CRYSTAL STRUCTURES OF TWO BARIUM 2–THIOBARBITURATE COMPLEXES
N. N. Golovnev1, M. S. Molokeev2
1Siberian Federal University, Krasnoyarsk, Russia
ngolovnev@sfu-kras.ru
2Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, Russia
Keywords: crystal structure, barium thiobarbiturate, hydrogen bonds, p-p interaction
Abstract
The crystal structures of [Ba(H2O)2(μ3–HTBA)2]n (I) and [Ba(μ2–H2O)(H2O)2(μ4–HTBA)(HTBA)]n ×2nH2O (II), where H2TBA is 2–thiobarbituric acid C4H4N2O2S, are determined. Crystallographic data are as follows: for I, a = 6.8730(1) Å, b = 16.6640(2) Å, c = 11.8504(2) Å, V = 1357.24(4) Å3, space group Pnma, Z = 4; for II, a = 9.134(1) Å, b = 9.853(1) Å, c = 10.020(1) Å, a = 103.674(2)°, b = 99.491(2)°, g = 101.683(2)°, V = 836.3(2) Å3, space group P–1, Z = 2. In I, the Ba2+ ion coordinates 6μ3–HTBA– ions and two terminal water molecules with the formation of a distorted square antiprism. The antiprisms are linked with each other into infinite chains by the edges of S atoms. In II, the Ba2+ ion coordinates four water molecules and 5 HTBA– ions forming a three-cap trigonal prism. Two BaO8S prisms have four common vertices of O atoms from two m2–H2O and two μ4–HTBA–; they are organized into layers with other pairs. The structures are stabilized by intermolecular hydrogen bonds and the p–p–interaction of HTBA– ions.
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