Table 3. Hydration Enthalpies (M06-2x-SMD) for Singlet Nitrenium Ions.

entry	R1	R2		ΔHrel (kcal/mol, 298 K)	ΔHhyd (kcal/mol, 298 K)
1	H	H	1	0.00	–76.51a
2	H–CO	H	28	29.90	–46.61
3	CH3CO	H	25	41.36	–35.15
4	CH3	H	2	58.60	–17.91
5	CH3	CH3	3	64.87	–11.64
6	H–CO	CH=CH2	31	70.36	–6.15
7	CH3CO	OCH3	33	74.67	–1.84
8	CH2=CH–	H	19	75.02	–1.49
9	H–CO	OCH3	32	75.38	–1.13
10	CH3O	H	25	76.64	0.13
11	CH3O	C(CH3)3	27	79.53	3.02
12	CH3O	CH3	26	80.23	3.72
13	CH2=CH–	C(CH3)3	21	82.17	5.66
14	CH2=CH–	CH3	20	82.81	6.30
15	Ph	C(CH3)3	24	83.79	7.28
16	Ph	H	22	84.30	7.79
17	Ph	CH3	23	88.30	11.79
18	cyclopropyl	H	15	91.85	15.34
19	cyclopropyl	CH3	16	98.41	21.90
20	cyclobutyl	H	18	99.26	22.75
21	cyclopropyl	C(CH3)3	17	101.45	24.94

^aA CBS-APNO calculation using an SMD-simulated aqueous solvation.