Two new cases of polymorphism in diagonally substituted rubrene derivatives

Abstract

The crystal structures of two rubrene derivatives, 5,11-diphenyl-6,12-bis[4-(trifluoromethyl)phenyl]tetracene, C44H26F6, and 5,11-bis(4-tert-butylphenyl)-6,12-diphenyltetracene, C50H44, are presented. Each are substituted on diagonal (5/11) phenyl rings. Each derivative has one polymorph reported previously. A discussion of the differences between each derivative and its previously reported polymorph is provided. The triclinic packing of the CF3-substituted structure is similar to the packing of the parent rubrene's triclinic polymorph. In the tert-butyl-substituted structure, a planar tetracene core formed, which has been hypothesized but never published. Crystallization conditions are provided as they differ from previous reports.

Keywords

• rubrene
• polymorphism
• crystal structure