Research Article

Spectroscopic Characterization of Omeprazole and Its Salts

Table 2

Peak frequencies of bands in infrared and Raman spectrum of OMP.

IR (cm−1)Raman (cm−1)Assignation

~3070 (shift)3076CH stretching (BI, P)
30573055CH stretching (BI, P)
3016CH stretching (BI, P)
29842981CH3 (M) stretching asymmetric
2972~2968 (sh)CH3 (M) stretching asymmetric
29442954CH3 (M) stretching asymmetric
~2930CoveredNH stretching vibration
29042915CH3 stretching asymmetric
28542857CH3 (M) stretching symmetric
28352837CH3 stretching symmetric
16291629QS (P), CH deformation, CC stretching (P, BI)
15871588CH + NH deformation, CC stretching (BI)
15681569QS (P), CH deformation, CC stretching (P, BI)
15121514CH + NH deformation (BI)
1470 (sh)1477SCS (P), CH (B), NH deformation, N3C2 stretching
14621460CH3 deformation (M), NH + CH deformation (BI)
14281432SCS (P), CH3 deformation symmetric
14101412NH + CH deformation (BI), CH deformation (P)
13561356NH + C4H + C5H deformation (BI)
13121314CH deformation, R-O-CH3 stretching
1293R-O-CH3 stretching
12731273NH + CH deformation symmetric (BI)
12531255NH + CH deformation symmetric (BI)
12311232NH + CH deformation asymmetric (BI)
12061203NH + CH deformation symmetric (BI)
11881190NH + CH deformation symmetric (BI)
11601160CH deformation asymmetric
11131113CH deformation asymmetric
10771076NH deformation (BI), CH3 (M)
10141009S=O stretching vibration
967963CH deformation (BI)
885886CH wagging
835842CH3 rocking of methoxy group
822823QIPB (P)
810790CH3 rocking ip
787CH3 rocking ip
759762CH wagging (IM)
732733CH wagging (B)
667653NH wagging (BI)
631635S-C stretching sulfoxide chain
621620QIPB (P), ring deformation
582582CH + NH wagging (BI)
546546 (sh)oop ring deformation
535538oop ring deformation
518519oop ring deformation
502504oop ring deformation
478479oop ring deformation
444R-O-CH3 deformation (M)
429Ring deformation (BI)
382QOOPB (P)
327CH wagging asymmetric (BI)
254R-O-CH3 deformation (M)
212CH wagging
142Phonon vibration
124Phonon vibration
104Phonon vibration
87Phonon vibration
72Phonon vibration
66Phonon vibration

BI: benzimidazole; P: pyridine; M: methoxy group; IM: imidazole; QS: quadrant stretch; SCS: semi-circle stretch; oop: out-of-plane; ip: in-plane; QIPB: quadrant in-plane bend; QOOPB: quadrant out-of-plane bend.