Comparable study of the structure of 1,2-bis(2-acetamidoethyl) diaziridine and 3,3-diethyldiaziridine with structures of related compounds by X-ray diffraction analysis and quantum chemical calculations

The crystal structures of 1,2-bis(2-acetamidoethyl)diaziridine and 3,3-diethyldiaziridine have been determined by single-crystal X-ray diffraction study. The studied diaziridine molecules have C-2 total group symmetry. The conformation of the studied molecules is similar to those of other diaziridines. A topological study within the framework of Bader's atoms in molecule (AIM) theory was performed for these molecules, their analogs and related compounds. From AIM and natural bond orbital (NBO) analysis data, an influence of the intramolecular interaction on chemical bonds was described and quantified. It was found that the N-N bond length increases on going from acyclic to cyclic molecules in accordance with increasing p-character of sigma(N-N) bonding orbitals. The lengthening of N-N bond lengths in diaziridine molecules in most cases is accompanied with increasing of the bond ellipticities demonstrating the pi-component contribution to these bonds.