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

Table 1.

Comparison of the calculated and experimental gas-phase proton basicities (PA and GB at 298 K in kJ mol⁻¹) for purine, imidazole, and pyrimidine

Compound	Method	PA_calc	GB_calc	PA_exp	GB_exp
P⁻	DFT^a	1389.4^b	1358.2^b	1393 ± 17^c
				1389 ± 12^d
P	DFT^a	925.5^b	893.3^b	920.1^e	888.2^e
				921 ± 12^c
				925 ± 12^d
Im⁻	DFT^a	1462.8^b	1431.3^b	1464.1^f	1433.4^f
	G2	1461.1^b	1429.8^b
	G2MP2	1461.9^b	1430.6^b
	G3	1464.0^b	1432.7^b
	G3B3	1463.9^b	1432.5^b
Im	DFT^a	946.0^b	913.7^b	942.8^e	909.2^e
	G2	944.0^b	911.7^b
	G2MP2	944.4^b	912.1^b
	G3	945.8^b	913.5^b
	G3B3	945.4^b	913.1^b
Pym	DFT^a	889.8^b	858.0^b	885.8^e	855.7^e
	G2	886.8^b	855.2^b
	G2MP2	887.2^b	855.5^b
	G3	887.4^b	855.7^b
	G3B3	887.2^b	855.4^b

^aB3LYP/6-311+G(d,p). ^bThis work. ^cRef [84], bracketing method. ^dRef [84], Cooks kinetic method. ^eRef [70]. ^fRef [86]