Gas‐Phase Structures of Potassium Tetrakis(hexafluoro‐ acetylacetonato) Lanthanide(III) Complexes [KLn(C(5)HF(6)O(2))(4)] (Ln=La, Gd, Lu)

The molecular structures of potassium tetrakis(hexafluoroacetylacetonato)lanthanide(III) complexes [KLn(hfa)(4)] (Ln=La, Gd, Lu; hfa=C(5)HF(6)O(2),) were studied by synchronous gas‐phase electron diffraction/mass spectrometry (GED/MS) supported by quantum‐chemical (DFT/PBE0) calculations. The compounds sublime congruently and the vapors contain a single molecular species: the heterobinuclear complex [KLn(hfa)(4)]. All molecules are of C (1) symmetry with the lanthanide atom in the center of an LnO(8) coordination polyhedron, while the potassium atom is coordinated by three ligands with formation of three K−O and three K−F bonds. One hfa ligand is not bonded to the potassium atom. Topological analysis of the electron‐density distributions confirmed the existence of ionic‐type K−O and K−F bonding. The structures of the free [KLn(hfa)(4)] molecules are compared with those of the related compounds [KDy(hfa)(4)] and [KEr(hfa)(4)] in their crystalline state. The complex nature of the chemical bonding is discussed on the basis of electron‐density topology analyses.