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

Table 6

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

Assignment	Nitrobarbituric (cm^−1)	Cocrystal (cm^−1)	Quinine (cm^−1)	Assignment
Carbonyl in-plane bending mode	379	368
Carbonyl out-of-plane bending mode	625	610
Carbonyl out-of-plane bending mode	695	679
N–H out-of-plane bending mode	846	834
C–N stretching mode	1150	1125
C–N deformation mode	1255	1242
		1359	1366	Nonprotonated quinuclidine mode
		1586	1585	Nonprotonated quinoline mode