Preparation of the EDTA Complex

In the first step of the reaction, permanganate is reduced by ethanol to the dioxide. The freshly obtained dioxide reacts in the second stage widi the sodium EDTA salt which reacts forming the Mn(III) EDTA complex. 

Slowly add 12 g KMn04 to a mixture of 20 cm edianol and 80 cm water. Carefully shake the suspension and warm. After die vigorous reaction has subsided, warm intermittently to expel the excess ethanol and the aldehyde produced. Cool in an ice bath and add, with continuous stirring, a slurry of 23 g disodium EDTA in glacial acetic acid and allow to warm to room temperature. Filter off on a sinter any manganese dioxide and add to the cherry red filtrate an equal volume of cold edianol and cool in an ice bath for 1 hour and then filter the ciystals produced under suction. Wash with 3 x 30 cm  

Weigh out accurately about O.S g of your preparation, dissolve in known excess of 0.1 M ascorbic acid solution and back titrate the excess with standardised Mn solution as in Sec. 12.4.1. 

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The preparation of the edta complexes K[Ir(HY)Cl],2H20 and K[Ir(H2Y)Cl2] has been reported, together with polarographic and conductivity studies. Their i.r. spectra confirm the presence of both free and co-ordinated carboxylate groups. Investigations of piperidine-stabilized hydrido Ir complexes continue with the synthesis of the yellow species [HIr(pip)X2] (X = NCO, NCS, and NCSe) ... 

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