Table 2.

Energies of the clusters in OH- and cis-NH-forms, along with the proton transfer energy (Δ_PTE in kJ mol⁻¹). Comparison among ONIOM and full DFT calculations

	ONIOM (DFT: HF-D)	Full DFT-D
	B3LYP/6-311G**: HF-D3BJ/6-31G*	B3LYP-D3BJ/6-311G**	B97XD/6-311G**
α-SA4B	13.35	14.68	18.41
α-SA4C	13.17	14.37	18.09
β-SA4C	9.89	11.14	14.79