Investigation of the structure and energy of β-diketonates. Communication XIV. Overheated vapour composition and the molecular structure of monomeric yttrium tris-hexafluoroacetylacetonate, Y(C5O2HF6)3, from simultaneous gas-phase electron diffraction and mass spectrometric experiment

Simultaneous electron diffraction and mass spectrometry along with a quantum chemical (DFT/B3LYP) calculation are applied to study the molecular structure of yttrium tris-hexafluoroacetylacetonate, Y(hfa)3. The superheating of the vapor in a double two-temperature effusion cell shows that up to a temperature of ∼200 deg C ions containing from one to three metal atoms are formed, and the most intensive ion has the stoichiometry of (Y2L5)+ at a temperature below ∼120 deg C. The monomer starts to noticeably decompose at temperatures above 330 deg C. The electron diffraction patterns of monomers are obtained at T exp = 208(5) deg C. According to the results of theoretical and experimental investigations, Y(hfa)3 molecule has D 3-symmetry. The rotation angle of triangular O-O-O faces with respect to their position in the regular prism is equal to 14.4(1) deg. The values of internuclear distances and valence angles (r h1-geometry) are: r(Y-O)=2.259(6) A, r(C-O)=1.263(6) A, r(C-Cr)=1.413(4) A, r(C-CF)=1.531(4) A, r(C-F)=1.344(3) A, O-Y-O=75.2(2) deg, O-C-CF=113.8(2) deg, C-CF-F=112.4(2) deg. The results of quantum chemical calculations are well consistent with the experimental data