[eb51111]

I have obtained the following CV's from [Ru(bpy)₃] and Ru(bpy)₂Cl₂, (attached). I have calculated the half wave potentials (E_1/2) as 1.36 V and 0.38 V for the respective complexes.

I have also measured UV-Vis of both complexes - with peak absorbances at 452 nm and 378 nm respectively. I've calculated the HOMO-LUMO gap from this data for Ru(bpy)3 to be 2.74 eV.

Is there a way to calculate/confirm the HOMO-LUMO gap from cyclic voltammetry - using the Nernst equation for example - as I'm relatively new to this area?

Any help much appreciated!

Thank you.

[Corribus]

To calculate the HOMO-LUMO gap from electrochemistry, you need both the first oxidation and first reduction potentials. Then you just subtract the one from the other. You only have half of that information from your CV. You need to scan in the other direction.

Note that the energy gaps determined from electrochemistry and electronic spectroscopy do not always have good agreement. Off the top of my head I don't know if that's the case for this complex but don't be surprised if it is.