Greetings,
I do some research regarding molecule structure embed with triazole moiety, there is two emission peaks observed in flurorescence. How could these observation happened from triazole ?
Thank you in advance for helping.
Make sure that one of the 2 bands is not just the Raman scattering signal from the solvent.
Some compounds, if they are concentrated enough, can self-associate to form oligomers, and this can result in an excimer fluorescence peak in the emission spectrum in addition to the monomer fluorescence peak. Pyrene is a good example of a a compound that does this.
Yes, a molecule can emit at multiple wavelengths at one excitation wavelength.
I can't give you a precise reason for your molecule without knowing its exact structure, but usual reasons are vibrational states of the molecule (usually the case when the emission peaks are fairly close together) or isomeric forms of your compound co-existing at the conditions of your measurement.
To add to Simons answer: you should first check if the two maxima are different emission bands or just two maxima of the same emission band - we call the latter vibrational progression.
This check is easy: vary the excitation frequency. If the distance is always the same between the two maxima (importantly; in cm-1, not in nm !!!) then they are very probably one band with vibrational structuring (vibrational progression). You can also take the distance of the two maxima (in cm-1) and compare this number with an IR spectrum. You should find a strong IR band around this energy (in cm-1).
If these are two emission bands, you can check this also by varying the excitation wavelength. If the two maxima vary in energy AND intensity, they are two bands.
Make sure that one of the 2 bands is not just the Raman scattering signal from the solvent.
Some compounds, if they are concentrated enough, can self-associate to form oligomers, and this can result in an excimer fluorescence peak in the emission spectrum in addition to the monomer fluorescence peak. Pyrene is a good example of a a compound that does this.
Collecting an excitation scan of the two different emission bands will tell you whether both bands are the result of the same absorption (both excitation scans will match each other and most likely match your absorption spectrum) or whether the two bands are due to different species or excited states (the two excitation scans will be different)
Simon Janich Axel Klein Adam B Shapiro Catherine E Mccusker . Yes, probably due to both n-to-pi* and pi-to-pi* transition from triazole i guess. In absorption spectra, there is excitation peaks overlapping from n-to-pi* and pi-to-pi*.
In a number of ways there may be more than one emission peaks; for instance n-to-pi* and pi-to-pi* transition, excited state processes like charge transfer, proton transfer, protonation, excimer formation and even environmental heterogeneity some time. Besides, ground state conformers may also be a cause. In your particular case what is the cause than needs to be delineated.
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