Table 1: The N H bond lengths optimized at the B3LYP/6-311++G(d,p) level in ( ) and the Hammett constants.

Bond lengthHammett constants
Complex 1Complex 2Complex 3σ mσ pσ totalσ Iσ R

N(CH3)21.67 (1.69)1.641.63−0.15−0.83−0.980.15−0.98
NHCH31.68 (1.70)1.651.63−0.52−0.74−1.260.03−0.73
NH21.68 (1.71)1.651.64−0.16−0.66−0.820.08−0.74
CH31.71 (1.71)1.661.66−0.07−0.17−0.240.01−0.18
C2H51.71 (1.71)1.661.66−0.07−0.15−0.220.00−0.15
OCH31.70 (1.72)1.671.650.12−0.27−0.150.29−0.56
OH1.71 (1.73)1.671.660.12−0.37−0.250.30−0.70
H1.72 (1.72)1.671.670.000.000.00
OF1.73 (1.74)1.701.680.470.360.83
CN1.75 (1.70)1.711.700.560.661.220.510.15
NO21.76 (1.76)1.721.710.710.781.490.600.13
F1.73 (1.74)1.691.680.340.060.400.45−0.39
Br1.73 (1.74)1.691.690.390.230.620.40−0.22
Cl1.73 (1.74)1.691.680.370.230.600.42−0.19

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