Synthesis and Structural Characterization of the 28‐Isopolytungstate Fragment [H 2 W 28 O 95 ] 20– Stabilized by Two External Lanthanide Ions [Ln 2 (H 2 O) 10 W 28 O 93 (OH) 2 ] 14–

Autor: Amal H. Ismail, Ulrich Kortz, Bassem S. Bassil, Andreas Suchopar
Rok vydání: 2009
Předmět:
Zdroj: European Journal of Inorganic Chemistry. 2009:5247-5252
ISSN: 1099-0682
1434-1948
Popis: The V-shaped polyanions [Ln 2 (H 2 O) 10 W 28 O 93 (OH) 2 ] 14- [Ln = Sm (1), and Eu (2)] have been synthesized by reaction of Ln 3+ and WO 4 2- in aqueous acidic medium. The sodium salt of 1 and the mixed sodium-europium salt of 2 have been characterized in the solid state by FTIR, single-crystal XRD, thermogravimetric analysis (TGA), and elemental analysis. Single-crystal X-ray analyses were carried out on P4a 14 [SM 2 (H 2 O) 10 -W 28 O 93 (OH) 2 ]·40H 2 O (Na-1) which crystallizes in the triclinic system, space group P1, a = 14.8727(6) A, b = 21.7762(11) A, c = 23.5751(10) A, a = 89.175(2)°, β = 86.430(2)°, γ = 75.364(2)°, and Z = 2 and on Na 8 Eu 2 [Eu 2 (H 2 O) 10 W 28 O 93 (OHh]. 47H 2 0 (NaEu-2) which crystallizes in the monoclinic system, space group P2 1 /n, a = 25.3862(11) A, b = 14.6364(5) A, c = 40.3264(16) A, β = 96.107(3)°, and Z = 4. The polyanions 1 and 2 consist of a novel isopolyanion unit [H 2 W 28 O 95 ] 20- and two {Ln(H 2 O) n } 3+ supporting groups. The {W 28 } cluster coordinates to the two Ln 3+ ions and acts as a tri- and tetradentate ligand for the two lanthanide ions. The {W 28 } cluster consists of two undecatungstate {W 11 } fragments and a hexatungstate fragment {W 6 }. Furthermore, in the solid state, one {W 28 } fragment is connected to another {W 28 ] via lanthanide-oxo bridges forming a {W 56 } aggregate ([Ln 2 (H 2 O) 10 W 28 O 93 -(OH) 2 ] 14- ) 2 . It was also possible to synthesize other lanthanide derivatives of the {W 28 } cluster (Ln = La, Ce, Pr, Nd, and Gd) as determined by FTIR and preliminary single-crystal X-ray diffraction data.
Databáze: OpenAIRE
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