H. Guillon et al., Synthesis, characterisation and X-ray structures of yttrium, barium and copper(II) beta-ketoesterate complexes, INORG CHIM, 304(1), 2000, pp. 99-107
beta-Ketoesterates derivatives M(mpa)(x) (M = Y, Ba, Cu; mpaH = methylpival
oylacetate; x = 2 or 3) were prepared by ligand exchange reactions starting
from methoxides (M = Ba, Cu) or from tristrimethylsilylamide (M = Y) deriv
atives. Decomplexation of the oligomeric and non-volatile Ba and Y species
was achieved by various Lewis bases. Adducts Y(mpa)(3)L [L = tmeda (N,N,N',
N'-tetramethylethane- 1,2-diamine), bipy (2,2'-bipyridine)] and Ba(mpa)(2)L
[L = diglyme, 18-crown-6 ether; pmdta = N,N,N',N',N"-pentamethylethylenetr
iamine and [Ba(mpa)(2)(tmedta)(2)] were obtained. All compounds were synthe
sised in high yield and characterised by elemental analyses, H-l NMR, FT-IR
and TGA. The structures of [Ba(mpa)(2)(tmeda)(2)] and [Y(mpa)(3)(bipy)] we
re established by single crystal X-ray diffraction. The metals are eight-co
ordinated with a slightly distorted square antiprismatic surrounding. The y
ttrium complexes sublime as adducts. The barium complexes, by contrast, are
dissociated in the vapour phase. Better solubility properties in polar and
non-polar with respect to the 2,2,6,6-tetramethylheptane-3,5-dionates anal
ogues were observed especially for the copper species. These compounds are
thus potential metal-oxide precursors for liquid injection MOCVD using solv
ents such as hexane or diglyme. (C) 2000 Elsevier Science S.A. All rights r
eserved.