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

Table 3.

Maxima of the torsional barrier, ΔE_max, for the rotation of the (3–2–1′–6′) dihedral angle in the studied flavonoids computed in gas phase at the B3LYP/6-311++G** theoretical level. All the maxima appear at τ = 90° (Figure 3).

Compound	ΔE_max/kcal mol⁻¹	Compound	ΔE_max/kcal mol⁻¹

Flavone	3.44	IX	4.59
I	3.48	X	4.67
II	3.50	XI	5.09
III	3.83	XII	4.41
IV	3.39	XIII	5.01
V	3.77	XIV	4.59
VI	3.46	XV	4.64
VII	3.66	XVI	5.71
VIII	3.84