NEW VOLATILE BETA-DIKETONATE COMPLEXES OF BARIUM WITH STERICALLY HINDERED METHOXY-BETA-DIKETONES AS PRECURSORS FOR CVD

The new beta-diketones with a methoxy group of the type (R(1)R(2))C(OC H3)COCH(2)COR(3) and their barium complexes have been synthesized. The barium beta-diketonates obtained were identified and characterized by elemental, IR and Raman spectroscopic analyses. TG, DTG and DTA analy ses carried out in vacuo and at atmospheric pressure have allowed the determination of the relative volatility and thermal stability of thes e barium complexes. The influence of the methoxy group, by type of sub stituent in the ligand, has been investigated by mass spectrometry. It has been found that the introduction of bulky end substituents into t he ligand does not reduce the maximal oligomerization degree of barium beta-diketonates in the gas phase. Copyright (C) 1996 Elsevier Scienc e Ltd