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In this study, the precise positioning and alignment of arrays of two different guest molecules in a crystalline host matrix has been engineered and resulted in new optically active materials. Sub‐nm differences in the diameters of two types of 1D channels are sufficient for size‐selective inclusion of dyes. Energy transport occurs between the arrays of different dyes that are included in parallel‐positioned nanochannels by Förster resonance energy transfer (FRET). The color of individual micro‐sized crystals are dependent on their relative position under polarized light. This angular‐dependent behavior is a result of the geometrically constrained orientation of the dyes by the crystallographic packing of the host matrix and is concentration dependent. [ABSTRACT FROM AUTHOR]

We demonstrate here a unique metallo‐organic material where the appearance and the internal crystal structure are in contradiction. The egg‐shaped (ovoid) crystals have a brain‐like texture. Although these micro‐sized crystals are monodispersed; like fingerprints their grainy surfaces are never exactly alike. Remarkably, our X‐ray and electron diffraction studies unexpectedly revealed that these structures are single‐crystals comprising a continuous coordination network of two differently shaped homochiral channels. By using the same building blocks under different reaction conditions, a rare series of crystals have been obtained that are uniquely rounded in their shape. In stark contrast to the brain‐like crystals, these isostructural and monodispersed crystals have a comparatively smooth appearance. The sizes of these crystals vary by several orders of magnitude. [ABSTRACT FROM AUTHOR]

Enabling and understanding new methodologies to fabricate molecular assemblies driven by intermolecular interactions is fundamental in chemistry. Such forces can be used to control crystal growth and enable surface-confinement of these materials, which remains challenging. Here we demonstrate for the first time, a solvent-free on-surface crystal-to-co-crystal conversion process driven by halogen bonding (XB). By exposing a polycrystalline organic material, consisting of a XB-acceptor moiety, to the vapors of a complementary XB-donor compound, the corresponding halogen-bonded co-crystals were formed. Furthermore, we demonstrate that this approach can also be utilized for non-crystalline materials to afford surface-confined organic composites. Our stepwise vapor-based approach offers a new strategy for the formation of hybrid supramolecular materials. [ABSTRACT FROM AUTHOR]

The article reports on the assembly of crystalline halogen-bonded materials by physical vapor deposition (PVD). The authors report that the crystalline assemblies of 1 and 2, fabricated by PVD, exhibit controllable film morphologies. The authors state that halogen-bonded thin films may evolve into high quality functional materials.