[StS]

I am trying to find out which would cause a greater field splitting (acac^- or ox) but I am having a hard time finding any explanation of the spectrochemical series. Generally acac^- is not listed in the series but I have found it to be approximate to water, but from there I don't know how to distinguish the two. I believe ox is a better pi donor but I am not sure. Anybody have an explanation?


I am also analyzing the uv/vis spectrum of Cr(acac)₃ and would greatly appreciate it if someone could link me to literature explaining the spectrum.

Thanks

[vex]

This is a trickier question than I thought it was at first glance!

Think about how each ligand binds to the metal center. Are they neutral, anionic, doubly anionic...? Would you classify one or both as a pi donor? If one or the other isn't a pi donor, what kind of ligand is it? If they are both pi donors, how can you rate their relative strength?

As for the uv-vis spectrum, I'd have to see it to help you totally analyze it, but you can generally get away with saying that any intense, sharp peaks are either ligand to metal or metal to ligand charge transfers, and that any broad, weak (especially for first-row metals) peaks are metal d-d transitions. It's possible that at high energy you can also get ligand-ligand transitions, most commonly pi-pi*.