Dear all,
We have recently “joined” the area of EPR spectroscopy and we have some questions regarding the spectrum analysis. I would appreciate it if anyone could provide us with valuable answers or literature references.
1) How do you make the choice of the ideal (optimum) spectrum of your sample (dissolved in DCM, C 10-3 M) and how do you verify that your data are correct?
2) Easyspin requires the introduction of the number of expected parameters. If for example, I have 3 Nitrogens in my structure, I expect to receive 3 hyperfine couplings. However, how do the substituents affect the number of the expected parameters? e.g., in the literature the “CF3” substituent gives an additional hyperfine coupling but not always; so what defines the additional hyperfine coupling?
Noting that the instrument we are using for the measures is the “Adani EPR spectrometer”
Thank you in advance.
Best wishes,
Styliana
Dear Styliana,
I presume you are talking about a radical (paramagnetic species) derived from an heterocyclic system.
EPR spectra are usually very complex. The hyperfine spliting depends on the number ans type of atoms with a magnetic moment different from zero (e.g. H=1/2, N=1). In your case, id the 3 N are magnetically equivalent your spectrum will be splitided in 5 line4s; if they are not equivalent i. 9. This spliting will be ,multiplied by the couplings wit hydrogen atoms (or with other ones with I not zero if present).
In a complex radical the spectra will be symmetrical (if in solution, at RT) with a huge number of lines. You have to measure the coupling constants and simulate the spectrum wit the appropriate software.
- Badges
- Science topic
- Similar topics
- Chemistry
- Organic Chemistry