone to nitrophenyl-1H-pyrroles followed by an indium-mediated reduction-triggered coupling reaction with another kind of 1,4-diketone resulted in two distinct pyrrole-containing arenes, variously substituted 1-((1H-pyrrol-1-yl)phenyl)-1H-pyrroles, in reasonable yield.

An indium(III)-promoted direct acylation of terminal alkynes using aldehydes leading to ynones was developed. In contrast to the previous addition reactions of alkynes to aldehydes, which provide propargylic alcohols, the oxidative coupling proceeded exclusively to afford alkynyl ketones. The products were likely generated through an Oppenauer oxidation of the indium propargylic alkoxide species by excess amounts of aldehydes.

Herein, a coupling reaction of enol ethers with silyl ketene imines in the presence of catalytic amounts of InBr3 and Me3 SiBr is described. Kinetic studies have revealed that an indium catalyst and Me3 SiBr accelerated the coupling process and the regeneration of the catalyst, respectively. Various types of enol ethers and silyl ketene imines are applicable. In addition, a formal synthesis of verapamil was achieved by using this novel coupling reaction.

The novel facile approach provides a new class of succinimide or phthalimide-derived azaspiro-γ-lactones with an exo-methylene lactam ring as potential drug candidates.

Transformation of the cyclobutenone products via thermal ring opening and oxidative cleavage of the silicon substituent is exemplified.

Indium(III) chloride is a more efficient catalyst than gold catalysts in dehydrative reactions of allylic alcohols with alcohols, thioacid, and thiophenols.

On treatment with indium metal in MeOH–THF, trityl groups undergo reductive removal from 1H-protected tetrazoles (including aliphatic, aromatic, and heteroaromatic substituents), affording the corresponding free tetrazoles in excellent yields, without any decomposition of the tetrazole ring or reduction of any other group.

A series of ZnInxS4+y (x=1.6, 2.0, 2.3, 2.6, 2.9, 3.1) photocatalysts were synthesized via a facile hydrothermal method and characterized by various analytical techniques, such as XRD, EDS, UV–vis DRS, SEM, TEM, BET and PL. The ZnInxS4+y photocatalysts had a similar crystal structure. With the increase of indium content, the absorption edges of ZnInxS4+y photocatalysts shifted to longer wavelength, their crystal sizes decreased firstly and then increased and the variation of the specific surface area and total pore volume was exactly opposite. Especially, when x=2.3, ZnIn2.3S4+y catalyst had smallest crystal size, largest specific surface area and total pore volume. Additionally, the morphology of ZnInxS4+y greatly depended on the contents of indium. The photocatalytic activity of ZnInxS4+y was evaluated by photocatalytic hydrogen production from water under visible light. The ZnIn2.3S4+y sample had the highest photocatalytic activity among these ZnInxS4+y photocatalysts and its hydrogen production rate was 363 μmol/g h.

An unusual multiple isocyanide insertion reaction with methyleneindolinone using indium(III) chloride as the catalyst has been disclosed. This strategy allows for the rapid construction of structurally complex spirooxindole in an efficient manner. The present protocol features mild conditions, atom economy, and broad substrate scope.

Hydroindation reaction of allenyl ketones with indium and indium chloride produces indium reagents (II), which undergo Pd-catalyzed cross-coupling reactions with aryl iodides, bromides, and triflates as well as cyclohexenyl triflates to form (Z)-α,β-unsaturated ketones predominantly.

The reaction tolerates a range of isatins/isatinimines and acrylates or aliphatic cyclic and acyclic enones.

An indium-catalyzed oxidative C—H alkylation and arylation of chromenes promoted by DDQ and a catalytic amount of In(OTf)3 is developed.

An efficient and economical method has been developed for the synthesis of pyrano[3,2-h]quinolines via an indium trichloride-catalyzed one-pot three-component reaction of 8-hydroxyquinoline with aromatic aldehydes and malononitrile/ethyl cyanoacetate under microwave irradiation.

The efficient protocol is not transferable to the benzylic addition to other types of ketone derivatives such as acetophenone and benzophenone.

Single crystals of Ba5In4Sb6 are grown from a reactive indium flux using a molar mixture of Ba:In:Sb of 3:30:5 (alumina crucible, 1173 K, 20 h; cooling to 773 K at a rate of 2 k/h).

The title compounds are obtained by a formal indium-catalyzed [2+2] cycloaddition between electron-deficient enynals and various alkynes.

A one-pot monoalkylation of benzene derivatives with aliphatic carboxylic acids having a variety of substituents with a combination of InI3, hydrosilane, and molecular iodine is reported.

Described herein is a direct approach to symmetrical thioethers from either aromatic carboxylic acids or aromatic aldehydes with elemental sulfur (S8) by using a reducing system combined with InI3 and 1,1,3,3-tetramethyldisiloxane (TMDS). This sulfidation does not require functionalized sulfur reagents, such as sulfides, disulfides, or metal sulfides, and it simultaneously forms two carbon–sulfur bonds in a single catalytic system.

An efficient pot and time economic ‘dry-media’ synthesis of pyrimidine core containing scaffolds by application of an indium triflate catalyzed carbon–carbon bond formation procedure through Diels–Alder reaction using microwaves is described. The method is associated with some attractive characteristics such as short reaction time, high yield of products, and recyclability of recovered catalyst from the reaction mixture.

Intermolecular additions of thiols to allenols via formal SN2′ selectivity to produce functionalized dienes are described. Although this dehydrative reaction was initially developed using gold(I) catalysis, indium(III) proves to be a far superior catalyst in terms of selectivity and substrate scope.

An operationally simple and efficient method for the synthesis of 2-alkynyl-3,3-dichloropyrrolidines from imines and readily available acetylenes is developed using indium(III) triflate as a Lewis acid catalyst.

The one-pot reduction-cyclization of 2-nitroanilines and 1,2-diketones to give quinoxalines was investigated. Using indium and an appropriate acid such as acetic acid or indium(III) chloride, various quinoxaline derivatives including 2,3-dialkylquinoxalines, 2,3-diphenylquinoxalines, 2,3-di-2-thiophenylquinoxalines, 2,3-di(pyridin-2-yl)quinoxalines, and dibenzo[ a , c ]phenazines were synthesized in moderate to excellent yield.

ConspectusA myriad of natural and/or biologically active products include nitrogen- and oxygen-containing saturated heterocycles, which are thus considered as attractive scaffolds in the drug discovery process. As a consequence, a wide range of reactions has been developed for the construction of these frameworks, much effort being specially devoted to the formation of substituted tetrahydropyrans and piperidines. Among the existing methods to form these heterocycles, the metal-catalyzed heterocyclization of amino- or hydroxy-allylic alcohol derivatives has emerged as a powerful and stereoselective strategy that is particularly interesting in terms of both atom-economy and ecocompatibility. For a long time, palladium catalysts have widely dominated this area either in Tsuji–Trost reactions [Pd(0)] or in an electrophilic activation process [Pd(II)]. More recently, gold-catalyzed formation of saturated N- and O-heterocycles has received growing attention because it generally exhibits high efficiency and dia...

The presented reaction selectively delivers the 6-endo product, namely 2H-chromenes, and succeeds with substrates equipped with terminal or internal alkynes, tolerates various electron-rich and electron-deficient substituents on the benzene as well as the alkyne moiety.