Study on supramolecular complexing ability vis-à-vis estimation of pKa of substituted sulfonamides: dominating role of Balaban index (J).

The supramolecular complexing ability vis-à-vis pKa estimation of a large series of 43 sulfonamides was made using a series of molecular descriptors including topological indices. The set of topological indices chosen also contains Balaban (J) and a variety of Balaban type indices: J, Jz, Jm, Jv, Jc, and Jp. The results have shown that the most discriminating Balaban index (J) in multi-parametric regression analysis combined with indicator parameters yields excellent models and also establishes the superiority of the J index over other Balaban type indices. The statistics is improved when one of the indicator parameters is replaced by molar volume (MV). The results are discussed critically using a variety of statistics.