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−H···O and C−H···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−H···X (X = N/O) hydrogen bonding appears to significantly influence
supramolecular isomerism in this system.