Synthesis and Structural Characterization of ... - Jacobs University

Chapter 3
Unpublished Results
lanthanide-containing derivatives of the As 2 W 19 which have been synthesized in mildly acidic
aqueous media and structurally characterized by single-crystal X-ray. The monoytterbium(III)-containing
[Yb(H 2 O) 2 K(H 2 O) 2 As 2 W 19 O 67 (H 2 O)] 10−
which was formed by
reaction of Yb 3+ with the potassium salt of As 2 W 19 , while the di-lanthanum(III) derivative
[La 2 (H 2 O) 6 As 2 W 19 O 67 (H 2 O)] 8− was formed by reaction of La 3+ with the sodium salt of the
trilacunary precursor [B-α-AsW 9 O 33 ] 9− (AsW 9 ). 10
It can be noticed that extended studies of Sb 2 W 22 or Sb 2 W 20 M 2 are still limited. We have
decided to continue our investigation of the reactivity of lanthanide ions containing atoms
with lone pairs of electrons lacunary POM precursors, especially the SbW 9 and Sb 2 W 22 . This
work has resulted in the synthesis and structural characterization of six lanthanide-containing
tungstoantimonates(III) reported herein. In this work, ‘Ln’ will be used to designate
lanthanides and yttrium since the ionic radius of Y 3+ falls within the range of lanthanides.
3.B.2.2. Synthesis
The precursors Na 9 [B-α-SbW 9 O 33 ]·19.5H 2 O and Na 12 [Sb 2 W 22 O 74 (OH) 2 ] used for the
synthesis of the reported species were synthesized according to the published procedures by
Krebs. 5
Na 10 [Yb(H 2 O) 3 Sb 2 W 21 O 72 (OH)]·41H 2 O (Na-15)
0.068 g (0.175 mmol) of YbCl 3·6H 2 O was added to 20 mL 1M NaCl (aq) with stirring followed
by addition of 0.50 g (0.175 mmol) of Na 9 [B-α-SbW 9 O 33 ]·19.5H 2 O, and then the pH was
adjusted to 3 with 4M HCl. The solution was stirred at 50 ˚C for 30 min, allowed to cool to
room temperature. The filtrate was kept in an open vial for crystallization. After about three
weeks colorless crystals were obtained, which were filtered off and air dried (yield 0.15 g,
27 %). IR for Na-15 showed metal-oxygen stretches at 953(s), 874(sh), 840(m), 806(s),
758(m), 660(m), 525(w), 517(w), 472(w), 459(w), 431(w), 417(w) cm -1 (see Figure 3.27).
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