We report the preparation and crystal structure of a triply stacked metal complex array in which a Cu-phthalocyanine is sandwiched between different Cu-porphyrins. The discrete heterogeneous assembly was prepared through formation of a fourfold rotaxane from a tetradactyl porphyrin with alkylammonium moieties and a phthalocyanine bearing four crown ethers and the subsequent formation of an ionic complex between the fourfold rotaxane and a tetraanionic porphyrin. The tetraanionic porphyrin, Cu-TPPS(4-), is selectively bound to the fourfold rotaxane through cooperative π-π and ionic interactions. The crystal structure revealed the columnar stacked array of the three planar building components in a precise order and spatial arrangement that promote intermolecular electronic communication.

One-pot copper-catalyzed hydroallylation/lactone cyclization of γ-hydroxybutynoate derivatives was developed to afford β-allylbutenolides.

The flexibility of the bridging alkyl chains is important for proximity in the stacking of porphyrin and phthalocyanine conjugated through a fourfold rotaxane linkage. This picture shows a chochin, a Japanese lantern made with paper and thin strips of bamboo that can be expanded and contracted flexibly. This foldability recalls the induced molecular interaction in the flexible molecular conjugate. More information can be found in the Research Article by K. Tanaka et al. (DOI: 10.1002/chem.202200819).

Invited for the cover of this issue are Kentaro Tanaka at Nagoya University and co‐workers. The image depicts the importance of the flexibility of bridging alkyl chains in a molecular conjugate to pack the components closely to generate efficient molecular communication. Read the full text of the article at 10.1002/chem.202200819.

The efficiency of the hydroallylation step depends on the environment around the (protected) alcohol moiety.