Research Article

Vibrational Spectroscopic Study of the Cocrystal Products Formed by Cinchona Alkaloids with 5-Nitrobarbituric Acid

Table 4

Assignments of the major bands in the fingerprint region of the Raman spectra of 5-nitrobarbituric acid, cinchonidine, and their 1 : 1 cocrystal product.

AssignmentNitrobarbituric (cm−1)Cocrystal (cm−1)Cinchonidine (cm−1)Assignment

Carbonyl in-plane bending mode379373
Carbonyl out-of-plane bending mode625617
Carbonyl out-of-plane bending mode695681
N–H out-of-plane bending mode846843
C–N stretching mode11501132
C–N deformation mode12551252
13581359Nonprotonated quinuclidine mode
15911564Nonprotonated quinoline mode