Haloacetylation-Driven Transformation of Sandwich Herringbone to Lamellar/Columnar Packing in Pyrene

Abstract

Pyrene based materials possessing one dimensional co-facial π-π stacked structural motif with short interplanar distance can have favorable charge transport properties. In this work, we have realized the switching of sandwich herringbone to lamellar/columnar arrangement by introducing ∝-haloacetyl substituents in pyrene. Density functional theory calculations showed that the subtle difference in the charge distribution induced by the haloacetyl group plays an important role in regulating the cofacial stacking. Single crystal X-ray structural analyses and quantum theory of atoms in molecules (QTAIM) analyses revealed the role of dihydrogen contacts, halogen interactions and hydrogen bonding in extending the columnar/lamellar arrangement in three dimension. Hirshfeld surface analyses showed γ (lamellar) and β (columnar) packing motifs indicating extensive π-π stacking interaction between pyrene units. Detailed structural analysis revealed a gradual decrease in the intermolecular π-π stacking distance (dπ-π = 3.39 Å) with increasing the polarizability of halogen atom, a characteristic interplanar distance observed in highly oriented pyrolytic graphite (dπ-π; 3.35-3.39 Å).