Synthesis and molecular structures of cobalt(II) β-diketonate complexes as new MOCVD precursors for cobalt oxide films

Adducts of cobalt(II) 2,4-pentanedionate (acac) and 2,2,6,6-tetramethyl-3,5-heptanedionate (thd) with TMEDA (N,N,N',N'tetramethyl-1,2-diaminoethane) and aminoalcohols, namely 1-dimethylamino-2-propanol (DMAPH) and 2-dimethylaminoethanol (DMAEH), have been synthesized and characterized by elemental analyses, FT-IR, H-1 NMR, mass spectrometry and TGA. The molecular structures of Co(acaC)(2)(TMEDA) (1) and [Co(acaC)(2)(DMAPH)](2) (2) have been determined by single-crystal X-ray diffraction. 1 is monomeric while 2 is dimeric with two molecules linked by hydrogen bonds (O-H-O distance 2.708 Angstrom av.). The most volatile and stable new adducts Co(acaC)(2)(TMEDA) and Co(thd)(2)(TMEDA) have been studied as precursors for cobalt oxide deposition by liquid injection MOCVD in DME on monocrystalline LaAlO3 and Si substrates. Films were characterized by XRD and XPS. These preliminary MOCVD experiments showed that epitaxial Co3O4 films can be obtained by using both new precursors. (C) 2003 Elsevier Ltd. All rights reserved.