March 28, 2024, 06:55:35 AM
Forum Rules: Read This Before Posting


Topic: Interpreting uv-vis spectra  (Read 703 times)

0 Members and 1 Guest are viewing this topic.

Offline Timu

  • Very New Member
  • *
  • Posts: 1
  • Mole Snacks: +0/-0
Interpreting uv-vis spectra
« on: March 11, 2021, 11:06:10 AM »
Hello everyone,
during my last lab course I synthesized cis-[RuCl2(DMSO)4]. Now I need to analyze it's uv-vis spectrum.
I was asked to assign electronic transitions to the absorption bands but since I haven't had my uv-vis lecture yet, I have trouble doing so. The spectrum is attached.

The bands are at 306 nm (ε = 357 L/mol*cm) and 360 nm (ε = 503 L/mol*cm) with CHCl3 as solvent.

I know that the d-configuration is low spin d6 and that three of the DMSO molecules bond via S (π-acceptor) and one via O (δ-donor), the Cl ligands are π-donors. So I think CT's in the form of π :rarrow: d and vice versa should be possible. I have read, though, that CT transitions have values of ε >1000.

d :rarrow: d transitions could occur as well but the example I have seen had lower ε values (below 200), so I am not sure whether they would be visible here.

A third option would be n :rarrow: π/δ transitions.

These are my thoughts, but I'm still not sure which transition fits which band since my ε values don't seem to fit except maybe for n :rarrow: π/δ transitions

Help would be much appreciated.

Sponsored Links