Experiment 5.1 Synthesis of Tris bidentate

EXPERIMENT 5.1 SYNTHESIS OF TRIS(BIDENTATE CHELATE)COBALT(III) COMPLEXES 

This excepts the synthesis of Ca[Co(ox)2(en)]2 4H20, which because of its challenging nature and time requirement, is level 5. 

The co-precipitate problems in the Ca[Co(ox)2(en)]2 4H20 synthesis occur because of the similar solubilities of the product and calcium oxalate under the given conditions. Calcium oxalate is an example of a sparingly soluble salt of a weak acid and provides a unique opportunity to examine solubility and pH. Sparingly soluble salts of weak acids can be dissolved in dilute solutions of strong acids. The protonation of oxalate(2—), equations (5.1) and (5.2), lowers the concentration of oxalate anions in solution solubility can therefore be controlled by pH. 

Safety warning Operations set off between the lines must be performed in a fume hood. 

Transfer your mixture to a beaker and evaporate the solution by suspending the beaker in a boiling water bath. Cease the evaporation process when a crust of product begins to form over the surface ( 7.5—10 ml). Add 7.5 ml of HClconc and 15 ml of ethanol to the mixture. 

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