Preparation of Ag bipy

Weigh out 4.2 g silver nitrate and 7.8 g bipyridyl. Dissolve each in hot aqueous ethanol and mix the two hot solutions. Allow to cool and to crystallise. Collect the crystals by filtration under suction. Recrystallise from hot alcohol. Filter under suction while pressing between filter paper. Weigh your preparation and calculate the % yield based on Ag. 

Prepare a cold saturated solution of potassium persulphate and add an excess of the persulphate. Stir the silver(l) complex prepared above with the cold persulphate solution until the crystalline yellow needles are replaced by a red brown microcrystalline solid (this may take 1-2 hours). Wash thoroughly with cold water. Filter under suction as above. Store in a vacuum desiccator. 

The product can be analysed by titrating the iodine liberated when excess KI solution is added. 

Weigh out accurately about 0.2 g of your preparation, add excess of 10% KI solution and shake well until maximum colour of iodine is formed. Titrate using standardised 0.05 M thiosulphate solution as in Sec.7.3.3. Characterise the freshly prepared product by ir spectroscopy and by measuring its magnetic susceptibility (Sec.2.1.3). 

---