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Crystal Environment Induced Symmetry Reduction (CEISR): Deep Analysis Of Para-chloroacetophenone Azine And Generalization
CrystEngComm
  • Harmeet Bhoday
  • Kaidi Yang
  • Steven P. Kelley
  • Rainer Glaser, Missouri University of Science and Technology
Abstract

The morphologies of sixteen crystal structures of ten symmetrical Xpara-Ph-(Me)C 00000000 00000000 00000000 00000000 11111111 = N-N = C (Me)-Ph-Xpara azines: 1 (Cl), 2 (Br), 3 (I), 4 (OH), 5 (PhO), 6 (CF3), 7 (F), 8 (Me), 9 (NO2), and 10 (PrO) are described. All the azines crystallize forming idioteloamphiphile monolayers (IAMs) and their morphologies fall into the two main classes of "flat" and "shiplap" depending on the lateral offsets between next neighbors in the monolayer. Ab initio studies show that the (E,E)-configured p-disubstituted acetophenone azines are C2-symmetric in the gas phase and that the azine and phenyl twists are correlated and give rise to P- and M-chirality. The crystal structures of 1-10 are true racemates and, remarkably, the majority feature asymmetric (C1) azines rather than dissymmetric (C2) azines. To understand the origin of the symmetry reduction, we studied the supramolecular structures and IAM characteristics of the five azines that crystallize with a flat morphology 1-I (Cl), 2-Ia (Br), 3 (I), 5 (PhO), and 10 (PrO). The deep analysis of chloroazine 1-I shows that the symmetry reduction is the result of qualitatively different coordination environments of the two chloroarene moieties and presents a case of crystal environment induced symmetry reduction (CEISR). The crystal structure of 1-I is of the type "AABB Kick/Flat" and the advantages of the double-stripe motif are explained. Careful analysis of the crystal structure showed arene-arene T-contacts of the types edge-to-face (e|f), face-to-edge (f|e), and face-to-face (f|f), a new arene-azine interaction (e|Az), and H⋯Cl, Cl⋯π, and Cl⋯Cl contacts. Intra- and interlayer interaction inventory analyses show in a compelling fashion that the arenes Ai and As in each azine engage in qualitatively different intermolecular interactions. To demonstrate the usefulness of the interaction inventory analysis, we also compare and contrast the crystal environments of the C1-symmetric azines in crystals of 2-Ia (Br) and 10 (PrO) and the C2-symmetric azines in crystals of 3 (I) and 5 (PhO). Intermolecular interactions are quantified using Hirshfeld surface analyses, pairwise interaction energies, and electrostatic potential maps. We will also describe a fast method for the detection of CEISR based on N⋯H Hirshfeld 2D fingerprint plots.

Department(s)
Chemistry
Comments

National Science Foundation, Grant 1665487

Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2023 Royal Society of Chemistry, All rights reserved.
Publication Date
8-10-2023
Publication Date
10 Aug 2023
Disciplines
Citation Information
Harmeet Bhoday, Kaidi Yang, Steven P. Kelley and Rainer Glaser. "Crystal Environment Induced Symmetry Reduction (CEISR): Deep Analysis Of Para-chloroacetophenone Azine And Generalization" CrystEngComm Vol. 25 Iss. 33 (2023) p. 4638 - 4657 ISSN: 1466-8033
Available at: http://works.bepress.com/rainer-glaser/170/