The synthesis and deep purification of GaEt3. Reversible complexation of adducts MAlk3 (M = Al, Ga, In; Alk = Me, Et) with phenylphosphines

Optimal parameters of organomagnesium technique of synthesis of triethylgallium have been defined. Various techniques of deep purification of triethylgallium to the extent required in metalorganic vapor-phase epitaxy MOVPE have been studied: by way of residue ether displacement through high-performance rectification and interaction with high pure aluminum and gallium trichloride, and by way of reversible complexation with triphenylphosphine, 1,3-bis(diphenylphosphine)propane and 1,5-bis(diphenylphosphine)pentane. Advantages and disadvantages of each technique have been identified. We have shown high performance of adduct purification technique covering trimethyl and triethyl derivatives of aluminum, gallium and indium. The structure of donor–acceptor complexes between metal alkyls and the above-mentioned phosphines have been verified using H and 31P NMR spectroscopy and X-ray studies, as well as quantum chemical calculations. Thermal stability of triethylgallium and oxidation of its adducts with phosphines have been studied.

This paper sets forth research results for the complexation of Ph3P, Ph2P–(CH2)n–PPh2, n = 3.5 with MAlk3, M = Al, Ga, In; Alk = Me, Et. These complexes can be used for adduct purification of MAlk3 for their further use in MOVPE.equation(1)PPh3+MAlk34-6a,b⇌Ph3P:MAlk37a-fequation(2)Ph2P−(CH2)n−PPh21,2+MAlk34-6a,b⇌(CH2)n(−PPh2:MAlk3)28a-f,9a-fwhere M = Al (4, а,b), Ga (5, c,d), In (6, e,f); Alk = СН3 (a,c,e), C2Н5 (b,d,f); n = 3 (8), 5 (9).Figure optionsDownload as PowerPoint slideHighlights
► Organomagnesium technique of synthesis of GaEt3 has been optimized.
► GaEt3 has been successfully purified to microelectronic grade by various techniques.
► Adduct purification with phenylphosphines is the most efficient technique.
► 14 new adducts MAlk3 (M = Al, Ga, In; Alk = Me, Et) with phenylphosphines.
► Properties of adducts change depending on properties of their components.