Comparative Study of Vibrational Spectra of Two Bioactive Natural Products Lupeol and Lupenone Using MM/QM Method

Table 4

Comparison of the observed and calculated vibrational spectra of lupenone with (B3LYP/6-31G: PM3) methods.

B3LYP (Calc)	IR (Int.)	IR (Exp)	Vibrational assignments [P.E.D.]
602	7.414	580	β (C–C=O) + β (C–C–C)
793	3.127	712	β (C–C–H)
952	5.632	—	Rock (C–CH2) + Rock (C–CH3)
962	4.246	—	Rock CH2
1005	18.283	1014	β (C–C–H)
1040	7.213	—	Twist CH2
1056	9.850	1055 (sh)	Rock CH2
1123	4.486	—	Twist CH2
1131	5.153	1137	Twist CH2
1152	4.690	1155 (sh)	Rock CH2
1185	3.506	1180 (sh)	β (C–C–H)
1255	4.951	—	β (C–C–H)
1289	9.791	1285 (sh)	β (C–C–H)
1917	234.342	—	ν(C=O)
2734	4.850	—	ν(C–H)
2934	4.346	2941	ν(C–H)
2976	2.869	—	ν(C–H)

Abbreviations: ν: stretching; β: bending; S: scissoring; w: wagging; τ: torsion; sh: shoulder.