Synthesis of Tris(2,2'-bipyridine)ruthenium(II) Tetrafluoroborate
The procedure was modified by Jonathan Breitzer and George Lisensky
from John A. Broomhead and Charles G. Young, Inorg. Syn. 28, 338-340
(1990). The microwave procedure is from Chem. Letters (Japan)23 (1994) 2443-2446 or J. Electroanal. Chem.527 (2002) 33-40.
Grind about 3 grams of commercial RuCl3·3H2O
in a mortar and pestle and dry in a 100°C oven for a few hours. The
color will change from dark black to a dark brown.
Preparation of the Ru(II) complex
Option I: Dissolve 0.083 g (0.40 mmol) RuCl3·3H2O in 8 mL of water
in a 30-mL beaker equipped with a stirbar. Add 0.188 g (1.204 mmol) 2,2’-dipyridyl
and 0.44 mL of 6M NaH2PO2. Cover the beaker with a watch glass and reflux
for 30 minutes. Add water if necessary to maintain the volume.
Option II: Reflux a suspension of 0.083 g (0.40 mmol) RuCl3·3H2O, 0.188 g (1.204 mmol) 2,2’-dipyridyl
and 10 mL 1,2-ethanediol (also known as ethylene glycol) for 3 hours on a hotplate or for 5-15 minutes in a microwave oven with condenser. The diol serves as the reducing agent.
This method avoids the use of hypophosphorous acid which is a DEA List I restricted chemical.
Add 0.333 g of NaBF4 dissolved in 1.5 mL of water. Let
the solution cool to about room temperature and then cool in ice; crystals
Hypophosphorous acid, 50 wt % in water (Aldrich 21,490-6)
pH test paper
Mortar and pestle, small beaker, watch glass, suction flask, Hirsh funnel
Preparation of NaH2PO2 from H3PO2 (enough for 35 preparations)
Hypophosphorous acid is monoprotic (two of the hydrogens are attached
directly to phosphorus) with a pKa of 1.1. Use caution when handling.
Add 10 mL of 50 % H3PO2 into a beaker containing
6 mL of water and a stirbar.
Slowly add pellets of NaOH until the pH is
about 6-8. This will require about 3.9 g of NaOH. The final solution is
about 6 M in NaH2PO2.