Table 2.

Energy barriers and spin densities for the C-H and N-H activations with EEFs oriented parallel to the Fe(IV)=O bond reaction axis, calculated at the B1 and B2+ZPE levels of theory.

Electric field strength (au)	Barrier for C-H (kcal/mol)	Barrier for N-H (kcal/mol)	Difference (kcal/mol)	Spin density of Fe of Fe(IV)=O in C-H	Spin density of O of Fe(IV)=O in C-H	Spin density of Fe of Fe(IV)=O in N-H	Spin density of O of Fe(IV)=O in N-H
−0.0075	24.2/21.9	42.2/34.1	18.0/12.2	3.181	0.543	3.149	0.605
−0.0050	23.1/21.8	44.1/37.6	21.0/15.8	3.164	0.557	3.156	0.597
−0.0025	18.6/18.8	44.8/39.1	26.2/20.3	3.152	0.567	3.169	0.580
0.0000	17.5/16.3	31.8/26.5	14.3/10.2	3.136	0.582	3.145	0.619
0.0025	16.8/16.0	43.9/36.4	27.1/20.4	3.126	0.590	3.152	0.601
0.0050	14.5/13.8	42.6/38.7	28.1/25.2	3.114	0.601	3.164	0.587
0.0075	12.4/12.1	45.6/40.4	33.2/28.3	3.100	0.615	3.173	0.572