Synthesizing and Investigating Cobalt Complexes: UV-Vis and Structure-Property Relationships

Post-Lab Activity

Use the table below to help you answer questions 27 and 28:


Complex

Δ value (cm-1)*

Your Estimated  Δ value (cm-1)

Cyanide complex

33909

 

Glycine complex

20266

 

Oxalate complex

18153

 

Phenanthroline complex

26198

 

Water complex

18406

 

*From Riordan et al. Chem. Educator. 2005, 10, 115-119.
27. Above are calculated Δ values using Tanabe-Sugano diagrams reported for the Cobalt (III) complex ions studied by Riordan et al. Copy your estimated Δ values (frequencies in wavenumbers) into the table and compare your estimated Δ values to the literature values. As you compare, note the relative magnitudes of the values as well as their rank order from lowest to highest.

28. Based on your answers to questions 26 and 27, explain why there are differences (if any) among all four spectrochemical series (UV-vis, eyes as detectors, and two from the literature).

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