Table 4: The results of NBO analysis for the X-pyridazine (HF)n ( ) complexes at the HF/6-311++G(d,p) level of theory.

Complex 1Complex 2Complex 3
lpNσ * HF (× 102) lpNσ * HF (×102) lpNσ * HF (×102)

N(CH3)234.16, 30.47 1.911, 1.914 4.509, 5.030 39.481.9045.76742.411.9026.166
NHCH333.46, 29.71 1.912, 1.915 4.395, 4.934 38.661.9065.65141.791.9036.087
NH232.52, 28.72 1.913, 1.917 4.236, 4.793 37.351.9085.43840.051.9055.838
CH328.59, 27.95 1.919, 1.920 4.148, 4.239 36.071.9115.28936.441.9105.333
C2H528.94, 28.42 1.919, 1.919 4.213, 4.288 36.621.9105.39436.911.9105.399
OCH329.60, 27.51 1.917, 1.920 5.604, 5.946 35.081.9125.10137.701.9005.503
OH29.01, 25.99 1.918, 1.921 3.859, 4.286 34.391.9125.03136.121.9105.273
H26.79, 26.73 1.921, 1.921 3.982, 3.982 34.691.9125.09334.691.9125.093
OF25.44, 23.61 1.922, 1.924 4.931, 5.238 30.951.9184.52032.491.9154.760
CN22.58, 22.52 1.928, 1.926 3.348, 3.352 28.571.9194.20029.041.9214.259
NO221.48, 21.68 1.929, 1.928 4.566, 4.556 27.261.9223.99327.641.9224.041
F25.50, 23.92 1.922, 1.925 3.533, 3.785 30.951.9184.52032.631.9144.774
Br25.29, 24.36 1.923, 1.923 3.622, 3.757 31.141.9154.57532.231.9164.723
Cl25.36, 24.28 1.923, 1.923 3.602, 3.763 31.161.9164.57032.401.9154.745

The values are in kcal mol−1. The bold and italicized values correspond to the N1 H and N2 H bonds, respectively.