New volatile heteroleptic complex of copper(II): Comparison of two polymorphs

• Published in: Polyhedron 2013-01, Vol.49 (1), p.1-6
• Main Authors: Krisyuk, V.V., Baidina, I.A., Korolkov, I.V., Semyannikov, P.P., Stabnikov, P.A., Trubin, S.V., Turgambaeva, A.E.
• Format: Article
• Language: English
• Subjects: Chelates; Copper(II) β-diketonate; Copper(II) β-ketoiminate; Crystal structure; Heteroleptic complexes; N,O ligands; Polymorphism; Thermal stability; Volatility
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2012.09.038

Cu(ki)(hfa) as a heteroleptic compound containing simultaneously β-ketoiminate and a diketonate ligand appeared to be thermally stable to the conversion into homoleptic complexes. This compound is volatile and can exist in two polymorphs: monomeric α-modification and dimeric β-modification. A new heteroleptic complex Cu(ki)(hfa)=Cu(ONC5H8)(O2C5F6H), where ki=pentane-2-imino-4-onato (ketoiminate) and hfa=1,1,1,5,5,5-hexafluoro-pentane-2,4-dionato (hexafluoroacetylacetonate), has been obtained and its two crystalline modifications were characterized. The isolated polymorphs have different crystal symmetry and crystal packing of the molecules. Crystal data for the monomeric α-modification are: a=16.4648(14), b=16.4648(14), c=4.9308(6), space group P4¯, Z=4, Dcalc=1.832g/cm3. Crystal data for the dimeric β-modification are: a=6.9718(14), b=8.5694(17), c=11.859(2), α=87.81(3)°, β=77.96(3)°, γ=68.14(3)°, space group P1¯, Z=2, Dcalc=1.906g/cm3. Results of the TG/DTA study of the compound in the condensed phase and the mass spectrometric investigation in the vapor phase are discussed. The reported compound is thermally stable and sublimes in vacuum without decomposition into homoleptic complexes. For both polymorphs the temperature dependence of the saturated vapor pressure was measured by the Knudsen effusion method with the mass spectrometric recording of the gas phase composition within the range 322–343K.