Directed Polymorphism and Mechanofluorochromism of Conjugated Materials through Weak Non-Covalent Control.

ABSTRACT: Understanding and manipulating crystal polymorphism can provide novel strategies for materials discovery in organic optoelectronics. In this paper, a series of seven ester-terminated three-ring phenylene ethynylenes (PEs) exhibit structure-dependent polymorphism wherein alkyl chain length modulates the propensity to form violet or green fluorescent solid phases, as well as tunable thermal and mechanofluorochromic (MFC) transitions. These compounds harness "soft" non-covalent control to achieve polymorphism: the electronic substituent effect of the ester groups weakens the fluoroarene-arene (ArF-ArH) interactions that typically direct crystal packing of this class of compounds, increasing competitiveness of other interactions. Small structural modifications tip this balance and shift the pr

SUBMITTER: Sharber SA 

PROVIDER: S-EPMC7597496 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature