Spectroscopic Investigations and DFT Calculations on 3-(Diacetylamino)-2-ethyl-3H-quinazolin-4-one

Table 2

Observed and calculated vibrational frequencies of title compound with 6-311++G(d,p).

Vibration number	Assignment (PED%)	⁢Observed frequencies		⁢Calculated frequencies in cm^−1
		FT-IR	Laser-Raman	B3LYP	M06-2X
	υCH (93) in ring 1	3083	3079	3078	3057
	υCH (98) in ring 1	3083	3079	3074	3052
	υCH (89) in ring 1	3083	3079	3063	3042
	υCH (94) in ring 1	3045	3079	3048	3028
	υCH (91) in asymm. str. CH3	3045	3079	3033	3025
	υCH (99) in asymm. str. CH3	3045	3079	3032	3024
	υCH (100) in asymm. str. CH3	3003	2993	3009	3006
	υCH (65) in asymm. str. CH3	3003	2993	3003	2988
	υCH (99) in asymm. str. CH3	3003	2993	2996	2987
	υCH (99) in asymm. str. CH3	3003	2993	2989	2977
	υCH (85) in symm. str. CH3	2949	2938	2943	2929
	υCH (92) in asymm. str. CH2	2934	2938	2939	2922
	υCH (99) in symm. str. CH3	2934	2938	2934	2916
	υCH (98) in symm. str. CH3	2934	2914	2928	2904
	υCH (94) in symm. str. CH2	2915	2914	2911	2888
	υOC (72) in C23–O24 and C29–O30	1735	1743	1720	1764
	υOC (92) in C23–O24 and C29–O30	1725	1725	1718	1721
	υOC (72) in O14–C1	1693	1694	1683	1721
	υNC (53) in N13–C4 + υCC (18) in ring 1	1605	1609	1593	1623
	υCC (47) in ring 1 + υNC (14) in N13–C4 + δCCC (10) in ring 1	1570	1578	1580	1601
	υCC (53) in ring 1 + δCCC (30) in ring 1	1514		1539	1559
	δHCH (67) in the CH3 asym. def. and CH3 twisting mode	1442	1455	1446	1445
	δHCC (39) in ring 1 + δCCC (22) in ring 1	1442	1431	1444	1436
	δHCH (70) in CH3 asymm. def. + τHCCN (14) in H17–C15–C4–N13	1426	1431	1436	1425
	υCC (37) in ring 1 + δHCC (34) in ring 1	1426	1431	1435	1417
	δHCH (58) in CH3 asymm. def. + τHCCN (13) in H33–C31–C29–N22	1426	1431	1429	1415
	δHCH (74) in CH3 asymm. def. + τHCCN (13) in H33–C31–C29–N22	1409	1406	1414	1405
	δHCH (72) in CH3 asymm. def.	1409	1406	1413	1402
	δHCH (84) in CH2 sciss.	1409	1406	1406	1389
	δHCH (68) in CH3 asymm. def.	1409	1382	1398	1384
	δHCH (79) in CH3 symm. Def.	1364	1363	1366	1353
	δHCH (81) in CH3 symm. Def.	1364	1363	1349	1344
	δHCH (60) in CH3 symm. Def.	1328	1333	1344	1339
	τHCCN (33) in H17–C15–C4–N13 and CH2 wagging mode in the ethyl group	1328	1333	1337	1331
	υCC (72) in ring 1	1295		1304	1304
	υNN (12) in N22–N35	1295	1272	1272	1292
	δHCC (28) in ring 1 + υNC (11) in N13–C3 + υCC (10) in ring 1 + υNNv (10) in N22–N35	1263	1272	1268	1260
	δHCC (63) in H17–C15–C18 and H21–C18–C15 and twisting mode CH2 in the ethyl group + τHCCN (14) in H17–C15–C4–N13	1240	1247	1246	1246
	υNC (13) in N13–C3 and N22–C29	1240	1230	1235	1227
	υCC (11) in ring 1 + δHCC (10) in ring 1 + δCCC (10) in ring 1	1214	1230	1208	1218
	υNC (28) in C1–N35 and N22–C23	1188	1192	1190	1198
	υNC (24) in C1–N35 and N22–C23 + δHCC (11) in ring 1	1188	1192	1180	1195
	δHCC (10) in ring 1 and H28–C25–C23 + υNN (10) in N22–N35	1149	1149	1157	1168
	δHCC (56) in ring 1	1110	1100	1127	1109
	δHCC (38) in ring 1 + δCCC (10) in ring 1	1100	1100	1089	1082
	υCC (23) in C18–C15	1058		1069	1076
	τHCCN (43) in H17–C15–C4–N13 + δHCH (10) in H17–C15–H16 and H21–C18–H19	1058		1062	1045
	τHCCC (10) in CH3 rocking + τHCCN (10) in H33–C31–C29–N22	1038	1026	1035	1038
	τHCCC (38) in CH3 rocking + γONCC (12) in O24–C23–N22–N35 + δHCH (12) in H28–C25–H27	1025	1026	1019	1019
