Synthesis, AACVD and X-ray crystallographic structures of group 13 monoalkoxometallanes

Abstract

The group 13 monoalkoxometallanes [Me2Ga(OC(CH3)2CH2OMe)]2 (1) and [Me2In(OCH(CH3)CH2OMe)]2 (2), incorporating donor functionalised alkoxides, were synthesised from the reaction of GaMe3 or InMe3 with ROH (R = C(CH3)2CH2OMe (1); R = CH(CH3)CH2OMe (2)) in toluene. X-ray crystallography showed that both compounds adopt dimeric structures with a planar M2O2 ring, and each group 13 atom is coordinated in a distorted trigonal bipyramidal geometry. The AACVD reaction of GaMe3 and ROH (R = C(CH3)2CH2OMe, CH2CH2OMe, CH2CH2NMe2) resulted in the formation of thin films of Ga2O3 on glass substrates at 450 • C. The gallium oxide films were analyzed by scanning electron microscopy, X-ray powder diffraction, energy dispersive analysis of X-rays, wavelength dispersive analysis of X-rays and X-ray photoelectron spectroscopy. This CVD technique offers a rapid, convenient route to Ga2O3, which involves the in situ formation of dimethylgallium alkoxides, of the type [Me2Ga(µ-OR)]2 similar to compound 1.

Effect of In–CNHC Bonds on the Synthesis, Structure, and Reactivity of Dialkylindium Alkoxides: How Indium Compares to Gallium

“…Interestingly, the presence of the bulky alkoxide group resulted in this case in asymmetric In 2 O 2 bridges (Figure ). Prior to the reactivity of 5 with the NHC, it must be noted that In–O bonds (2.152, 2.176, 2.178, and 2.191 Å) of the In 2 O 2 central ring were slightly longer in comparison with [Me 2 In­(μ-OCH­(Me)­CH 2 OMe)] 2 (2.107, 2.179 Å); however, they were significantly shorter in comparison with rac -[Me 2 In­( melac )] 2 (2.157, 2.216 Å) and [Me 2 In­(( S )- melac )] 2 (2.156, 2.157, 2.217, and 2.231 Å) . Notably, the significant tension within the In 2 O 2 central ring, evidenced by In–O–In–O torsion angles of 14.32–14.67° (Figure ), in comparison with [Me 2 In­(μ-OCR­(Me)­CH 2 OMe] 2 (R = H, Me) (0°), as well as rac -[Me 2 In­( melac )] 2 (0°) and [Me 2 In­(( S )- melac )] 2 (4.9°), could facilitate the breaking of In 2 O 2 bridges and the stabilization of Me 2 In­(OCPh 2 Me)­(NHC) complexes (see below).…”

Aerosol-assisted delivery of precursors for chemical vapour deposition: expanding the scope of CVD for materials fabrication

“…This is most notable within transparent films and has been particularly observed in the deposition of gallium oxide. 20,21 It is, however, unclear whether this contamination is a result of carbon retention from the solvent or from the precursor and the colouration can be easily removed by annealing in air, producing transparent films. The depositions of niobium and tantalum sulphide 18 and titanium dioxide 19 carried out using chlorinated solvents, namely dichloromethane and chloroform respectively, have shown no evidence of chlorine contamination.…”

“…This is in contrast to the deposition of Ga 2 O 3 via AACVD of dialkylalkoxogallanes of the type [R 2 Ga-(OR′)] 2 , which produced grey or brown films attributable to the retention of a Ga-C bond. 14,21,22,24,72 Indium oxide. The production of indium oxide (In 2 O 3 ) thin films by CVD methods has been limited due to the unavailability of suitable precursors with high vapour pressures and low decomposition temperatures.…”

Gallium Hydride Complexes Stabilised by Multidentate Alkoxide Ligands: Precursors to Thin Films of Ga2O3 at Low Temperatures

“…The most commonly reported co‐ligands are alkyl groups (Me, Et) resulting from the reaction of donor‐functionalised alcohol with trialkylgallium reagents (Scheme ) 12. 13 Although both mono‐ and bis‐substituted alkoxides can be made by this method, only the former can be reliably synthesised in good yield 14. The other common co‐ligand that has been reported is chloride, originating either from 1) the direct reaction of alkali metal alkoxides with GaCl 3 or 2) the reaction of alcohols with chlorogallium amide complexes (Scheme ) 11.…”