Synthesis and purification of trimethylgallium for MOCVD: molecular structure of (KF)4·4(Me3Ga)

✍ Scribed by Kazimierz B. Starowieyski; Andrzej Chwojnowski; Krzysztof Jankowski; Janusz Lewiński; Janusz Zachara

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 79 KB
• Volume: 14
• Category: Article
• ISSN: 0268-2605
• DOI: 10.1002/1099-0739(200010)14:10<616::aid-aoc47>3.0.co;2-t

✦ Synopsis

Trimethylgallium was obtained from a 3:1 molar mixture of Me 2 AlCl (1) and GaCl 3 (2) only in the presence of NaCl. The mechanism of the reaction was traced. It is postulated that the gallium-aluminium dimers Cl n Me 2Àn AlCl 2 GaCl m Me 2Àm (m and n = 0, 1 or 2), formed in consecutive alkylation steps, do not participate in further alkyl-chlorine exchange. NaCl splits the dimers that form the precipitate of Na[Me-AlCl 3 ] (3), thus liberating Me n GaCl 3Àn which, on further alkylation by Me 2 AlCl, finally yields Me 3 Ga. For an MOCVD application, it is purified through a complex with KF, which under vacuum decomposes at 180-300 °C, to yield a product contaminated by less than 1 ppm of the total impurities. The X-ray study of the complex reveals a tetrameric, highly symmetrical heterocubane of formula (KF) 4 Á4(Me 3 Ga).