Indium amides

In 1980 only a handful of indium amides had been characterized and only one X-ray crystal structure had been published. During the ensuing period the investigation of indium amides has been spurred by their possible applications in technology. In addition, there has been an interest in low coordinate and oxidation state compounds. Both indium amides  

The neutral parent amido species [In(NH2)3] was synthesized by reaction of KNH2 with Ini, in liquid ammonia.Its manner of polymerization in the solid is unknown because diffraction studies were inconclusive as a result of crystal twinning. It was shown to decompose cleanly and quantitatively at moderate temperature to yield InN with liberation 

The isolation of neutral monomeric and stable indium amides in the solid state is only feasible with use of bulky substituents, and the synthesis is usually accomplished by a 

Higher metal coordination numbers are also observed in the distorted square pyramidal indium(lll) amides [MeIn N(Me)(2-py) 2]2 ° and [MeIn 2-(N(CH2Ph)aj de(2-py) 2] in which the bidentate ligands occupy equatorial positions (mean In—N bond lengths are 

14 and 2.16 A, respectively mean In—N(py) bond lengths are 2.34 A) and the methyls have apical positions with In—C distances of 2.146(2) and 2.169(2) A, respectively. A distorted trigonal bipyramidal geometry is observed in [In N(H)Dipp 3(py)2], in which the py groups have axial positions (In-N bond lengths are 2.421 (4) and 2.460(4) A) and the three amido ligands are in equatorial positions with shorter In-N distances between 2.11 and 2.12 A. 

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H2lnNH2 has been generated in argon matrices and characterized using IR spectroscopy. Univalent and divalent indium amide derivatives are also observed under these conditions. 

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. 

Carbon and oxygen impurities are below 1 atom %. Based on the gases that are eliminated from this precursor, it is clear that the nitrogen source in the deposition is the azide group. It is found that the best films are formed under vacuum without additional sources of nitrogen (such as N2 and NH3). Homoleptic indium amides can be used when volatilized in the presence of NH3 . ... 

Squaric acid forms salts with aluminium, gallium, and indium. Amidation of squaric acid gives not only the 1,3- but also, the 1,2-diamides, which can be further acylated on the nitrogen. The amides, esters, and chlorides can be transformed into thiosquarates by the action of HS and cyclobutene dications can be obtained from the l,2-dithio-3,4-diamide. Neuse and Green have examined further arylation reactions of squaryl chlorides from which a variety of substituted cyclo-butenones may be obtained. Phosphine derivatives of the squarate system have also been reported. ... 

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