2,5-diphenyloxazole and 4-pyrrolidinopyridine as conformers to picric acid: Structural characterization coupled with Multivariate Statistical Analysis

Abstract

In this study, 4-pyrrolidinopyridine (PPY) and 2,5-diphenyloxazole (DPO) were employed as N-heterocyclic derivatives to synthesize novel picrate salts. These salts were subsequently subjected to characterization using infrared spectroscopy, ultraviolet spectroscopy, and single-crystal X-ray diffraction. Comparison of these structures with entries in the Cambridge Structural Database (CSD) and the application of two multivariate statistical analyses, namely Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA), facilitated the differentiation of salts and co-crystals based on the structural behaviors of the picrate molecule. Additionally, Hirshfield Surface Analysis and 2D fingerprint plots were employed to investigate intermolecular contacts. The fluorescence emission spectra revealed that compound 2 has the potential to serve as a probe for turn-off detection of picric acid (PA).