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

Table 2

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

Assignment	Nitrobarbituric (cm^−1)	Cocrystal (cm^−1)	Cinchonine (cm^−1)	Assignment
Carbonyl in-plane bending mode	379	357
Carbonyl out-of-plane bending mode	625	609
Carbonyl out-of-plane bending mode	695	681
N–H out-of-plane bending mode	846	838
C–N stretching mode	1150	1137
C–N deformation mode	1255	1248
		1361	1360	Nonprotonated quinuclidine mode
		1572	1566	Nonprotonated quinoline mode