Study of the Topological Properties of Some Pseudohalides

The pseudohalide principle has been used extensively in nonmetal chemistry to predict the structure and stability of many molecular species. The 1,2,3,4-thiatriazole-5-thiolate anion, CS2N3-, is of particular interest. In a short communication we have recently reported the topological study of some CS2N3-containing species reported by Crawford et al. Previous reports on these compounds showed that in covalent derivatives not only does the ring remain intact but also the site of attachment of the R group is most likely at the exocyclic sulfur atom in contrast to the previously suggested N−R connectivity. Therefore, the structure and bonding of derivatives of the CS2N3- moiety is clearly an important question. With that in our mind, we undertook a topological analysis, based on the AIM theory, to gain more insight into the bonding in covalent derivatives of the CS2N3- moiety, trying to find an explanation to the origin of the N−H and S−H connectivities. The question is which is the reason that makes all the covalent derivatives prefer the S−R connectivity while the hydracid has an N−H one.