The N⋯HF Interactions in the X-Pyridazine⋯ (HF)_𝟐 Complexes: Substituent Effects and Energy Components

Table 1

The N⋯H bond lengths optimized at the B3LYP/6-311++G(d,p) level in (Å) and the Hammett constants.

	Bond length			Hammett constants
	Complex 1	Complex 2	Complex 3	σ m	σ p	σ total	σ I	σ R
N(CH3)2	1.67 (1.69)	1.64	1.63	−0.15	−0.83	−0.98	0.15	−0.98
NHCH3	1.68 (1.70)	1.65	1.63	−0.52	−0.74	−1.26	0.03	−0.73
NH2	1.68 (1.71)	1.65	1.64	−0.16	−0.66	−0.82	0.08	−0.74
CH3	1.71 (1.71)	1.66	1.66	−0.07	−0.17	−0.24	0.01	−0.18
C2H5	1.71 (1.71)	1.66	1.66	−0.07	−0.15	−0.22	0.00	−0.15
OCH3	1.70 (1.72)	1.67	1.65	0.12	−0.27	−0.15	0.29	−0.56
OH	1.71 (1.73)	1.67	1.66	0.12	−0.37	−0.25	0.30	−0.70
H	1.72 (1.72)	1.67	1.67	0.00	0.00	0.00
OF	1.73 (1.74)	1.70	1.68	0.47	0.36	0.83
CN	1.75 (1.70)	1.71	1.70	0.56	0.66	1.22	0.51	0.15
NO2	1.76 (1.76)	1.72	1.71	0.71	0.78	1.49	0.60	0.13
F	1.73 (1.74)	1.69	1.68	0.34	0.06	0.40	0.45	−0.39
Br	1.73 (1.74)	1.69	1.69	0.39	0.23	0.62	0.40	−0.22
Cl	1.73 (1.74)	1.69	1.68	0.37	0.23	0.60	0.42	−0.19

The data in the parentheses correspond to the N₂⋯H bond length. The σ values are taken from [37].