Description of the Various SOAz Structures

A perspective view of one of the molecules isolated, (NPAz2)2(NSOAz), is shown in Fig. 40 the chosen model belongs to SOAz (I). In this Fig., obtained using the program Ortep of Johnson the numbering of the atoms is indicated, and is identical for both structures SOAz (I) and SOAz (II) (molecules A and B). 

These three molecules, with quasi-planar six-membered rings (Table 16), do not admit any symmetry. Table 15 allows an easy comparison of the details of these molecules, the main differences being at the level of the conformations, the aziridino groups rotating around the P—N and S—N directions. 

A joint view, projection on the plane of the ring, of these three types of SOAz 

The packing of the molecules (without H atoms) in both allotropic forms SOAz (I) and (II) is visualized by means of the projection on to the planes (001) and (010) (Figs. 42 and 43) for SOAz (II), half of the cell content was drawn for the sake of clarity (the helicoYdal twofold axes have not been u ). 

Coming back to the molecular structures of SOAz (I), SOAz (II A) and SOAz (IIB), it is noticeable that the conformations of their aziridinyl ligands differ drastically from one allotropic form to the other. In other words, the molecule of SOAz appears to be a versatile molecule with respect to its aziridinyl groups. There is, at the moment, no ready explanation for the adoption of either the one or the other conformation when the synthesis is repeated under exactly the same experimental conditions. However, the SOAz molecule seems to be extremely flexible with regard to the orientation of its wings , even more flexible than that of N3P3AZg 3 15  

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