Quantum Mechanical Study on the Structure and Vibrational Spectra of Cyclobutanone and 1,2-Cyclobutanedione

Table 1

Bond lengths (Å) and bond angle of 1,2-cyclobutanedione and cyclobutanone.

Cyclobutanone		Cyclobutane 1,2-dione
Parameters	Theoretical values; B3PW91/6-31G (d, p)	Parameters	Exp. data (X-Ray data)	Theoretical values
				B3LYP/6-31G (d, p)	B3PW91/6-31G (d, p)	MP2/6-31G (d, p)	LSDA/6-31G (d, p)
Bond lengths
C1–C2	1.53	C1–C2	1.561	1.58	1.58	1.57	1.57
C1–C4	1.55	C1–C4	1.524	1.55	1.54	1.55	1.53
C1–H10	1.10	C1=O5	1.19	1.20	1.20	1.21	1.20
C1–H11	1.09	C2–C3	1.52	1.55	1.54	1.55	1.53
C2–C3	1.53	C2=O6	1.196	1.20	1.20	1.21	1.20
C2=O5	1.20	C3–C4	1.54	1.55	1.55	1.54	1.53
C3–C4	1.55	C3–H7	0.99	1.09	1.09	1.09	1.10
C3–H6	1.09	C3–H8	0.99	1.09	1.09	1.09	1.10
C3–H7	1.10	C4–H9	0.99	1.09	1.09	1.09	1.10
C4–H8	1.09	C4–H10	0.99	1.09	1.09	1.09	1.10
C4–H9	1.09	C2–C1–C4	89.5	89.42	89.40	89.42	89.32
Bond angles
C2–C1–C4	88.19	C2–C1=O5	134.26	135.32	135.40	135.38	135.54
C2–C1–H10	112.46	C4–C1=O5	136.23	135.25	135.20	135.20	135.14
C2–C1–H11	114.89	C1–C2–C3	89.7	89.42	89.40	89.42	89.32
C4–C1–H10	114.90	C1–C2=O6	134.07	135.32	135.40	135.38	135.54
C4–C1–H11	117.34	C3–C2=O6	136.21	135.25	135.20	135.20	135.14
H10–C1–H11	108.12	C2–C3–C4	90.44	90.58	90.60	90.58	90.68
C1–C2–C3	92.35	C2–C3–H7	113.6	112.77	112.75	112.63	112.68
C1–C2=O5	133.81	C2–C3–H8	113.6	112.77	112.75	112.63	112.68
C3–C2=O5	133.81	C4–C3–H7	113.6	115.67	115.73	115.56	116.10
C2–C3–C4	88.19	C4–C3–H8	113.6	115.67	115.73	115.56	116.10
C2–C3–H6	114.87	H7–C3–H8	110.8	108.55	108.48	108.95	107.91
C2–C3–H7	112.44	C1–C4–C3	90.33	90.58	90.60	90.58	90.68
C4–C3–H6	117.37	C1–C4–H9	113.6	112.77	112.75	112.63	112.68
C4–C3–H7	114.94	C1–C4–H10	113.6	112.77	112.75	112.63	112.68
H6–C3–H7	108.11	C3–C4–H9	113.6	115.67	115.73	115.56	116.10
C1–C4–C3	90.80	C3–C4–H10	113.6	115.67	115.73	115.56	116.10
C1–C4–H8	115.12	H9–C4–H10	110.9	108.55	108.48	108.95	107.91
C1–C4–H9	113.26	C4–C1–C2–C3	1.12	0.00	0.00	0.00	0.00
C3–C4–H8	115.15	C4–C1–C2=O6	−177.2	180.01	180.01	180.00	180.00
C3–C4–H9	113.26	O5=C1–C2–C3	−178	−180.01	−180.01	−180.01	−180.00
H8–C4–H9	108.55	O5=C1–C2=O6	3.7	0.00	0.00	0.00	0.00
Dihedral angles
C4–C1–C2–C3	5.23	C2–C1–C4–C3	−1.11	0.00	0.00	0.00	0.00
C4–C1–C2=O5	−172.93	C2–C1–C4–H9		−118.30	−118.37	−118.14	−118.80
H10–C1–C2–C3	–111.05	C2–C1–C4–H10		118.30	118.37	118.14	118.80
H10–C1–C2=O5	70.79	O5=C1–C4–C3	178	180.01	180.01	180.01	180.00
H11–C1–C2–C3	124.70	O5=C1–C4–H9		61.71	61.64	61.87	61.21
H11–C1–C2=O5	−53.46	O5=C1–C4–H10		−61.69	−61.62	−61.85	−61.20
C2–C1–C4–C3	−5.16	C1–C2–C3–C4	−1.11	0.00	0.00	0.00	0.00
C2–C1–C4–H8	−123.58	C1–C2–C3–H7		−118.30	−118.37	−118.14	−118.80
C2–C1–C4–H9	110.69	C1–C2–C3–H8		118.30	118.37	118.14	118.80
H10–C1–C4–C3	108.84	O6=C2–C3–C4	−177.2	−180.01	−180.01	−180.00	−180.00
H10–C1–C4–H8	−9.58	O6=C2–C3–H7		61.69	61.62	61.86	61.20
H10–C1–C4–H9	−135.31	O6=C2–C3–H8		−61.71	−61.64	−61.86	−61.21
H11–C1–C4–C3	−122.39	C2–C3–C4–C1	1.14	0.00	0.00	0.00	0.00
H11–C1–C4–H8	119.19	C2–C3–C4–H9		115.74	115.74	115.56	115.80
H11–C1–C4–H9	−6.55	C2–C3–C4–H10		−115.74	−115.74	−115.56	−115.80
C1–C2–C3–C4	−5.23	H7–C3–C4–C1		115.74	115.74	115.56	115.80
C1–C2–C3–H6	−124.72	H7–C3–C4–H9		−128.52	−128.52	−128.88	−128.40
C1–C2–C3–H7	111.09	H7–C3–C4–H10		0.00	0.00	0.00	0.00
O5=C2–C3–C4	172.93	H8–C3–C4–C1		−115.74	−115.74	−115.56	−115.80
O5=C2–C3–H6	53.44	H8–C3–C4–H9		0.00	0.00	0.00	0.00
O5=C2–C3–H7	−70.76	H8–C3–C4–H10		128.51	128.52	128.88	128.40
C2–C3–C4–C1	5.16
C2–C3–C4–H8	123.55
C2–C3–C4–H9	−110.69
H6–C3–C4–C1	122.38
H6–C3–C4–H8	−119.22
H6–C3–C4–H9	6.53
H7–C3–C4–C1	−108.82
H7–C3–C4–H8	9.57
H7–C3–C4–H9	135.33