COPPER(II) COMPLEXES WITH SCHIFF BASES: STRUCTURES AND THERMAL BEHAVIOR
S. I. Dorovskikh, N. V. Kuratieva, S. V. Tkachev, S. V. Trubin, P. A. Stabnikov, N. B. Morozova
Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: ligands with Schiff bases, copper(II) complexes, single crystal X-ray diffraction analysis, thermogravimetry
Abstract
Ligands with Schiff bases are obtained in the condensation of propylenediamine (pda) or 2,2–dimethylpropylenediamine (dmpda) with acetylacetone (Hacac) in the 1:2 molar ratio. The ligands are characterized by the elemental analysis methods, Tmelt = 90–92 °C for pda(Hacac)2 (pda(acac)2 is N,N'-propylene-bis(acetylacetoniminato) (2–)), Tmelt = 84–86 °C for dmpda(Hacac)2 (dmpda(acac)2 is N,N'–2,2–dimethylpropylene-bis(acetylacetoniminato) (2–)). The tautomerism of the ligands is established by the single crystal X-ray diffraction (XRD) analysis, IR spectroscopy, and 1H, 13C NMR spectrometry. The synthesized complexes [Cu(pda(acac) 2)] (1), Tmelt = 121–122 °C and [Cu(dmpda(acac)2)] (2), T melt = 156–158 °C are studied by the XRD method. In both complexes, copper atoms have a planar square geometry, and the chelate bond lengths and angles are: Cu–O ≈ Cu–N 1.903(2)–1.942(3) Å, ∠ O–Cu-N = 94.44(12)–94.99(12)° for 1 and Cu–O ≈ Cu-N 1.909(1)–1.943(2) Å, ∠ O–Cu–N = 94.63(6)° for 2. By the thermogravimetric method it is found that both complexes can be passed practically quantitatively into the gas phase.
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