Chiral IR Spectroscopy

[snpd]

In my diploma thesis i stumbled upon a pretty special topic: chiral ir spectroscopy, but without looking at light polarization (like in VCD). I basically created a multivariate model (with PLS) with infrared spectroscopy for the determination of D-Tyrosine and L-Tyrosin content in DL-Tyrosine powders based on the effect of changes in absorption wavenumbers of enantiomers. I found out about this phenomenon for amino acids through the application note of thermo fisher (assets.thermofisher .com/TFS-Assets/CAD/Application-Notes/AN₅₄₆₈₆-npi-summit-x-chemistry-app-note-en.pdf). I wanted to ask if anyone has experience in this field or can give more detailed information, as i couldn't really find any good literature about this topic (this effect is nowhere covered or mentioned). Even the cited literature in the application note doesn't give any further information than, that this effect is based on "crystal symmetry, geometric parameter distinctions, and hydrogen bonding". This gives some hints, but I'm missing further explanation.

I would be very grateful, if someone could help me

[onlookerterm]

In my diploma thesis i stumbled upon a pretty special topic: chiral ir spectroscopy, but without looking at light polarization (like in VCD). I basically created a multivariate model (with PLS) with infrared spectroscopy for the determination of D-Tyrosine and L-Tyrosin content in DL-Tyrosine powders based on the effect of changes in absorption wavenumbers of enantiomers. I found out about this phenomenon for amino acids through the application note of thermo fisher (assets.thermofisher .com/TFS-Assets/CAD/Application-Notes/AN₅₄₆₈₆-npi-summit-x-chemistry-app-note-en.pdf). I wanted to ask if anyone has experience in this field or can give more detailed information, as i couldn't really find any good literature about this topic (this effect is nowhere covered or mentioned). Even the cited literature in the application note doesn't give any further information than, that this effect is based on "crystal symmetry, geometric parameter distinctions, and hydrogen bonding". This gives some hints, but I'm missing further explanation.

I would be very grateful, if someone could help me

The shifts in IR absorption you're observing likely stem from solid-state effects, like crystal packing and hydrogen bonding, which can differ between enantiomers. This phenomenon is not widely discussed, but you might find useful insights in solid-state NMR/IR studies or research on pharmaceutical polymorphism. Journals like Vibrational Spectroscopy could also have related papers.

[Sophia2005]

In my diploma thesis i stumbled upon a pretty special topic: chiral ir spectroscopy, but without looking at light polarization (like in VCD). I basically created a multivariate model (with PLS) with infrared spectroscopy for the determination of D-Tyrosine and L-Tyrosin content in DL-Tyrosine powders based on the effect of changes in absorption wavenumbers of enantiomers. I found out about this phenomenon for amino acids through the application note of thermo fisher (assets.thermofisher .com/TFS-Assets/CAD/Application-Notes/AN₅₄₆₈₆-npi-summit-x-chemistry-app-note-en.pdf). I wanted to ask if anyone has experience in this field or can give more detailed information, as i couldn't really find any good literature about this topic (this effect is nowhere covered or mentioned). Even the cited literature in the application note doesn't give any further information than, that this effect is based on "crystal symmetry, geometric parameter distinctions, and hydrogen bonding". This gives some hints, but I'm missing further explanation.

I would be very grateful, if someone could help me

The shifts in IR absorption you're observing likely stem from solid-state effects, like crystal packing and hydrogen bonding, which can differ between enantiomers. This phenomenon is not widely discussed, but you might find useful insights in solid-state NMR/IR studies or research on pharmaceutical polymorphism. Journals like Vibrational Spectroscopy could also have related papers.

Have you tried comparing your IR results with Raman spectroscopy data to see if the enantiomeric differences also show up there, or is the effect limited only to IR in the solid state?

[irtubes]

For specialty chemical processing, techniques, methods, and formulations, you can also check more information from irtubes