Polymorphism and pseudopolymorphism in the triaroylbenzene derivative 1,3,5-tris(4-cyanobenzoyl)benzene

The triaroylbenzene derivative 1,3,5-tris(4-cyanobenzoyl)benzene exhibits the phenomenon of concomitant polymorphism. Two topologically isomeric solid-state networks, hexagonal and ladder, were obtained upon crystallization from acetone/water solution. In contrast, crystallization of the title compound from EtOAc, 3-pentanone, MeNO2, DMSO, acetone, and methyl chloroacetate produced isostructural pseudopolymorphic inclusion complexes. In all these six cases, the triaroylbenzene host molecule self-assembles in a 2D lamellar pattern via C-(HO)-O-... and C-(HN)-N-... hydrogen bonding with guest solvent molecules residing in interlayer channels. A clathrate of different morphology was obtained upon crystallization from nitroethane. In all seven inclusion adducts, bifurcated C-H...O hydrogen bonding between host donors and the guest acceptors was observed as a common feature. The network topologies in the polymorphic modifications of 1 are different from those observed in the structurally characterized inclusion complexes. Thus, C-(HX)-X-... (X = N/O) hydrogen bonding appears to significantly influence supramolecular isomerism in this system.