	τHCCN (41) in H32–C31–C29–N22 + δHCH (13) in H33–C31–C32	1025	1026	1017	1012
	τHCCN (20) in H33–C31–C29–N22	1025	1026	1012	1009
	τHCCN (13) in H17–C15–C4–N13	1025	1026	1009	1005
	υCC (33) in ring 1	979	990	998	999
	τHCCC (83) in ring 1 out of plane H	970		969	972
	τHCCC (74) in ring 1 out of plane H + τCCCC (11) in ring 1 out of plane C	944	947	951	956
	υCC (25) in C18–C15 and C25–C23 + τHCCC (10) in the H20–C18–C15–C4/CH3 rocking mode	944		948	955
	υCC (32) in C18–C15 and C25–C23	944		910	918
	υCC (40) in C29–C31	878	879	898	910
	τHCCC (77) in ring 1 out of ring H + γNCCC (10) in N13–C3–C7–C2	878	879	862	864
	δCCC (31) in ring 1 + υNC (10) in N13–C3	878	879	856	849
	τHCCN (42) in H17–C15–C4–N13 and rocking mode CH3 in the ethyl group + γCNNC (12) in C1–N35–C4–N13	803	794	782	784
	υNC (11) in C4–N35 + υCC (10) in C23–C25	774	769	777	775
	γONCC (24) in O14–N35–C1–C2 + τHCCC (16) + τCCCC (12)	774		774	767
	τHCCC (51) out of ring H + τCNCC (10) in C4–N35–C1–C2	774		757	752
	τCCCC (18) out of ring 1 C + τHCCC (15) out of ring 1 H	680		682	677
	τCCCC (26) out of ring 1 C	660	665	659	657
	δCCC (48) in ring 1 and C4–C15–C18	647	647	649	648
	υCC (16) in C2–C3 + δOCC (15) in O24–C23–C25	618		624	626
	τCNCN (20) in C3–N13–C4–N35 + τCCCC (13) in ring 1 + τCCCN (13) in C3–C2–C1–N35 + γCNNC (12) in C1–N35–N22–C23	601	598	608	605
	δOCC (27) in O24–C23–C25 + υCC (11) in C15–C4	601	598	591	592
	γONCC (39) in O24–N22–C29–C25	572	580	584	582
	γONCC (15) in O24–N22–C29–C25 + δOCC (15) in O24–C23–C25	562	542	557	556
	γONCC (50) in O24–N22–C29–C25	543	542	551	548
	δCCC (14) in ring 1	520		527	526
	τCCCC (18) out of ring 1 + γNCCC (12) in N13–C3–C2–C6 + γCNNC (10) in C4–N3–N22–C23	520		507	503
	δCCC (27) in C4–C15–C18 and in ring 1	461	463	452	449
	τCCCC (24) out of ring 1 + γNCCC (10) in N13–C3–C2–C6	461	420	446	444
	τCCCC (27) out of ring 1	419		407	409
	δNNC (15) in N22–N35–C4 + δOCC (13) in O14–C1–C2 + υNC (11) in N22–C23			394	400
	δOCC (14) in O14–C1–C2 + δCCN (18) in C25–C23–N22			391	393
	δCCN (57) in C25–C23–N22		365	355	363
	δCNN (25) in C29–N22–N35 + δCCC (12) in C18–C15–C4		365	346	353
	δCCN (18) in C25–C23–N22 + δCCC (11) in C18–C15–C4		328	314	325
	τCCCC (30) out of ring 1 + γCNNC (12) in C3–C4–N35–C1		297	291	289
	δNCC (36) in N22–C23–C25		297	287	285
	τHCCN (56)		218	229	251
	δCNC (25) in C23–N22–C29 + δCCN (13) in C15–C4–N13 + τHCCC (10)		218	202	226
	τHCCC (45)		218	194	211
	τHCCN (83) in H33–C31–C29–N22		162	182	203
	τCNCC (37) in C4–N13–C3–C2 + γNCCC (15) in N13–C4–C15–C18		162	156	156
	δCCN (21) in C15–C4–N13 + δCCC (18) in C18–C15–C4 + δCNC (10) in C1–N35–C4		132	153	153
	τCNCN (35) in C3–N13–C4–N35 + γNCCN (12) in N13–C4–C15–N35		132	122	120
	τCNCN (25) in C3–N13–C4–N35 + γCNNC (16) + γNCCC (10) + τCCCC (10)			105	97
	γCNCN (52) + γNCCN (12) + τCNCN (10)			95	88
	τCCNN (32) + τCNCN (28) + γCNCN (10)			71	71
	τCCNN (71) + δNNC (14)			63	62
	τCCNN (61) + γNCCN (15)			60	57
	τCCNN (37) + γNCCN (13) + τCNCN (13)			43	44
	τCNCN (45) + γNCCN (29)			39	37
				0.9998	0.9997

, stretching; , in-plane bending; , out-of-plane bending; , torsion.
Potential energy distribution (PED); values less than 10% are not shown.