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.

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The upbuilding of dirhodium tetracarboxylate paddlewheels into porous architectures is still challenging because of the inertness of equatorial carboxylates for ligand-exchange reaction. Here we demonstrate the synthesis of a new family of metal-organic cuboctahedra by connecting dirhodium units through 1,3-benzenedicarboxylate and assembling cuboctahedra as porous solids. Carbon monoxide and nitric oxide were strongly trapped in the internal cavity thanks to the strong affinity of unsaturated axial coordination sites of dirhodium centers.

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A novel organic-inorganic hybrid based on cystamine and BiI5chains is prepared. Due to the flexibility of the disulfide molecules in the structure, single crystals or crystalline thin films of this hybrid undergo a reversible acentric-to-centric structural transition at moderate conditions (T = 36.8 °C). This makes the title compound an excellent candidate for temperature controlled SHG or THG switches.

Syntheses, X-ray structural characterization, optical properties, and electronic structures of 1D metal(III) iodide hybrids, namely, alpha-((CH(3))(2)S(CH(2))(2)NH(3))BiI(5) (1a), beta-((CH(3))(2)S(CH(2))(2)NH(3))BiI(5) (1b), ((CH(3))(2)S(CH(2))(2)NH(3))SbI(5) (2), and (HO(2)C(C(6)H(4))CH(2)NH(3))BiI(4) (3), are reported. According to the results of single-crystal X-ray diffraction analyses, the 1D inorganic chains are constructed by corner-shared M(III)I(6) octahedra in 1a, 1b, and 2 and by edge-shared ones in 3. In polymorphs 1a, 1b, and 2, the polymeric BiI(5)(2-) anionic chains are charge-balanced by the dimethyl(2-ethylammonium)sulfonium (dmes) dications. Complex 1a crystallizes in the polar space group of P2(1)cn. A spectacular umbrella reversal of half sulfonium parts together with the conformational change of half polymeric anions in the crystal structure of 1a occurs at moderate temperature (73 degrees C), leading to the beta-phase 1b, through a reversible single-crystal-to-single-crystal process. Complex 1b, as well as the isotype structure of 2, crystallize in the nonpolar acentric space group of P2(1)2(1)2(1). Because of their acentric structural characteristic, second harmonic generation (SHG) optical properties are observed in the polycrystalline powder samples of 1a, 1b, and 2. It is notable that the SHG signal of 1a is much stronger than that of 1b and 2 owing to the polarity of 1a. Remarkably, the peculiar dissymmetrical dication of dmes is able to modify the bonding features of the inorganic frameworks through shortening I...I distances between adjacent chains (d(I...I) < 4A). The structure of 3, which crystallizes in the triclinic space group P1, features a polymeric anionic chain constructed from edge-shared BiI(6) octahedra. The charge is balanced by the pairs of trans-4-(ammoniummethyl)-cyclohexane-carboxylic acid, which are linked together via the H bonding between the carboxylic groups to form a pseudodication. The results of DFT calculations based on the structures of 1a and 3 indicate that the narrower band gap in 1 appears to be associated on the one hand with a sigma* I-p/Bi-s interaction that moves the Fermi level to higher energy and on the other hand with the interchain I...I contacts.