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Abstract: Like other derivatives of hexaphenylbenzene, hexakis(4-nitrophenyl)benzene (1) crystallizes under a variety of conditions as layered structures in which significant quantities of guests are included in spaces between the layers or within them. In structures of nitroarene 1, multiple intermolecular N⋯O interactions of NO2 groups help to hold the layers together and determine how the molecular constituents are positioned. The behavior of nitroarene 1 confirms that N⋯O interactions can allow crystal engineers to position molecules with a useful degree of predictability, particularly when stronger interactions such as hydrogen bonds are absent, and when competition with other weak interactions is limited. [Copyright &y& Elsevier]

Hexakis[4-(2,4-diamino-1,3,5-triazin-6-yl)phenyl]benzene (4) incorporates a disc-shaped hexaphenylbenzene core and six peripheral diaminotriazine groups that can engage in hydrogen bonding according to established motifs. Under all conditions examined, compound 4 crystallizes as planned to give closely related noninterpenetrated three-dimensional networks built from sheets in which each molecule has six hydrogen-bonded neighbors. In the structure of compound 4, the number of hydrogen bonds per molecule and the percentage of volume accessible to guests approach the highest values so far observed in molecular networks. Analogue 5 (which has the same hexaphenylbenzene core but only four diaminotriazine groups at the 1,2,4,5-positions) and analogue 7 (in which the two unsubstituted phenyl groups of compound 5 are replaced by methyl groups) crystallize according to a closely similar pattern. Analogues with flatter pentaphenylbenzene or tetraphenylbenzene cores crystallize differently, underscoring the importance of maintaining a consistent molecular shape in attempts to engineer crystals with predetermined properties. [ABSTRACT FROM AUTHOR]

The title compound (systematic name: benzene-4,4′,4′′,4′′′,4′′′′,4′′′′′-­hexayl­hexa­benzo­nitrile dichloro­methane disolvate), C48H24N6·2CH2Cl2, crystallizes as an inclusion compound during the slow diffusion of methanol into a solution of hexa­kis(4-cyano­phenyl)­benzene in CH2Cl2. The hexa­kis(4-cyano­phenyl)benzene mol­ecule lies on an axis of twofold rotation in the space group Pbcn. Weak C—H⋯N inter­actions between hexa­kis(4-cyano­phenyl)benzene mol­ecules define an open network with space for including guests. The resulting structure is a new pseudopolymorph of hexa­kis(4-cyano­phenyl)benzene. The eight known pseudopolymorphs have few shared architectural features, in part because none of the inter­molecular inter­actions that are present plays a dominant role or forces neighboring mol­ecules to assume particular relative orientations. [ABSTRACT FROM AUTHOR]