Table 4.

Values of the selected vibrations in the calculated IR and Raman spectra (Figure 4) for the optimized structures of the keto-oxime, keto-hydroxylamine, and hydroxyl-oxime tautomers of molnupiravir, obtained by using the DFT/B3LYP/6-311++G(d,p) method.

Molecular Vibration 1	Frequency (cm−1)	IR Intensity (KM∙mol−1)	Raman Activity (Å4∙amu−1)	Force Constant, k (mDyne A−1)
keto-oxime
νO5–H4	3856	189.04	220.68	9.3559
νO2–H3	3754	73.43	60.22	8.8462
νO3–H2	3629	417.06	96.23	8.2735
νNH	3605	109.93	48.16	8.2416
νs(C6–H9 + C7–H10)	3261	12.72	74.49	6.8628
νas(C6–H9 + C7–H10)	3237	6.62	66.59	6.7326
νC13–H14	3120	20.70	48.34	6.3159
νasH14–C12–H15	3106	15.07	37.91	6.2675
νC1–H5	3102	21.15	84.32	6.1803
νC13–H18	3099	25.87	71.32	6.2376
νasH15–C12–H16	3095	29.03	43.98	6.2194
νasH11–C9–H12 + νC1–H5	3077	13.81	48.81	6.1665
νC11–H13	3058	14.12	130.10	5.9645
νC2–H6	3046	37.37	58.52	5.9362
νC4–H8 + νC2–H6	3043	22.81	157.47	5.9235
νs(C13–H17 + C13–H18 + C13–H19)	3037	22.14	204.18	5.6303
νs(C12–H14 + C12–H15 + C12–H16)	3031	25.20	121.28	5.6016
νs(C9–H11 + C9–H12)	3027	19.80	43.60	5.7009
νC3–H7	2994	23.23	49.13	5.7226
νC10=O7	1814	367.75	20.51	22.8748
νC5=O4 + βN2–H3 + βO3–H2	1733	836.72	22.71	11.9387
νC8=N3 + νC5=O4 + νC6=C7 +βO5–H4 + βN2–H3 + βC6–H9 + βC7–H10	1714	140.42	371.53	13.9766
keto-hydroxylamine
νO2–H1	3745	76.60	59.88	8.8028
νN3–H3	3619	108.95	137.56	8.3276
νO3–H2	3569	526.21	126.65	8.0039
νO5–H4	3512	85.58	129.66	7.7383
νs(C6–H9 + C7–H10)	3244	9.42	77.27	6.7877
νas(C6–H9 + C7–H10)	3216	0.59	82.40	6.6483
νC13–H17 + νC13–H18 + νC13–H19	3120	19.99	48.02	6.3164
νC12–H14 + νC12–H15 + νC12–H16	3106	15.40	37.56	6.2662
νC1–H5	3101	20.69	86.39	6.1751
νasH18–C13–H19)	3099	26.15	71.95	6.2365
νasH15–C12–H16)	3095	28.63	44.13	6.2181
νasH11–C9–H12 + νC1–H5	3075	14.97	46.70	6.1604
νC11–H13	3056	13.35	110.25	5.9559
νC2–H6	3055	21.17	105.53	5.9716
νC4–H8	3041	33.92	129.47	5.9150
νs(C13–H17 + C13–H18 + C13–H19)	3037	22.96	204.79	5.6307
νs(C12–H14 + C12–H15 + C12–H16)	3031	23.47	110.87	5.5975
νsH11–C9–H12	3025	21.21	50.87	5.6943
νC3–H7	2987	27.06	45.99	5.6959
νC10=O7	1815	365.00	19.83	22.8983
νC5=O4 + βO5–H4 + βO3–H2 + βC6–H9	1715	785.23	33.24	17.0337
νC8=N3 + νC5=O4 + νC6=C7 +βC6–H9 + βC7–H10 + βC2–H6	1663	291.45	25.55	10.4411
βN3–H3 + βO5–H4	1591	20.24	20.25	2.7871
hydroxyl-oxime
νO2–H1 + νO3–H2 + νO4–H3	3782	94.84	36.15	8.9787
νO2–H1 + νO4–H3	3774	27.16	36.51	8.9377
νO5–H4	3615	16.28	90.73	8.2026
νC6–H9	3273	9.92	75.23	6.9078
νC7–H10	3222	2.37	85.81	6.6768
νC13–H17 + νC13–H18 + νC13–H19	3121	19.94	49.24	6.3195
νC12–H14 + νC12–H15 + νC12–H16	3106	14.34	42.24	6.2714
νasH18–C13–H19	3100	23.66	67.74	6.2426
νC1–H5 + νasH11–C9–H12	3099	22.56	82.80	6.1714
νC12–H14 + νC12–H15 + νC12–H16	3095	30.72	47.70	6.2155
νC1–H5 + νasH11–C9–H12	3077	12.97	50.18	6.1565
νC2–H6	3061	20.82	56.13	5.9950
νC11–H13	3056	14.50	140.64	5.9601
νC4–H8	3047	29.86	139.46	5.9408
ν(C13–H17 + C13–H18 + C13–H19)	3038	21.16	199.10	5.6333
ν(C12–H14 + C12–H15 + C12–H16)	3031	24.44	122.92	5.5991
νsH11–C9–H12	3025	23.18	61.34	5.7005
νC3–H7	3006	17.27	35.96	5.7667
νC10=O7	1817	363.72	20.82	22.9946
νC5=N2 + νC6=C7 + βO4–H3 + βC6–H9 + βC7–H10	1718	556.37	146.50	12.9824
νC8=N3 + νC5=N2 + νC6=C7 +βO4–H3 + βC7–H10	1658	71.05	288.48	13.6289
νC8=N3 + νC5=N2 + νC6=C7 +βO4–H3 + βO5–H4 + βC6–H9 + βC7–H10	1609	85.65	63.89	13.3853

¹ ν—stretching, ν_s—symmetric stretching, ν_as—antisymmetric stretching, β—bending.