Flexible porous coordination polymers change their structure in response to molecular incorporation but recover their original configuration after the guest has been removed. We demonstrated that the crystal downsizing of twofold interpenetrated frameworks of [Cu(2)(dicarboxylate)(2)(amine)](n) regulates the structural flexibility and induces a shape-memory effect in the coordination frameworks. In addition to the two structures that contribute to the sorption process (that is, a nonporous closed phase and a guest-included open phase), we isolated an unusual, metastable open dried phase when downsizing the crystals to the mesoscale, and the closed phase was recovered by thermal treatment. Crystal downsizing suppressed the structural mobility and stabilized the open dried phase. The successful isolation of two interconvertible empty phases, the closed phase and the open dried phase, provided switchable sorption properties with or without gate-opening behavior.

The spatial organization of porous coordination polymer (PCP) crystals into higher-order structures is critical for their integration into separation systems, heterogeneous catalysts, ion/electron transport and photonic devices. Here, we demonstrate a rapid method to spatially control the nucleation site, leading to the formation of mesoscopic architecture made of PCPs, in both two and three dimensions. Inspired by geological processes, this method relies on the morphological replacement of a shaped sacrificial metal oxide used both as a metal source and as an 'architecture-directing agent' by an analogous PCP architecture. Spatiotemporal harmonization of the metal oxide dissolution and the PCP crystallization allowed the preservation of very fine mineral morphological details of periodic alumina inverse opal structures. The replication of randomly structured alumina aerogels resulted in a PCP architecture with hierarchical porosity in which the hydrophobic micropores of the PCP and the mesopores/macropores inherited from the parent aerogels synergistically enhanced the material's selectivity and mass transfer for water/ethanol separation.

Undistorted perovskite layers are formed in PbI4-based hybrid perovskites incorporating X−(CH2)2−NH3 + (X = Br, Cl) cations. The outstanding structural feature of these compounds is the result of halogen and hydrogen bonding at the organic−inorganic interface, leading to the absence of hydrogen bonds between equatorial iodine atoms of the perovskite layer and ammonium parts, these last being located out of perovskite layers. As a consequence, these red salts display a reduced band gap (2.2 eV) which is assigned to a more disperse HOMO band compared to other salts such as (I−(CH2)2−NH3)2PbI4.