S···π, π–π, and C–H···π Contacts Regulate Solid State Fluorescence in Regioisomeric Bisthiazolylpyrenes
作者:Shinaj K. Rajagopal、P. S. Salini、Mahesh Hariharan
DOI:10.1021/acs.cgd.6b00676
日期:2016.8.3
due to extensive π–π interactions, observed S···π interactions led to herringbone packing in 2′TP. The diverse packing arrangement of 2-2″TP led to a notable difference in the fluorescence behavior in the crystalline state. 2′TP possessing S···π interaction showed remarkable enhanced emission in the crystalline state compared to the amorphous state, in contrast to 2TP and 2″TP. Our results provide
HARVEY, R. G.;KONIECZNY, M.;PATAKI, J., J. ORG. CHEM., 1983, 48, N 17, 2930-2932
作者:HARVEY, R. G.、KONIECZNY, M.、PATAKI, J.
DOI:——
日期:——
Haloacetylation-Driven Transformation of Sandwich Herringbone to Lamellar/Columnar Packing in Pyrene
作者:P. S. Salini、Shinaj K. Rajagopal、Mahesh Hariharan
DOI:10.1021/acs.cgd.6b00919
日期:2016.10.5
Pyrene-based materials possessing one-dimensional cofacial π–π stacked structural motifs with short interplanar distances can have favorable charge transport properties. In this work, we have realized the switching of sandwich herringbone to lamellar/columnar arrangement by introducing α-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 dimensions. 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).