Crystal structure and properties of polymeric hexaaqua-hexakis-(2-thiobarbiturato)-disamarium(III)

Abstract

The structure (CIF file CCDC No. 1401886) of the hexaaqua-hexakis(2-thiobarbiturato)-disamarium [Sm₂(H₂O)₆(HTBA)₆]_n polymeric complex (I), where H₂ТВА is 2-thiobarbituric acid, is determined; its thermal decomposition and IR spectrum are studied. The crystals of I are monoclinic: a = 14.072(1) Å, b = 10.0842(6) Å, c = 15.323(1) Å, β = 110.408(2)°, V = 2037.9(2) ų, space group P2/n, Z = 2. All three independent thiobarbiturate anions HTBA^– coordinate to Sm³⁺ through oxygen atoms. To one of independent Sm³⁺ ions six (two terminal and four bridging) HTBA^– ions and two water molecules are coordinated; the second is bonded with four bridging HTBA^– and four water molecules, forming square antiprisms. The bridging HТВА–anions arrange antiprisms in layers. The structure is stabilized by hydrogen bonds and a π–π interaction between the HТВА^– ions. The topology of the polymer network of I is analyzed.