Mn III Compounds and Mixed Valence Complexes

The mixed valence complexes are similarly characterised but their spectral and magnetic behaviour is not as simple as the Mn(IIl) complexes. 

Use the oxalato-complex as soon as it is prepared. Dissolve in an oxalate solution at 15°C and run its visible spectrum in the range 370-600 nm. Measure its magnetic moment quickly and prepare a mull in Nujol and run its infrared spectrum. The compound is sensitive to moisture and light and is unstable on heating. 

Run the spectrum of [Mn(acac)3] in CHCI3 in the uv/visible region and its i.r. spectrum in a KBr disc. Measure its magnetic susceptibility and obtain results of elemental analysis. 

Similarly obtain results for the EDTA complex but record the spectrum using 1.4 x 10 M solution in acetic acid/acetate buffer at pH 2.S-4.0. Compare the absorption spectra with the spectra obtained earlier for the other Mn(III) compounds. 

Subject the mixed valence complexes to the same but use 0.05 M solution in aqueous bipyridyl buffer (pH4.5) or phenanthroline buffer. Compare the results for the two complexes. 

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