Table 2.

Bond energies (∆E in kcal/mol) of protonated quartets (ZORA-BLYP-D3/QZ4P), either in a relaxed structure (C₂ symmetry) or constrained to planarity (C_2h symmetry)

Quartet	C2 symmetry		C2h symmetry
	∆E (gas phase)	∆E (water)	∆E (gas phase)	∆E (water)
(H·I)2	− 73.6	− 30.3	− 73.9	− 28.6
(H·II)2/(III)2	− 73.9	− 30.3	− 73.2	− 29.0
(III′)2	− 68.0	− 23.6	− 68.0	− 23.4

Selected geometrical parameters of the quartets are provided in Table S2