Combinatorial Enumeration of Isomers of Superaromatic Polysubstituted Cycloarenes and Coronoid Hydrocarbons with Applications to NMR

Abstract

We have employed combinatorial techniques based on character cycle indices, Pólya's theory, and Euler totem function to enumerate isomers of polysubstituted cycloarenes and coronoid hydrocarbons which have been receiving considerable attention because of their superaromaticity, ring currents, and interesting magnetic properties. Systematic enumeration and construction of tables of polysubstituted isomers such as fluoro-chloro superaromatic hydrocarbons are considered as they are of interest in the study of environmental pollutants and toxicity. Isomers of fluoro-chloro polysubstituted donut shaped circumkekulenes, circumseptulenes, circumoctulenes, etc., are enumerated in addition to other cycloarenes, polycyclic circumcoronaphenes and coronoids. Applications to C NMR, proton NMR and multiple quantum NMR spectroscopies of these superaromatic species are considered.

Review on Chemical Graph Theory and Its Application in Computer-Assisted Structure Elucidation

“…Then polynomial representation was constructed based on cycle indices. In the literature, isomer enumeration studies were mostly for special compound classes such as alkanes, aromatic hydrocarbons and polycyclic aromatic compounds (Bytautas and Klein 1998;Dias 1984;Balasubramanian 2018).…”

Topological Characterization and Graph Entropies of Tessellations of Kekulene Structures: Existence of Isentropic Structures and Applications to Thermochemistry, Nuclear Magnetic Resonance, and Electron Spin Resonance

“…They possess optimal cavities with desirable electronic features and pore sizes for trapping metal ions. A number of elegant combinatorial and graph-theoretical techniques have been proposed for computing the spectroscopic properties and stabilities of polycyclic aromatics and fullerenes such as the conjugated circuit method, aromatic sextets, topological resonance theories, ring currents, matching polynomials, and so on. − The first representative prototypical cycloarene is cyclo­[ d . e .…”

“…Various topological techniques that have been employed to study kekulene have revealed that their π electrons are delocalized within individual benzene rings rather than globally in an annulenoid fashion over the entire molecular framework . Such novel electronic features combined with their geometrical structures with pores offer a variety of intriguing possibilities for synthetic organic chemistry, environmental management, and rational drug design as these cycloarenes are potential candidates for both the trapping and transportation of drugs, metal ions, chloride anions, and so forth. − ,, …”

“…As demonstrated by Balasubramanian, , these advancements in exploring the vast spectrum of newly synthesized potential compounds require mathematical tools derived from graph theory, combinatorial mathematics, artificial intelligence, and group theory for the developments of structure–activity relations and spectroscopic characterizations. Predictive computational toxicology and drug discovery rely on techniques such as quantitative molecular similarity, quantitative structure–activity relations, and targeted therapeutic approaches that together yield more robust techniques for computer-aided drug discovery .…”

“…24 Such novel electronic features combined with their geometrical structures with pores offer a variety of intriguing possibilities for synthetic organic chemistry, environmental management, and rational drug design as these cycloarenes are potential candidates for both the trapping and transportation of drugs, metal ions, chloride anions, and so forth. [1][2][3]26,27 As demonstrated by Balasubramanian, 26,28 these advancements in exploring the vast spectrum of newly synthesized potential compounds require mathematical tools derived from graph theory, combinatorial mathematics, artificial intelligence, and group theory for the developments of structure−activity relations and spectroscopic characterizations. Predictive computational toxicology and drug discovery rely on techniques such as quantitative molecular similarity, quantitative structure−activity relations, and targeted therapeutic approaches that together yield more robust techniques for computer-aided drug discovery.…”