C5855
Vibrační spektroskopie

Jan Novotný 2019

Intro
Compare wavenumbers for following vibration modes:
1.

Stretch C=N vs Stretch C-N Stretch C-H vs Stretch C-C Bend N-H vs Stretch N-H

2.

3.

Calculate number of normal modes of CO2 and select IR active ones.

Campbell textbook
In CO2 IR spectra, two (degenerate) bending vibrations are observed at 667 cm −1 and one asymmetric stretch is observed at 2349 cm −1 . A further (symmetric stretch) band is predicted at 1537 cm −1 but is not observed. Comment on these results.

Campbell textbook
When CO2 binds to carbonic anhydrase, a zinc-containing enzyme that catalyzes CO2 hydration, no change in the 2349 cm−1 asymmetric stretch band was observed. Comment on this result.
Unaffected bond force constant indicated that CO 2 is bound noncovalently into catalytic site. Contrarily, Zn coordinates and polarizes H 2O molecule which is activated for hydration.

Campbell textbook
Alanine has a band at 1308 cm−1 , assigned to –CH deformation. In deuteroalanine this band is absent, but a new band appears at 960 cm−1 . Why?

Campbell textbook

Campbell textbook
Applications of resonance Raman techniques are limited by chromophore fluorescence”. Give an explanation for this statement.
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