. 2020 Apr 4;26(5):93. doi: 10.1007/s00894-020-4343-6

Table 2.

Gas-phase metal cation basicities (LiCA, LiCB, NaCA, and NaCB at 298 K in kJ mol⁻¹) for purine, imidazole, and pyrimidine

Compound	Method	LiCA	LiCB	NaCA	NaCB
P⁻	DFT^a	617.5^b	584.5^b	529.2^b	496.8^b
P	DFT^a	226.9^b,c	194.3^b,c	170.1^b,c	138.5^b,c
Im⁻	DFT^a	636.1^b	601.0^b	527.4^b	494.6^b
	G2	627.0^b	592.5^b	520.0^b	487.4^b
	G2MP2	626.4^b	592.0^b	519.6^b	487.1^b
	G3	639.0^b	604.5^b	545.5^b	513.0^b
	G3B3	639.3^b	604.5^b	546.0^b	513.0^b
Im	DFT^a	216.9^d	185.9^d	155.9^b	126.4^b
	G2	206.3^b	175.9^b	145.4^b	116.7^b
	G2MP2	205.9^b	175.4^b	145.1^b	116.4^b
	G3	211.9^b	181.4^b	157.6^b	128.9^b
	G3B3	212.0^b	181.4^b	157.5^b	128.5^b
	Exp	213.2^e	172.3^e
Pym	DFT^a	168.7^b	138.2^b	114.7^b	85.7^b
	G2	158.1^b	128.2^b	104.4^b	76.3^b
	G2MP2	157.9^b	128.0^b	104.4^b	76.2^b
	G3	162.6^b	132.7^b	115.5^b	87.4^b
	G3B3	162.8^b	132.7^b	115.6^b	87.1^b
	Exp	156.3 ± 10^f	128.3 ± 10^f	103.5 ± 4^f	76.0 ± 4^f

^aB3LYP/6–311 + G(d,p). ^bThis work. ^cFor estimation, the percentage contents of neutral tautomers P7 and P9 were taken into account. ^dRef [91]. ^eRevised value taken from ref. [91]. ^fTaken from ref. [101]