. 2010 May 3;11(5):2017–2038. doi: 10.3390/ijms11052017

Table 6.

NBO analysis of studied flavonoids monomers computed in gas phase at the B3LYP/6-311++G** theoretical level. Second order perturbation energy, E(2); energy difference among the donor and the acceptor, ΔE; and Fock matrix element between the donor and the acceptor, F_ij. Values calculated for optimized structures reported in Figure 2. Intramolecular H-bonding sites defined in Figure 4. The donor pairs belong to the oxygen and the acceptor is H–O (for HB_1, HB_2, HB_4 and HB_5) or H–C (for HB_3) for each H-bonding proposed in Figure 4. Reported values only for E(2) > 0.50 kcal mol⁻¹.

Comp.	H-bond	Donor pair	E(2)/kcal mol⁻¹	ΔE/a.u.	F_ij/a.u.	Comp.	H-bond	Donor pair	E(2)/kcal mol⁻¹	ΔE/a.u.	F_ij/a.u.
I	HB 1	1	2.61	1.07	0.047	XII	HB 1	1	2.61	1.11	0.048
I		2	18.25	0.68	0.101			2	13.10	0.68	0.086
II	HB 1	1	2.60	1.07	0.047		HB 2	1	0.60	1.10	0.022
II		2	18.17	0.68	0.101			2	3.60	0.67	0.045
III	HB 1	1	2.63	1.07	0.048		HB 3	1	1.61	1.09	0.039
III		2	18.45	0.68	0.102			2	No	No	No
IV	HB 1	1	2.62	1.07	0.047	XIII	HB 1	1	2.60	1.11	0.047
IV		2	18.35	0.68	0.101			2	13.35	0.68	0.087
V	HB 1	1	2.63	1.07	0.048		HB 2	1	0.60	1.10	0.023
		2	18.41	0.68	0.102			2	3.57	0.67	0.045
	HB 5	1	0.80	1.03	0.026		HB 3	1	1.62	1.09	0.038
		2	No	No	No			2	No	No	No
VI	HB 1	1	2.63	1.02	0.047		HB 5	1	0.79	1.03	0.025
VI		2	18.20	0.68	0.101			2	No	No	No
VII	HB 1	1	2.63	1.02	0.047	XIV	HB 1	1	2.62	1.11	0.049
		2	18.24	0.68	0.102			2	13.25	0.68	0.086
	HB 4	1	0.82	1.03	0.029		HB 2	1	0.60	1.10	0.023
		2	No	No	No			2	3.59	0.67	0.047
VIII	HB 1	1	2.63	1.02	0.048		HB 3	1	1.62	1.09	0.039
		2	18.25	0.68	0.103			2	No	No	No
	HB 4	1	0.81	1.03	0.027	XV	HB 1	1	2.61	1.11	0.049
		2	No	No	No			2	13.30	0.68	0.087
	HB 5	1	0.79	1.03	0.025		HB 2	1	0.61	1.10	0.023
		2	No	No	No			2	3.61	0.67	0.044
IX	HB 1	1	2.60	1.11	0.048		HB 3	1	1.62	1.09	0.040
		2	13.18	0.68	0.087			2	No	No	No
	HB 2	1	0.60	1.10	0.023		HB 4	1	0.82	1.03	0.031
		2	3.58	0.67	0.045			2	No	No	No
	HB 3	1	1.60	1.09	0.037	XVI	HB 1	1	2.60	1.11	0.048
		2	No	No	No			2	13.32	0.68	0.087
X	HB 1	1	2.59	1.11	0.048		HB 2	1	0.60	1.10	0.023
		2	13.07	0.68	0.086			2	3.58	0.67	0.046
	HB 2	1	0.60	1.10	0.023		HB 3	1	1.61	1.09	0.041
		2	3.62	0.67	0.045			2	No	No	No
	HB 3	1	1.58	1.09	0.037		HB 4	1	0.80	1.03	0.029
		2	No	No	No			2	No	No	No
XI	HB 1	1	2.62	1.11	0.048		HB 5	1	0.81	1.03	0.027
		2	13.40	0.68	0.087			2	No	No	No
	HB 2	1	0.58	1.10	0.022
		2	3.50	0.67	0.045
	HB 3	1	1.62	1.09	0.038
		2	No	No	No