Quantum Chemical Investigation of Polychlorinated Dibenzodioxins, Dibenzofurans and Biphenyls: Relative Stability and Planarity Analysis

Abstract

All the possible polychlorinated aromatic compounds in the classes of dibenzodioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) were studied by the quantum chemical methods of HF/6-311++G(d,p), B3LYP/6-311++G(d,p), and MP2/cc-pVTZ. The calculated stabilities and structures of these compounds were compared with the available data on their abundance and toxicity. Prediction models for trends in energy and planarity among these congeners were proposed. The results discussed here can help contribute to the understanding of the role of dioxin-like compounds (DLCs) in the environment.

Steric effects vs. electron delocalization: a new look into stability of diastereomers, conformers and constitutional Isomers

“…for the first few chlorine substitutions to polychlorinated biphenyls (PCB), polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), the most stable chlorination occurs at meta positions with respect to the other ring. 69 Figure 2 Unified models to predict the occurrence of preference for Z configuration, gauche conformation and meta isomer…”

Z-Matrix template-based substitution approach for enumeration of 3D molecular structures

“…For any number of substituents n, this method has a complexity of O(n 2 ). The number of tuples in finalist can be verified mathematically [11][12][13][14].…”

“…The approach has been used to study many classes of compounds from a simple and small class of molecules such as ethane and ethene to larger and more complex structures such as dioxin-like compounds [11][12][13][14][15]. The substitution scheme in the template can lead to different compounds of the same class, constitutional isomers, configurational isomers and conformational isomers.…”

“…Chemists, by their manual intuition and labour, have been able to identify template structures and substitution points for the combinatorial investigation of compounds. Inspired by the use of this approach in DDT analogues [5], we successfully applied it to 26 classes of compounds to exhaustively generate over ten thousand 3D structures for further investigation by quantum chemical methods [11][12][13][14][15]. Based on these previous reports, this is our first paper devoted to the methodology of generic structure generation using Z-matrix template-based substitution.…”

Steric vs Electronic Effects: A New Look into Stability of Diastereomers, Conformers and Constitutional Isomers

“…for the first few chlorine substitutions to polychlorinated biphenyls (PCB), polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), the most stable chlorination occurs at meta positions with respect to the other ring. 69…”