Versatile structures of group 13 metal halide complexes with 4,4′-bipy: from 1D coordination polymers to 2D and 3D metal–organic frameworks

The nature of the group 13 metal halides strongly affects the structure of their complexes with 4,4′-bipy.

Designed synthesis of a series of zwitterion–polyoxometalate hybrid materials for selective scavenging and photolysis of dyes

An effective strategy to immobilize both zwitterion and POM moieties into porous hybrid materials was developed. These materials demonstrate remarkable efficiency for selective scavenging and photolysis of cationic dyes from polluted water.

Syntheses, topological structures and properties of six metal–organic frameworks constructed from a flexible tetracarboxylate ligand

Six new metal–organic frameworks (MOFs), Co₂O(odip)(py)₂(DMSO)₂·3H₂O (1), Co₂(odip)(H₂O)(DMA)₂·2DMA (2), Co₄(odip)₂(H₂O)₄(DMSO)₂·5DMSO (3), [Zn₂(odip)(DMF)₂(H₂O)]·2DMF·2H₂O (4), Zn₂(odip)(H₂O) (5) and In(odip)·3ACN (6), have been synthesized from the 5,5′-oxydiisophthalic acid (H₄odip) ligand under solvothermal conditions.

High-symmetry embeddings of interpenetrating periodic nets. Essential rings and patterns of catenation

Symmetrical embeddings are given for multiply intergrown sets of some commonly occurring nets such asdia(diamond),qtz(quartz),pcu(net of primitive cubic lattice) andsrs(labyrinth net of theGminimal surface). Data are also given for all known pairs of nets which have edge-transitive self-dual tilings. Examples are given for symmetrical polycatenation of the 2-periodic netssql(square lattice) andhcb(honeycomb). The idea that the rings that are the faces of natural tilings form a complete basis set (essential rings) is explored and patterns of catenation of such rings described.

Periodic tiling of triangular and square nanotubes in a cationic metal–organic framework for selective anion exchange

A unique cationic metal–organic framework formed by connecting the neutral chain-like secondary building units with positively charged ligands shows charge- and size-dependent ion-exchange of anion dyes.

Coordination polymers constructed from a tripodal phosphoryl carboxylate ligand: synthesis, structures and physical properties

Four coordination polymers based on a new tripodal phosphoryl carboxylate H₃TBPPO ligand have been constructed and characterized. Complexes 1–3 show 2-fold interpenetrating flu net, while complex 4 possesses a 4-fold interpenetrating dia network.

Asymmetric induction in homochiral MOFs: from interweaving double helices to single helices

A pair of homochiral metal–organic frameworks with interweaving double helices from enantiopure ligands and single helices braided by 4,4′-bipyridine and cadmium clusters have been synthesized successfully as a result of asymmetric induction.

Constructing calixarene-supported high nuclearity Co27, Co28 and Ni18Na6 clusters with triazoles as co-bridges

Four high nuclearity compounds are constructed by M₄-calixarene SBUs and triazole co-bridges.

Metal–organic frameworks for luminescence thermometry

We describe the recent progress made in luminescent MOF thermometers, and especially highlight the development of dual-emitting ratiometric thermometers.

Ionic liquid directed syntheses of water-stable Eu– and Tb–organic-frameworks for aqueous-phase detection of nitroaromatic explosives

Ionic liquid directed syntheses of water-stable Eu– and Tb–organic-frameworks for aqueous-phase detection of nitroaromatic explosives.

Tuning oxygen-sensing behaviour of a porous coordination framework by a guest fluorophore

A new oxygen-sensing material with desirable excitation/emission characteristics was achieved by using a simple guest fluorophore.

Chiral template induced homochiral MOFs built from achiral components: SHG enhancement and enantioselective sensing of chiral alkamines by ion-exchange

A homochiral anionic framework built from achiral components was synthesized for enantioselective sensing of chiral alkamines. Ion-exchange with polar or chiral organic cations leads to the enhancement of the SHG efficiency.

Porous anionic indium-organic framework with enhanced gas and vapor adsorption and separation ability

A three-dimensional microporous anionic metal-organic framework (MOF) (Et4N)3[In3(TATB)4] (FJI-C1, H3TATB=4,4',4''-s-triazine-2,4,6-triyltribenzoic acid) with large unit cell volume has been synthesized. Assisted by the organic cation group Et4N in the pores of the compound, FJI-C1 not only shows high adsorption uptakes of C2 and C3 hydrocarbons, but also exhibits highly selective separation of propane, acetylene, ethane, and ethylene from methane at room temperature. Furthermore, it also exhibits high separation selectivity for propane over C2 hydrocarbons and acetylene can be readily separated from their C2 hydrocarbons mixtures at low pressure due to the high selectivity for C2H2 in comparison to C2H4 and C2H6. In addition, FJI-C1 with hydrophilic internal pores surfaces shows highly efficient adsorption separation of polar molecules from nonpolar molecules. Notably, it exhibits high separation selectivity for benzene over cyclohexane due to the π-π interactions between benzene molecules and s-triazine rings of the porous MOF.

Preparation, photophysical characterization, and modeling of LDS722/Laponite 2D-ordered hybrid films

A novel hybrid material with promising optical properties for nonlinear optical applications is presented, as formed by LDS 722 organic dye confined in Laponite clay. Thin films of the hybrid material with different dye loadings have been prepared. The film thickness, the dye and water content, and the clay swelling due to guest molecule incorporation have been characterized. Then, the photophysical properties of the thin films have been studied in detail using experimental methods and molecular simulation. As the dye load increases, the hybrid films present a hypsochromic shift in absorption and a bathochromic shift in emission. The former is attributed to the increasing strength of solvation of the dye donor group, while the latter is ascribed to a switch from an intramolecular to an intermolecular charge-transfer process as the dye load increases. The LDS 722 molecules are preferentially oriented in the host clay almost in parallel to the platelet surfaces, inducing macroscopic order that makes the material responsive to polarized light.

