Infrared Spectrum of Caffeine and its Hydrochloride Dihydrate

A photothermal Mach-Zehnder interferometer for measuring caffeine and proteins in aqueous solutions using external cavity quantum cascade lasers

“…1660 and 1710 cm -1 corresponding to C=O absorption bands of caffeine ( Figure 4B). 19 As expected, the PTI amplitude decreases with increasing modulation frequency, because under these experimental conditions the non-optical response cannot take place to its full extent. In addition, the dependence of the PTI amplitude on the modulation frequency was investigated for different media.…”

“…1660 and 1710 cm -1 , characteristic for C=O absorption bands of caffeine. 19 For comparison, a FTIR spectrum of caffeine in ethanol is shown in Figure 6B. Moreover, PTI amplitudes were recorded at different caffeine concentrations at a modulation frequency of 230 Hz ( Figure 7A).…”

Computationally‐Assisted Approach to the Vibrational Spectra of Molecular Crystals: Study of Hydrogen‐Bonding and Pseudo‐Polymorphism

“…In this context, the analysis of the vibrational spectra (Raman and FTIR), in particular of CA and TP, has aroused considerable interest. [6,[16][17][18][19][20][21][22] However, to the best of our knowledge, no complete vibrational assignment has been attempted yet and the complete and reliable assignment of the vibrational spectra of these compounds is naturally justified. Very recently some works showed the vibrational spectra of CA, TP, and TB, [6,12,[19][20][21]23] but, unfortunately, including incomplete, questionable and even misleading assignments, as reported previously by some of us.…”

DFT study of the physicochemical characteristics and spectral behavior of new 8‐substituted 1,3,7‐trimethylxanthines

“…The C 2 O group in caffeine fragment is expected to be more basic than C 6 O group, as the first is joined to two NCH 3 groups, while the second–to one NCH 3 group and to sp 2 carbon atom of the neighbor double bond. It must also be considered, that like in guanine, the stretching vibration of C 6 O group is probably coupled with the νCC mode 24…”