Can descriptors of the electron density distribution help to distinguish functional groups?

Our study is aimed at understanding the characteristics of functional group descriptors based on peaks of the electronic density distribution rho(->r) . The descriptors calculated are the rho(->r) value at peak location, volume, ellipticity, curvatures of rho ( r) , and the peak-functional group distance. By the implementation of an automated and global process for large-scale calculation of the descriptors, we generated a statistically meaningful data set focusing on the association between peaks and 77 types of functional groups extracted from 62,936 organic molecules issued from the Cambridge Structural Database. Statistical analyses demonstrated that selected descriptors are capable of discriminating subtypes of functional groups. A projection in a principal component space coupled to a hierarchical clustering confirmed the suitability of the descriptors to provide an appropriate description of the functional groups. The results indicated that functional similarity or dissimilarity could be quantified based on electron density descriptors.