Diversity in Mechanical Response in Donor–Acceptor Coupled Cocrystal Stoichiomorphs Based on Pyrene and 1,8-Dinitroanthraquinone Systems

• DOI: 10.1021/acs.cgd.8b00918
• Publication Date: 2018-09-28T20:15:27Z
• Authors: Manjeet Singh; Deepak Chopra
• Keywords: 01 natural sciences; 0104 chemical sciences; 3. Good health

Cocrystals are an emerging class of molecular materials that can achieve desirable properties by selecting suitable constituent molecules and can also exhibit polymorphism, but a different stoichiometry of the constituent molecular pairs can also give different structures having different properties, which is of interest. With an aim of understanding the influence of the stoichiometric ratio of the π-conjugated donor and acceptor in altering the crystal packing and their mechanical properties, we have synthesized two stoichiomorphs, namely, DQP1 (1A:1D) and DQP2 (1A:0.5D), along with their polymorphs, DQP3 (1A:2*0.5D) and DQP4 (2A:1D), respectively, involving pyrene as the donor (D) and 1,8-dinitroanthraquinone as an acceptor (A). Both stoichiomorphs have a layered structure with different packing patterns. DQP1 and DQP3 have −ADADAD– type, whereas DQP2 and DQP4 have −ADAADA– type of layered packing. DQP4 shows a thermosalient effect, and on heating converts into the polymorph DQP2 via single crystal to s...