Synthesis and Structural Characterization of ... - Jacobs University

Chapter 5
Published Results
H 2 O) 2 K(Ge 2 W 18 O 66 )] 13– . 26
Recently Wang’s group reported [Mn 2 (H 2 O) 8 Mn 4 (H 2 O) 2 (B-α-
GeW 9 O 34 ) 2 ] 8– which is composed of Weakley-type [Mn 4 (H 2 O) 2 (B-α-GeW 9 O 34 ) 2 ] 12– units
connected via two Mn 2+ ions forming a 1D chain. 27a Yamase et al. reported the synthesis of
[Cu 4 (GeW 9 O 34 ) 2 ] 12– showing a Cu 8+ 4 tetragon α-conjugated to two [B-α-GeW 9 O 34 ] 10− Keggin
moieties. 27b
A few years ago, we reported the synthesis and structural characterization of the
dilacunary decatungstogermanate [γ-GeW 10 O 36 ] 8– . 28 Since then, we have been exploring its
reactivity with various transition metal and rare earths ions, organometallic groups, and other
electrophiles. Some of these results have already been published. 19,21 Here, we report on the
synthesis and structural characterization of dimeric copper-, cobalt-, and manganesecontaining
tungstogermanates.
5.B.2. Synthesis
The dilacunary precursor K 8 [γ-GeW 10 O 36 ] was synthesized according to the published
procedure and its purity was confirmed by infrared spectroscopy. 28
K 12 [Cu 3 (H 2 O)(B-β-GeW 9 O 33 (OH))(B-β-GeW 8 O 30 (OH))]·31H 2 O (K-29)
A 0.05 g (0.28 mmol) sample of CuCl 2·2H 2 O was dissolved in 20 mL of 1M potassium
acetate buffer at pH 4.8, followed by the addition of 0.50 g (0.17 mmol) of K 8 [γ-
GeW 10 O 36 ]·6H 2 O. Then, the solution was stirred and heated to 50 °C for 30 minutes. The
solution was allowed to cool to room temperature and then filtered. Slow evaporation of the
solvent at room temperature for about one day led to the formation of light-green crystals
suitable for X-ray diffraction. These crystals were isolated and air-dried (yield 0.08 g, 14 %).
IR for K-29: 940 (m), 900 (m), 872 (m), 815 (sh), 790 (sh), 766 (s), 713 (s), 503 (w), 449 (w),
430 (sh) cm -1 (see Figure 5.14). Anal. Calcd (%) for K-29: K, 8.5; W, 56.3; Cu, 3.4; Ge, 2.6.
Found (%): K, 8.7; W, 55.2; Cu, 3.5; Ge, 2.7.
200