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Angewandte Chemie International Edition, Volume 51, Issue 48, pages 12012–12015, November 26, 2012.
Sandipan Roy, Dr. Suvra Prakash Mondal, Prof. Samit K. Ray,Prof. Kumar Biradha.
Department of Chemistry, Indian Institute of Technology, Kharagpur-721302 (India).
Department of Physics, Indian Institute of Technology, Kharagpur-721302 (India).
Abstract
More than the sum of the parts: The property of a supramolecular material can differ significantly from those of the constituent materials. Two organic components, which are nonconductive, nonphotochromic, and nonluminescent, were shown to self-assemble by cation–π, π–π, and carboxylate–pyridinium interactions. An organic semiconductor is thus produced with significant charge mobility and photochromic and photoluminescence properties.
Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Additional Information
The assembly of two di-cations and two di-anions (tetrameric aggregate) formed via cation-p interactions between the two pyridinium rings and -COO–…H-N+ charge assisted hydrogen bonds between carboxylate (donor)–pyridinium (acceptor) groups. These interactions within the aggregate and cross-conjugation in the pentadienone moiety resulted in the formation of free electrons upon irradiation which is being reflected as photchormism in the crystals (yellow to green). The presence of free electrons in the green crystals lead to the greater conducting and photoluminescence properties that can be switched on and off by the cycles of irradiation and heating. Further, decay studies clearly demonstrate that the irradiated crystals (IR) have longer lifetime compared to non-irradiated ones (NR).
