Table 4.

B3LYP/6-311++G(d,p) calculated relative electronic energies (ΔE_el), zero-point corrected relative energies (ΔE₍₀₎), standard Gibbs energies at 298.15 K (ΔG°_298.15), and dipole moments (μ) for the keto-amine conformers of BHAP ^a.

Conformer	ΔEel	ΔE(0)	ΔG°298.15	μ		ΔEel	ΔE(0)	ΔG298.15
keto-amine forms structurally related to the E-enol-imine isomer
I	19.69	18.94	16.35	3.49		2.75	2.66	2.39
II	16.95	16.28	13.96	5.30		0.00	0.00	0.00
III	61.49	61.03	56.80	4.74		2.95	2.86	3.82
IV	58.54	58.17	52.98	5.67		0.00	0.00	0.00
V	17.87	17.01	11.28	2.97		0.92	0.72	–2.68
VI	18.42	17.67	14.20	5.67		1.48	1.39	0.25
VII	58.66	58.14	52.81	3.82		0.12	–0.03	–0.17
VIII	59.08	58.45	52.93	6.41		0.54	0.28	–0.05
keto-amine forms structurally related to the Z-enol-imine isomer
I	80.86	81.47	78.49	4.46		63.91	65.19	64.53
II	82.00	82.43	79.19	6.89		65.05	66.15	65.23
III	94.97	94.96	93.91	4.53		36.43	36.79	40.93
IV	92.80	92.95	92.27	4.05		34.26	34.78	39.29
V	82.94	83.08	79.48	5.39		65.99	66.80	65.52
VI	81.05	81.44	78.61	6.29		64.09	65.16	64.66
VII	91.88	92.47	92.00	3.91		33.34	34.30	39.02
VIII	93.01	93.29	92.87	4.75		34.47	35.12	39.89

^a Energies in kJ mol⁻¹; dipole moments in Debye. See Figure 4 for the structures of the conformers. The first set of energy values is relative to the most stable form, E-enol-imine V, and the second set is relative to the most stable conformer of each keto-amine isomer. Values in italic style are for E-keto-amine forms and values in round style for E-keto-amine forms.