Confinement of pyridinium hemicyanine dye within an anionic metal-organic framework for two-photon-pumped lasing

Two-photon-pumped dye lasers are very important because of their applications in wavelength up-conversion, optical data storage, biological imaging and photodynamic therapy. Such lasers are very difficult to realize in the solid state because of the aggregation-caused quenching. Here we demonstrate a new two-photon-pumped micro-laser by encapsulating the cationic pyridinium hemicyanine dye into an anionic metal-organic framework (MOF). The resultant MOF⊃dye composite exhibits significant two-photon fluorescence because of the large absorption cross-section and the encapsulation-enhanced luminescent efficiency of the dye. Furthermore, the well-faceted MOF crystal serves as a natural Fabry–Perot resonance cavity, leading to lasing around 640 nm when pumped with a 1064-nm pulse laser. This strategy not only combines the crystalline benefit of MOFs and luminescent behaviour of organic dyes but also creates a new synergistic two-photon-pumped lasing functionality, opening a new avenue for the future creation of solid-state photonic materials and devices.

Two-photon-pumped dye lasers are useful for applications such as biological imaging; however, loss processes reduce their efficiency. Here, metal-organic frameworks, into which the laser dye is incorporated, demonstrate enhanced laser operation because losses such as dye aggregation-caused quenching are reduced.

Substitution reactions in metal–organic frameworks and metal–organic polyhedra

This review summarizes the advances in the study of substitution reactions in metal–organic frameworks (MOFs) and metal–organic polyhedra (MOPs).

Encapsulation of large dye molecules in hierarchically superstructured metal–organic frameworks

A perturbation assisted nanofusion technique to construct hierarchically superstructured MOFs was reported. In particular, the mesopores in the MOF structure enabled the confinement of large dye species, resulting in fluorescent dye@MOF composite materials.

Coligand-directed synthesis of five Co(ii)/Ni(ii) coordination polymers with a neutral tetradentate ligand: syntheses, crystal structures, and properties

The solvothermal reactions afforded five coordination polymers with different coligands, and the coligand-directed synthesis has a great effect on the final structures.

Post-synthetic metalation of metal–organic frameworks

Post-synthetic metalation (PSMet) offers expansive scope for a targeted approach to tailoring the properties of MOFs.

Anion-templated assembly of three indium–organic frameworks with diverse topologies

Three novel In-MOFs with ung, crb and cbo networks based on the H₂bpydc ligand have been prepared under solvothermal conditions. Structural analyses reveal that these three compounds possess monomeric indium inorganic building units and they are obtained using different anion templates such as NO₃⁻, HCOO⁻ and Cl⁻.

A bimodal anionic MOF: turn-off sensing of CuII and specific sensitization of EuIII

A bimodal anionic MOF is reported which acts as a turn-off Cu^II sensor as well as a specific Eu^III sensitizer via cation exchange.

A ratiometric and colorimetric luminescent thermometer over a wide temperature range based on a lanthanide coordination polymer

A lanthanide coordination polymer Tb0.957Eu0.043cpda was synthesized as a ratiometric and colorimetric luminescent thermometer. The high triplet excited state energy of a linker enables Tb0.957Eu0.043cpda to detect and visualize temperature over a wide range from cryogenic to room temperature (40-300 K).

Tunable porous organic crystals: structural scope and adsorption properties of nanoporous steroidal ureas

Previous work has shown that certain steroidal bis-(N-phenyl)ureas, derived from cholic acid, form crystals in the P6(1) space group with unusually wide unidimensional pores. A key feature of the nanoporous steroidal urea (NPSU) structure is that groups at either end of the steroid are directed into the channels and may in principle be altered without disturbing the crystal packing. Herein we report an expanded study of this system, which increases the structural variety of NPSUs and also examines their inclusion properties. Nineteen new NPSU crystal structures are described, to add to the six which were previously reported. The materials show wide variations in channel size, shape, and chemical nature. Minimum pore diameters vary from ~0 up to 13.1 Å, while some of the interior surfaces are markedly corrugated. Several variants possess functional groups positioned in the channels with potential to interact with guest molecules. Inclusion studies were performed using a relatively accessible tris-(N-phenyl)urea. Solvent removal was possible without crystal degradation, and gas adsorption could be demonstrated. Organic molecules ranging from simple aromatics (e.g., aniline and chlorobenzene) to the much larger squalene (M(w) = 411) could be adsorbed from the liquid state, while several dyes were taken up from solutions in ether. Some dyes gave dichroic complexes, implying alignment of the chromophores in the NPSU channels. Notably, these complexes were formed by direct adsorption rather than cocrystallization, emphasizing the unusually robust nature of these organic molecular hosts.

Nets with collisions (unstable nets) and crystal chemistry

Nets in which different vertices have identical barycentric coordinates (i.e.have collisions) are called unstable. Some such nets have automorphisms that do not correspond to crystallographic symmetries and are called non-crystallographic. Examples are given of nets taken from real crystal structures which have embeddings with crystallographic symmetry in which colliding nodes either are, or are not, topological neighbors (linked) and in which some links coincide. An example is also given of a crystallographic net of exceptional girth (16), which has collisions in barycentric coordinates but which also has embeddings without collisions with the same symmetry. In this last case the collisions are termedunforced.