Chapter 4 - Jacobs University

Chapter 7
Pt-containing Polyoxometalate
7.2 Synthesis
Na 5 [H 2 PtV 9 O 28 ]·21H 2 O (5a) : H 2 [Pt(OH) 6 ] (0.20 g, 0.67 mmol; synthesized according to
reference 15) was dissolved in aqueous NaOH solution at pH 11 (10 mL), followed by addition
of a solution prepared by dissolving NaVO 3 (0.73 g, 6.0 mmol) in H 2 O (20 mL). This combined
solution was heated in a water bath for 30 minutes, allowed to cool to room temperature, and
then the pH was adjusted to 5.3 with 3M nitric acid. The volume of the solution was reduced to
about 15 mL in a water bath. After a day, very stable, red-brown, hexagonal-prismatic crystals of
5a formed, which were isolated by filtration and then dried in air. Yield: 0.65 g (61%). IR for 5a:
988 (s), 976 (s), 856 (s), 750 (s), 658 (w), 591 (sh), 527 (m), 531 (w), 519 (w) cm -1 . Elemental
analysis (%) calcd for 1a: Na 7.2, V28.7, Pt 12.2; found: Na 6.9, V28.9, Pt 12.0.
65
60
55
50
%Transmittance
45
40
35
30
648
846
25
431
419
20
988
976
750
591
527
1300
1200
1100
1000
900
800
Wavenumbers (cm-1)
700
600
500
Figure 7.1 FT-IR spectrum of 5a.
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