C. Trujillo, G. Sánchez-Sanz, I. Alkorta, J. Elguero
A computational study of 3-azonia-, 3-phosphonia- and 3-arsonia- spiro[2.2]pentanes and related three-membered heterocycles
A theoretical study, using ab initio MP2/6-311++G(d,p) computational level, has been carried out to characterize several heterocyclic spiro[2.2]pentanes cations, with N, P and As as spiro atoms. The strain and relative stability of the spiropentanes has been obtained through isodesmic reactions. NICS values and 3D NISC isosurfaces have shown σ-aromatic characteristics, similar to those found in cyclopropane. The interaction with the Cl– anion, resulting in four different stationary structures has been studied and characterized by means of the Atoms in Molecules (AIM) methodology, and it has been found Cl-pnicogen, Cl-H and Cl-C interactions have. Amongst them, the most stable structure in all cases corresponds to the opening of one of the three membered rings due to the attack of the Cl atom and C-Cl bond formation. Furthermore, the reaction with 3-boranuidaspiro[2.2]pentane anion has been considered, resulting in the formation of a new compound through the cleavage of the carbon rings of both reactants.