The molecular structure of tris-2,2,6,6-tetramethyl-heptane-3,5-dione indium: gas-phase electron diffraction and quantum chemical calculations

Abstract

The molecular structure of tris-2,2,6,6-tetramethyl-heptane-3,5-dione indium, or In(thd)3, has been determined by gas-phase electron diffraction monitored by mass spectrometry (GED/MS) and quantum chemical (DFT) calculations. Both the DFT calculations and the GED data collected at 387(8) K indicate that the molecules have D 3 symmetry with a distorted anti-prismatic InO6 coordination geometry. According to GED refinements, the twist angle θ, i.e. the angle of rotation of the upper and lower O3 triangles in opposite directions relative to their positions in a regular prism is θ = ±24.9(1.2)° and the bond distances (r h1) in the chelate ring are In–O = 2.127(4) A, C–O = 1.268(3) A and C–C = 1.411(3) A, respectively. The DFT calculations yielded structure parameters in close agreement with those found experimentally.