title: A heuristic approach to evaluateperiinteractionsversusintermolecular interactions in an overcrowded naphthalene.
abstract: Octachloronaphthalene (OCN), a serious environmental pollutant, has been investigated by charge density analysis to unravel several unexplored factors responsible for steric overcrowding. The topological features of the enigmaticperiinteractions contributing to steric overcrowding are qualified and quantified from experimental and theoretical charge-density studies. A new facet in the fundamental understanding ofperiinteractions is revealed by NCI (non-covalent interaction) analysis. The potential role of these interactions in deforming the molecular geometry and subsequent effect on aromaticity are substantiated from NICS (Nuclear Independent Chemical Shift) and QTAIM (Quantum Theory of Atoms in Molecules) calculations. The eye-catching dissimilarity in the out-of-plane twisting of OCN renders the molecule in an asymmetric geometry in the crystalline phase compared with symmetric geometry in the optimized solvated phase. This is uniquely characterized by their molecular electrostatic potential (MESP), respectively, and is explained in terms of conflict between two opposing forces -periinteractions, and symbiotic intermolecular Cl⋯Cl and Cl⋯π contacts.
authors.affiliation: Solid State and Structural Chemistry Unit, Indian Institute of Science , C. V. Raman Avenue, Bangalore, Karnataka 560012, India.
authors.forename: Sounak
authors.identifier: https://orcid.org/0000-0002-1037-8045
authors.initials: S
authors.lastname: Sarkar
authors.affiliation: Solid State and Structural Chemistry Unit, Indian Institute of Science , C. V. Raman Avenue, Bangalore, Karnataka 560012, India.
authors.forename: Tayur N Guru
authors.initials: TN
authors.lastname: Row
keywords: aromaticity; charge density; charge spin and momentum densities; halogen bonding; intermolecular interactions; overcrowding; peri interaction