A. Yu. Rogachev

The composition of saturated and superheated vapors and molecular structure of Lu(C5O2HF6)3

The molecular structure of lutetium tris-hexafluoroacetylacetonate Lu(hfa)3 was studied in a synchronous electron diffraction and mass spectrometric experiment and quantum-chemically by the HF and DFT/B3LYP methods. Saturated vapor over Lu(hfa)3 was found to be oligomerized to a substantial extent. The mass spectrum of saturated Lu(hfa)3 vapor was studied over the temperature range 76–100°C; it contained peaks of ions with one to three metal atoms. The peak of the highest intensity corresponded to the M2L5+ stoichiometry. It was found in experiments with vapor superheating in a double two-temperature effusion cell that oligomeric forms disappeared above 150°C, whereas the decomposition of the monomeric form became noticeable above 250°C. The results obtained in theoretical and experimental studies allowed us to determine the structure of the Lu(hfa)3 molecule.

Mixed-ligand complexes based on asymmetric gadolinium β-diketonates: Synthesis, crystal structure, and theoretical modeling

AbstractMixed-ligand complexes of asymmetric gadolinium β-diketonates with 2,2′-bipyridyl (Bipy)—[Gd(Pa)3(Bipy)] (HPa is pivaloylacetone) (I) and [Gd(Pta)3(Bipy)] (HPta is pivaloyltrifluoroacetone) (II)-have been obtained by direct interaction of initial reagents and their structures have been studied by X-ray crystallography. Crystals of I are monoclinic: a = 9.536(1) Å, b = 15.037(1) Å, c = 13.280(1) Å, β = 109.56(1)°, V = 1798.7(3) Å3, Z = 2, space group P21. Crystals of II are triclinic: a = 9.6696(17) Å, b = 12.1348(9) Å, c = 18.243(3) Å, α = 100.257(12)°, β = 103.997(2)°, γ = 101.438(11)°, V = 1977.4(5), Z = 2, space group P

Synthesis, crystal structure and thermal behaviour of [La(hfa)3(Phen)2] (hfa = hexafluoroacetylacetonate, Phen = o-phenanthroline)

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Theoretical Modeling of the Structures and Properties of Lanthanum Complexes with Substituted Acetylacetones

. The coordination polyhedron of the central gadolinium atom in I and II is a distorted square antiprism formed by six oxygen atoms of the three β-diketonate ligands (av. Gd-O, 2.35(2) and 2.351(5) Å in I and II, respectively) and two nitrogen atoms of the Bipy ligand (av. Gd-N, 2.47(2) and 2.584(7) Å in I and II, respectively). Although the molecular structures of these complexes are similar, they have different crystal packings. In II, the planes of the Bipy ligands of neighboring molecules related by an inversion center are bound by stacking interaction (the distance between the Bipy planes is 3.45 Å). The structure and properties of these mixed-ligand complexes have been discussed based on the results of quantum-chemical density functional theory calculations (DFT/B3PW91). The nature of the substituents in the β-diketonate ligand has an effect on the structure and properties of the complexes. The correlation between the Gd-Dik and Gd (Dik)3-Bipy bond energies has been studied.