title: Competition and interplay between σ-hole and π-hole interactions: a computational study of 1:1 and 1:2 complexes of nitryl halides (O2NX) with ammonia.
abstract: Quantum calculations at the MP2/cc-pVTZ, MP2/aug-cc-pVTZ, and CCSD(T)/cc-pVTZ levels have been used to examine 1:1 and 1:2 complexes between O(2)NX (X = Cl, Br, and I) with NH(3). The interaction of the lone pair of the ammonia with the σ-hole and π-hole of O(2)NX molecules have been considered. The 1:1 complexes can easily be differentiated using the stretching frequency of the N-X bond. Thus, those complexes with σ-hole interaction show a blue shift of the N-X bond stretching whereas a red shift is observed in the complexes along the π-hole. The SAPT-DFT methodology has been used to gain insight on the source of the interaction energy. In the 1:2 complexes, the cooperative and diminutive energetic effects have been analyzed using the many-body interaction energies. The nature of the interactions has been characterized with the atoms in molecules (AIM) and natural bond orbital (NBO) methodologies. Stabilization energies of 1:1 and 1:2 complexes including the variation of the zero point vibrational energy (ΔZPVE) are in the ranges 7-26 and 14-46 kJ mol(-1), respectively.
authors.affiliation: Quantum Chemistry Group, Department of Chemistry, Faculty of Sciences, Arak University, Arak 38156-8-8349, Iran. m-solimannejad@araku.ac.ir
authors.forename: Mohammad
authors.initials: M
authors.lastname: Solimannejad
authors.forename: Vahid
authors.initials: V
authors.lastname: Ramezani
authors.forename: Cristina
authors.initials: C
authors.lastname: Trujillo
authors.forename: Ibon
authors.initials: I
authors.lastname: Alkorta
authors.forename: Goar
authors.initials: G
authors.lastname: Sánchez-Sanz
authors.forename: José
authors.initials: J
authors.lastname: Elguero
mesh_terms: D000641:Ammonia / Q000737:chemistry*; D004583:Electrons; D009573:Nitrites / Q000737:chemistry*; D011789:Quantum Theory; D013816:Thermodynamics
chemical_list: D009573:Nitrites; D000641:Ammonia; C445660:nitryl chloride