Molecular structure of tris(dipivaloylmethanato)lutetium(iii) studied by gas electron diffraction and ab initio and DFT calculations.

Combined gas electron diffraction/mass spectrometry (GED/MS) was used to determine the molecular structure of tris(dipivaloylmethanato)lutetium(III), Lu(dpm)(3)(dpm = 2,2,6,6-tetramethyl-heptane-3,5-dionato). Up to about 520-570 K the vapour consisted only of molecules Lu(dpm)(3). The experimental data recorded at 408(5) K indicate that the molecules have D(3) symmetry. The bond distances (r(h1)) in the chelate ring are Lu-O 2.197(6) Angstrom, C-O 1.270(4) Angstrom and C-C 1.390(6) Angstrom . Theoretical computations at the HF and DFT levels with basis sets up to 6-311G* afford structures similar to those found experimentally, with a distorted LuO(6) antiprism.