A Computational Study on 3‐Azonia‐, 3‐Phosphonia‐, and 3‐Arsoniaspiro[2.2]pentanes and Related Three‐Membered Heterocycles

Abstract

A theoretical study at the ab initio MP2/6‐311++G(d,p) level of theory is carried out to characterize several heterocyclic spiro[2.2]pentane cations with N, P, and As as spiro atoms. The strain and relative stability of the spiropentanes are obtained through isodesmic reactions. Nucleus‐independent chemical shifts (NICS) and 3D NICS isosurfaces show σ‐aromatic characteristics, similar to those found in cyclopropane. The interaction with the Cl− anion, which results in four different stationary structures, is studied and characterized by means of the atoms in molecules methodology, and Cl⋅⋅⋅pnicogen, Cl⋅⋅⋅H, and Cl⋅⋅⋅C interactions are found. The most stable structure in all cases corresponds to 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 the 3‐boranuidaspiro[2.2]pentane anion results in the formation of a new compound through cleavage of one ring of both reactants.

Protonated and Sodiated Cyclophosphamide Fragmentation Pathways Evaluation by Infrared Multiple Photon Dissociation Spectroscopy

“…It should also be highlighted that the aziridineaziridinium cation with m / z 70 was evaluated theoretically previously − as it was suggested to explain the formation of an ion with m / z 70 formed by phenotiazines and thioproperazines and considered a plausible species . Nevertheless, even being less plausible, the presence of aziridinium motifs for these ions cannot be experimentally verified as they yield undistinguishable IRMPD spectra in the IR range available in our experimental setup and requires further evaluation in the fingerprint region.…”