Crystal Chemical Study of Two Scandium(III) Complexes with Pivaloyltrifluoroacetone
A scandium(III) tris-(pivaloyltrifluoroacetonate) complex [Sc(ptac)3] is synthesized, purified, and characterized by the elemental analysis, IR spectroscopy, and the TG/DTA technique. The complex is a highly volatile and low-melting compound that is stable in air and to heat. Slow evaporation of the mother ethanol liquor at room temperature leads to the growth of single crystals of a mixed-ligand complex with an alcohol molecule: [Sc(EtOH)(ptac)3]. By single crystal X-ray diffraction at a temperature of 150(2) K the [Sc(ptac)3] and [Sc(EtOH)(ptac)3] structures are solved. The crystallographic data are: for C24H30F9O6Sc space group P-1, a = 9.1565(2) Å, b = 9.6854(3) Å, c = 17.3271(4) Å, β = 79.927(1)°, V = 1465.79(7) Å3, Z = 2, dcalc = 1.428 g/cm3, R = 0.041; for C26F9O7Sc space group P-1, a = 9.9376(3) Å, b = 13.0243(4) Å, c = 13.2743(4) Å, β = 111.932°, V = 1575.85(8) Å3, Z = 2, dcalc = 1.426 g/cm3, R = 0.048. Both structures are composed of neutral molecules; the metal atom coordinates six oxygen atoms of three ligands of β-diketone ([Sc(ptac)3]) and additionally an oxygen atom of the ethanol molecule ([Sc(EtOH)(ptac)3]). Tert-butyl and trifluoromethyl substituents in both complexes are oriented so that they create a facial isomer. The Sc-O distances are within 2.07–2.11 Å in [Sc(ptac)3], and in [Sc(EtOH)(ptac)3] they are within 2.10–2.24 Å. In the crystals of both compounds, the molecules are linked by only van der Waals interactions, forming a pseudo-layered structure with a hexagonal arrangement inside the layer. Six shortest Sc⋯Sc distances in [Sc(ptac)3] are within 8.34–10.42 Å. In [Sc(EtOH)(ptac)3], a distorted hexagonal packing has an average parameter of ~9.5 Å.
Keywordsscandium pivaloyltrifluoroacetone synthesis single crystal X-ray diffraction analysis TG/DTA MOCVD precursor
Unable to display preview. Download preview PDF.
The authors are grateful to O.A. Plyusnina and I.V. Korolkov for performing TG and powder X-ray diffraction experiments respectively.
The work on the synthesis, purification, and characterization of [Sc(ptac)3] was supported by Russian Foundation for Basic Research grant No. 18-08-01105_a.
The single crystal X-ray diffraction analysis and the isolation of single crystals were performed within the State Contract of the Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences for basic scientific research.
Conflict of Interests
The authors declare that they have no conflict of interests.
- 12.Bruker AXS Inc. APEX2 (Version 1.08), SAINT (Version 7.03), and SADABS (Version 2.11). Bruker Advanced X-ray Solutions, Madison, Wisconsin, USA, 2004.Google Scholar
- 18.E. G. Zaitseva, I. A. Baidina, P. A. Stabnikov, S. V. Borisov, and I. K. Igumenov. J. Struct. Chem., 1990, 31, 184.Google Scholar