Chapter 4 - Jacobs University

Chapter 5
Organoruthenium POM
5.2 Synthesis
Preparation of K 12 Li 15 [{K(H 2 O)} 3 {Ru(p-cymene)(H 2 O)} 4 P 8 W 49 O 186 (H 2 O) 2 ]·87H 2 O (3a):
a sample of K 28 Li 5 [H 7 P 8 W 48 O 184 ]·92H 2 O (0.37 g, 0.025 mmol) was dissolved in aqueous 1M
LiOAc/CH 3 COOH buffer solution (20mL) at pH 6.0, followed by addition of [Ru(pcymene)Cl
2 ] 2 (0.17 g, 0.28 mmol). Then the solution was heated to 80 ºC for 1h and filtered hot.
After cooling to room temperature 1M KCl solution (5 mL) was added. The filtrate was allowed
to evaporate in an open beaker at room temperature, resulting in a red-brown crystalline product
after about two weeks. Yield: 0.19 g (49 %). IR for 3a: 1136(m), 1083(m), 1015(w), 974(sh),
925(s), 799(s), 628(s), 574(w), 528(w), 461(w), 424(w) cm -1 . Anal. found: C, 3.16; H, 1.65; P,
1.51; K, 3.61; Li, 0.79; W, 58.7; Ru, 2.51; calc for 3a: C, 3.08; H, 1.61; P, 1.59; K, 3.76; Li,
0.67; W, 57.8; Ru, 2.59. Thermal decomposition of 3a (Figigure 5.2) starts at room temperature
and shows a smooth dehydration step ending in a plateau at about 280 °C. This step involves the
release of ~87 water molecules [found: 10.1; calc: 10.0]. Above this temperature, we observe a
slightly less regular weight loss with 3 steps up to about 690 °C. It appears that in this domain
the slightly stronger bonded water ligands (e.g. K1···OH 2 , K6···OH 2 , Ru-OH 2 and W-OH 2 ) are
lost (probably in this sequence) together with the four p-cymene groups [found: 4.29; calc: 4.48].
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