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Updated: Jul 5, 2025

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
Published on: June 10, 2021
Insight into melting point differences of dinitroimidazoles and dinitropyrazoles from the perspective of
Junnan Wu1,2, Siwei Song3, Xiujuan Qi4
1School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang, 621010, China. yanghaijun@swust.edu.cn.
Abstract:
Dinitroimidazole (DNI) and dinitropyrazole (DNP), along with their congeners, possess similar molecular structures but exhibit distinct melting points. To analyse and elucidate the fundamental reasons for property differences from the perspective of intermolecular interactions, we proposed a simplified approach named binding energy in clusters (BEC) in computing weak interactions within complex crystal systems. Based on the results of the symmetry-adapted perturbation theory (SAPT) calculations, an approximate estimation of the melting point range can be derived by taking into account the cumulative effect (energy of electrostatic, dispersion and induction terms) and repulsive effect (energy of exchange term) values. We have also proposed a formula for calculating the specific melting point, which indicates that stronger intermolecular interactions have a major impact on the melting point, while the distribution of weak interactions also affects the melting point. This work would provide an effective reference for molecular design and structure-performance analysis.
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