Chapter 4 - Jacobs University

Chapter 9
Unpublished Results
9.3.5 Synthesis of K 10 [Hf 4 (OH) 6 (H 2 O) 4 (β-SiW 10 O 37 ) 2 ]·40H 2 O (24a)
A 0.294 g (0.1mmol) of K 10 [γ-SiW 10 O 36 ] was dissolved in 20 mL of 1M KOAc buffer solution
(pH 4.8), and then 0.128 g (0.4 mmol) of HfCl 4 was added. The solution was heated at 50 o C for
30 min and filtered hot. Then of 1M KCl (0.05 mL) was added to the solution which was allowed
to evaporate in an open vial at room temperature. Slow evaporation at room temperature led to
the appearance of white crystalline product after about one week. Evaporation was allowed to
continue until the solution level approached the solid product, which was filtered off and airdried.
Yield 0.183g (62%). IR : 1051(m), 995(w), 956(s), 899(m), 867(m), 778(vs), 665 (w),
537(w), 474(sh) cm -1 .
58
56
54
52
50
48
46
44
%Transmittance
42
40
38
36
34
32
30
28
26
24
22
20
1200
1100
1000
900
800
Wavenumbers (cm-1)
700
600
500
Figure 9.67 FTIR spectrum of 24a.
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