Poly[[pentaaquabis(μ<sub>3</sub>-hydrogen squarato)barium] monohydrate]

Trifa, Chahrazed; Bouhali, Amira; Bouacida, Sofiane; Boudaren, Chaouki; Mérazig, Hocine

doi:10.1107/s1600536813014736

Cited by 2 publications

(1 citation statement)

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“…With regard to alkaline metal squarates, few reports are found, among which poly[[pentaaquabis( 3 -hydrogen squarato)bar- ISSN 2053ISSN -2296 # 2019 International Union of Crystallography ium] monohydrate] is significant. In this complex, the Ba atoms are joined by bridging through a trans bis-monodentate mode and five water molecules are coordinated forming a slightly distorted tricapped trigonal prism (Trifa et al, 2013). Another article reports that the structure of calcium squarate, [Ca(C 4 O 4 ) 2 (H 2 O) 2.5 ], which crystallized in the space group I42d with the Ca 2+ ion coordinated to six squarate O atoms (Robl & Weiss, 1987).…”

Section: Introductionmentioning

confidence: 99%

New barium, strontium and strontium-doped barium squarates: synthesis, crystal structures and DNA/BSA binding, antioxidant and in vitro cytotoxicity studies

Vadhana¹,

Parveen²,

Ushadevi³

et al. 2019

Acta Crystallogr C

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A new set of differently hydrated barium and strontium squarates, namely poly[[triaqua(μ-1,2-dioxocyclobut-3-ene-1,2-diolato)barium] monohydrate], {[Ba(C4O4)(H2O)3]·H2O} n (1), poly[[diaqua(μ-1,2-dioxocyclobut-3-ene-1,2-diolato)strontium] monohydrate], {[Sr(C4O4)(H2O)2]·H2O} n (2), and poly[[triaqua(μ-1,2-dioxocyclobut-3-ene-1,2-diolato)barium/strontium(0.85/0.15)] monohydrate], {[Ba0.85Sr0.15(C4O4)(H2O)3]·H2O} n (3), is reported. The study of their crystal structures indicates that all the complexes crystallize in the triclinic space group P\overline{1}. Complexes 1 and 3 have a rare combination of squarate units coordinated through monodentate O atoms to two different metal atoms and through two bidentate O atoms to three different metal atoms. Furthermore, they have three coordinated water molecules to give a coordination number of nine. The squarate ligands in complex 2 exhibit two different coordination modes: (i) monodentate O atoms coordinated to four different Sr atoms and (ii) two monodentate O atoms coordinated to two different metal atoms with the other two O atoms bidentate to four different Sr atoms. All the compounds decompose to give the respective carbonates when heated to 800 °C, as evidenced by thermogravimetry/differential thermal analysis (TG-DTA), which are clusters of nanoparticles. Complexes 1 and 3 show additional endothermic peaks at 811 and 820 °C, respectively, indicating the phase transition of BaCO3 from an orthorhombic (α-Pmcn) to a trigonal phase (β-R3m). All three complexes have significant DNA-binding constants, ranging from 2.45 × 104 to 9.41 × 104 M −1 against EB-CT (ethidium bromide–calf thymus) DNA and protein binding constants ranging from 1.1 × 105 to 8.6 × 105 with bovine serum albumin. The in vitro cytotoxicity of the complexes is indicated by the IC50 values, which range from 128.8 to 261.3 µg ml−1. Complex 3 shows better BSA binding, antioxidant activity against the DPPH radical and cytotoxicity than complexes 1 and 2.

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Section: Introductionmentioning

confidence: 99%