Geometrical isomers of tris(beta-diketonato)metal(III) complexes for M = Cr or Co: Synthesis, X-ray structures and DFT study

Abstract

Solid state crystal data of three tris(b-diketonato)metal(III) complexes (M = Cr or Co), representative of the three different molecular symmetries that these complexes can obtain, namely D3, C3 or C1 symmetry, are presented and compared with related experimental structures. Density functional theory calculations show that both fac and mer isomers of tris(b-diketonato)metal(III) complexes containing unsymmetrical b-diketonato ligands can exist, in agreement with experimental NMR data. The orbital ordering for both the S = 3/2 [Cr(acac)3] and S = 0 [Co(acac)3] (Hacac = acetylacetone) complexes in order of increasing orbital energy is: dxy < dxz; dyz < dz2 ; dx2 y2 .