Structure and Thermal Decomposition of Nd(III), Gd(III) and Tb(III) 2-Thiobarbiturates

• Published in: Russian journal of inorganic chemistry 2019-09, Vol.64 (9), p.1146-1151
• Main Authors: Golovnev, N. N., Molokeev, M. S., Sterkhova, I. V.
• Format: Article
• Language: English
• Subjects: Bridging; Chemical bonds; Chemistry; Chemistry and Materials Science; Coordination Compounds; Crystals; Gadolinium; Hydrogen bonds; Inorganic Chemistry; Single crystals; Thermal decomposition; Thiobarbituric acid; Water chemistry
• ISSN: 0036-0236; 1531-8613
• DOI: 10.1134/S0036023619090134

Complexes [Ln 2 (H 2 O) 6 (μ 2 -Htba−O,O') 4 (Htba−O) 2 ] n (Ln = Tb ( I ), Gd ( II ), Nd ( III ); and H 2 tba is thiobarbituric acid) have been synthesized. According to single-crystal X-ray diffraction, monoclinic crystals of I–III are isostructural. They contain three independent Htba – ions (one terminal and two bridging) and two independent Ln 3+ ions. Six Htba – ligands (two terminal and four O,O'-bridging) and two water molecules are coordinated to one Ln 3+ ion, and four O,O'-bridging Htba – ions and four water molecules are coordinated to the other Ln 3+ ion to form square antiprisms. The antiprisms are bound by Htba – bridging ions into layers. Numerous hydrogen bonds and π–π interactions stabilize the structures of the compounds. Thermal decomposition of complexes I and II performed in air results in mixtures of oxides and oxysulfates, whereas complex III forms Nd 2 O 2 SO 4 .