Purification of dialkylzinc precursors using tertiary amine ligands
Tertiary amines are useful for the production of high purity low-oxygen content R2Zn dopant sources. Trace oxygen levels in Me2Zn are significantly reduced by formation of the Me2Zn.NEt3 adduct, which is a more controllable and reproducible source than Me2Zn/H2 gas mixtures. Me2Zn and Et2Zn form 2∶1 adducts with the macrocyclic tertiary amines 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (N4-aza crown) and 1,4,7,10,13,16-hexamethyl-1,4,7,10,13,16-hexaazacyclooctadecane (N6-aza crown), and the structure of these compounds has been determined by single crystal x-ray crystallography. Mild thermal dissociation of R2Zn-aza crown adducts yields base-free R2Zn, giving them potential applications in the purification of Me2Zn and Et2Zn dopant sources for the MOVPE of III–V materials.