Fukui Function Analysis and Optical, Electronic, and Vibrational Properties of Tetrahydrofuran and Its Derivatives: A Complete Quantum Chemical Study

Table 6

Vibrational assignments of 1,2,3,4-tetra-amino tetrahydrofuran (modes having high IR intensity only) with B3LYP/6-311 G (d, p).

B3LYP (calculated) unscaled	B3LYP (calculated) scaled	IR (int.)	Vibrational assignments
260	250	43.2432	Twist NH2
301	290	22.3762	Twist NH2
347	334	25.9587	Rock NH2
366	352	21.3354	Rock NH2
426	410	18.1696	Twist NH2
513	494	54.7952	Torsion in whole molecule
593	571	38.3343	(C–C–O–C)
663	638	28.8211	(C–C–C–C)
759	731	56.9814	(C–C–C–O)
802	772	106.1627	Rock NH2
850	819	60.9417	Rock NH2
865	833	73.3106	Twist NH2 in whole places
881	848	335.8006	Twist NH2
902	869	149.2133	Rock NH2
944	909	85.627	Rock NH2
972	936	31.7804	(C–C–C) + Twist NH2
1019	981	132.2283	(C–O)
1097	1056	16.8407	Twist NH2
1167	1124	27.6511	Bending in whole molecule
1183	1139	25.494	(C–C–H)
1441	1388	19.585	(C–C–H)
1635	1575	55.77	S(NH2)
1649	1588	56.9828	S(NH2)
2946	2837	39.5477	(C–H)
2984	2874	58.3297	(C–H)
3033	2921	82.6875	(C–H)
3483	3354	19.1928	(N–H)
3585	3452	11.9623	(N–H)