The adsorption of parent nitrosamine (NA) on the Brønsted acid sites of M-ZSM-5 (M = H, Li and Na) zeolites have been investigated via the utilization of 10T cluster model by density functional calculations, at the B3LYP/6-311++G(d,p) level. Two A and B complexes with two types O(N)…M and NH…O$_Z$ interactions were predicted from adsorption of nitrosamine on the M-zeolite clusters. The comparison of interaction energies shows that the order of energies for adsorption of NA on the Brønsted acid site of M-ZSM-5 is Na Li < H for the A complexes and Li < H for the B complexes. The calculated adsorption enthalpy of NA on the Brønsted acid site of 10T cluster of M-ZSM-5 catalyst ranges from −14.41 to −52.95 kJ/mol. The acid strength of H-ZSM-5 was found to exceed those of the corresponding to the alkali metal ion-exchanged zeolites. The results reveal that the interaction between hydrogen of NA and O$_Z$ of framework is weaker than O(N)…M one. The NH…O$_Z$ and O(N)…H$_Z$ hydrogen bonds in these complexes are electrostatic and partially covalent in nature, respectively. The results of natural bond orbital (NBO) analysis showed that charge transfer occurs from NA to M-zeolite cluster.

The synergistic relationship between pnictogen and halogen non-covalent interactions in 4-YPhNH₂...PH₂F...ClX (Y = H, F, CN, CHO, NH₂, CH₃, NO₂ and OCH₃; X = F, OH, CN, NC, FCC and NO₂) complexes were explored using Aug-ccpVDZ basis set and M06-2X and M06-2X-GD3, B2PLYP-GD3and mPW2PLYP-GD2 functionals. The effects of the substituents included at pnictogen bond and halogen bond segments on the correlation between BEs and pnictogen as well as halogen bond distances, electron density at both non-covalent interactions, charge transfer energies between components and the NMR properties were evaluated. The energy analysis indicates that the pnictogen bond interaction has a much greater stabilizing effect than the halogen bond one. In addition, the auxiliary effect of a pnictogen bond on a halogen bond is more pronounced than that of a halogen bond on a pnictogen bond