Table 1. Details of Noncovalent Interactions in the Eight Lowest Conformers (See Table S1 for the Additional Information of the Energy for the Eight Lowest Conformers)^a.

conformation	ΔG (kcal/mol, SATP)*	Interaction	ρ** (a.u)	distance*** (Å)	distance for charge delocalization**** (Å)
#1	0.0	–O10H...O11=C6—	0.033	1.84	1.34, 1.35, 1.23
		2(−CH3)...O11=C6—	0.012	2.45
#2	0.45	2(−CH3)...O11=C6—	0.012	2.45	1.35, 1.36, 1.22
		–Cα8H...O11=C6—	0.010	2.58
		–O10H...(lp)–N7–	0.010	2.60
		–C12H3...(lp)–O10–	0.009	2.71
		–C9H2...O11=C6—	0.007	2.76
#3	0.52	2(−CH3)...O11=C6—	0.012	2.45	1.35, 1.36, 1.22
		–N7H...(lp)–O10–	0.010	2.47
		–Cα8H...O11=C6—	0.010	2.51
		–C12H3...(lp)–O10–	0.008	2.65
		–C12H3...O11=C6—	0.004	3.07
#4	0.80	–O10H...O11=C6–	0.034	1.82	1.35, 1.36, 1.23
		2(−CH3)...O11=C6–	0.012	2.44
		–C12H3...O11=C6–	0.007	2.80
		–C12H3...(lp)–O10–	0.010	2.70
#5	0.91	2(−CH3)...O11=C6–	0.012	2.44	1.35, 1.36, 1.22
		–N7H...(lp)–O10–	0.008	2.49
		–Cα8H...O11=C6–	0.008	2.56
		–C12H3...O11=C6–	0.005	2.93
#6	0.92	2(−CH3)...O11=C6–	0.012	2.45	1.35, 1.36, 1.22
		–Cα8H...O11=C6–	0.009	2.53
		–C12H3...(lp)–O10–	0.009	2.66
		–C9H2...O11=C6–	0.006	2.89
#7	1.0	2(−CH3)...O11=C6–	0.012	2.45	1.35, 1.36, 1.22
		–Cα8H...O11=C6–	0.010	2.52
		–C12H3...(lp)–O10–	0.009	2.58
		–C9H2...O11=C6–	0.005	2.94
#8	1.3	–Cα8H...(lp)–O5–	0.016	2.32	1.34, 1.37, 1.22
		–O10H...(lp)–N7–	0.014	2.42
		2(−CH3)...O11=C6—	0.012	2.45

^a*Relative Gibbs free energy calculated at standard ambient pressure and temperature (1 atm and 298.15 K), **the electron density at the critical point, ***the minimum distances between hydrogen and functional group, and **** d(O₅-C₆), d(N₇-C₆), and d(O₁₁-C₆), respectively.