title: Gallium(III)-Containing, Sandwich-Type Heteropolytungstates: Synthesis, Solution Characterization, and Hydrolytic Studies toward Phosphoester and Phosphoanhydride Bond Cleavage.
abstract: The gallium(III)-containing heteropolytungstates [Ga4(H2O)10(β-XW9O33)2](6-) (X = As(III), 1; Sb(III), 2) were synthesized in aqueous acidic medium by reaction of Ga(3+) ions with the trilacunary, lone-pair-containing [XW9O33](9-). Polyanions 1 and 2 are isostructural and crystallized as the hydrated sodium salts Na6[Ga4(H2O)10(β-AsW9O33)2]·28H2O (Na-1) and Na6[Ga4(H2O)10(β-SbW9O33)2]·30H2O (Na-2) in the monoclinic space group P21/c, with unit cell parameters a = 16.0218(12) Å, b = 15.2044(10) Å, c = 20.0821(12) Å, and β = 95.82(0)°, as well as a = 16.0912(5) Å, b = 15.2178(5) Å, c = 20.1047(5) Å, and β = 96.2(0)°, respectively. The corresponding tellurium(IV) derivative [Ga4(H2O)10(β-TeW9O33)2](4-) (3) was also prepared, by direct reaction of sodium tungstate, tellurium(IV) oxide, and gallium nitrate. Polyanion 3 crystallized as the mixed rubidium/sodium salt Rb2Na2[Ga4(H2O)10(β-TeW9O33)2]·28H2O (RbNa-3) in the triclinic space group P1̅ with unit cell parameters a = 12.5629(15) Å, b = 13.2208(18) Å, c = 15.474(2) Å, α = 80.52(1)°, β = 84.37(1)°, and γ = 65.83(1)°. All polyanions 1-3 were characterized in the solid state by single-crystal XRD, FT-IR, TGA, and elemental analysis, and polyanion 2 was also characterized in solution by (183)W NMR and UV-vis spectroscopy. Polyanion 2 was used as a homogeneous catalyst toward adenosine triphosphate (ATP) and the DNA model substrate 4-nitrophenylphosphate, monitored by (1)H and (31)P NMR spectroscopy. The encapsulated gallium(III) centers in 2 promote the Lewis acidic synergistic activation of the hydrolysis of ATP and DNA model substrates at a higher rate in near-physiological conditions. A strong interaction of 2 with the P-O bond of ATP was evidenced by changes in chemical shift values and line broadening of the (31)P nucleus in ATP upon addition of the polyanion.
authors: Department of Life Sciences and Chemistry, Jacobs University , 28725 Bremen, Germany.
authors: Balamurugan
authors: B
authors: Kandasamy
authors: Department of Chemistry, KU Leuven , Celestijnenlaan 200F, B-3001, Heverlee, Belgium.
authors: Stef
authors: S
authors: Vanhaecht
authors: Department of Life Sciences and Chemistry, Jacobs University , 28725 Bremen, Germany.
authors: Fiona Marylyn
authors: FM
authors: Nkala
authors: Department of Chemistry, KU Leuven , Celestijnenlaan 200F, B-3001, Heverlee, Belgium.
authors: Tessa
authors: T
authors: Beelen
authors: Department of Life Sciences and Chemistry, Jacobs University , 28725 Bremen, Germany.|Department of Chemistry, Faculty of Sciences, University of Balamand , P.O. Box 100, Tripoli, Lebanon.
authors: Bassem S
authors: BS
authors: Bassil
authors: Department of Chemistry, KU Leuven , Celestijnenlaan 200F, B-3001, Heverlee, Belgium.
authors: Tatjana N
authors: TN
authors: Parac-Vogt
authors: Department of Life Sciences and Chemistry, Jacobs University , 28725 Bremen, Germany.
authors: Ulrich
authors: U
authors: Kortz
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D002384:Catalysis; D018360:Crystallography, X-Ray; D005708:Gallium / Q000737:chemistry*; D006868:Hydrolysis; D008958:Models, Molecular; D009596:Nitrophenols / Q000737:chemistry; D009943:Organophosphorus Compounds / Q000737:chemistry; D000071228:Polyelectrolytes; D011108:Polymers / Q000737:chemistry; D017973:Tungsten Compounds / Q000737:chemistry*
chemical_list: D000255:Adenosine Triphosphate; D005708:Gallium; D009596:Nitrophenols; D009943:Organophosphorus Compounds; D000071228:Polyelectrolytes; D011108:Polymers; D017973:Tungsten Compounds; C008644:nitrophenylphosphate; C025399:sodium tungstate(VI)