Tris 2,2-bipyridine ruthenium II dichloride Hexahydrate

Submitted by JOHN A. BROOMHEAD and CHARLES G. YOUNG Checked by PAM HOODt 

Samples of RuCl3 rH20 may contain Ru(IV), various oxo-and hydroxychloro-complexes, and nitrosyl species. Also, considerable variation in reaction times and product distribution may accompany the use of samples from different sources.4 In this synthesis, consistently high yields of [Ru(bipy)3]Cl2 can be obtained if the RuC13 xH20 is oven treated prior to use. 

Commercial RuC13-xH20 is dried in an oven at 120° for 3 hours. It is then finely ground in a mortar and returned to the oven for a further 1 hour prior to use. It is convenient to store the dried RuC13 at this temperature. 

During reflux, the initial green solution changes to brown and finally orange. It is filtered to remove traces of undissolved material and potassium chloride (12.6 g) added to the filtrate to precipitate the crude product. The solution and solid are then heated at the boil to give a deep-red solution which on cooling to room temperature yields beautiful, red platelike crystals. These are filtered off, washed with ice-cold 10% aqueous acetone (2X5 mL) and acetone (30 mL), and air dried. The yield is 1.15 g (80%). The product may be recrystallized from boiling water ( 2.8 mL/g) and then air dried. 

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