Metal–organic frameworks (MOFs) or porous coordination polymers (PCPs) are open, crystalline supramolecular coordination architectures with porous facets. These chemically tailorable framework materials are the subject of intense and expansive research, and are particularly relevant in the fields of sensory materials and device engineering. As the subfield of MOF-based sensing has developed, many diverse chemical functionalities have been carefully and rationally implanted into the coordination nanospace of MOF materials. MOFs with widely varied fluorometric sensing properties have been developed using the design principles of crystal engineering and structure–property correlations, resulting in a large and rapidly growing body of literature. This work has led to advancements in a number of crucial sensing domains, including biomolecules, environmental toxins, explosives, ionic species, and many others. Furthermore, new classes of MOF sensory materials utilizing advanced signal transduction by devices based on MOF photonic crystals and thin films have been developed. This comprehensive review summarizes the topical developments in the field of luminescent MOF and MOF-based photonic crystals/thin film sensory materials.

Metal-organic frameworks: functional luminescent and photonic materials for sensing applications.

Atomically precise pieces of matter of nanometer dimensions composed of noble metals are new categories of materials with many unusual properties. Over 100 molecules of this kind with formulas such as Au25(SR)18, Au38(SR)24, and Au102(SR)44 as well as Ag25(SR)18, Ag29(S2R)12, and Ag44(SR)30 (often with a few counterions to compensate charges) are known now. They can be made reproducibly with robust synthetic protocols, resulting in colored solutions, yielding powders or diffractable crystals. They are distinctly different from nanoparticles in their spectroscopic properties such as optical absorption and emission, showing well-defined features, just like molecules. They show isotopically resolved molecular ion peaks in mass spectra and provide diverse information when examined through multiple instrumental methods. Most important of these properties is luminescence, often in the visible–near-infrared window, useful in biological applications. Luminescence in the visible region, especially by clusters prot...

Atomically Precise Clusters of Noble Metals: Emerging Link between Atoms and Nanoparticles

Light-Emitting Self-Assembled Materials Based on d(8) and d(10) Transition Metal Complexes.

Luminescent sensors based on metal-organic frameworks

The recent advancement of water stable metal–organic frameworks (MOFs) expands the application of this unique porous material. This review article aims at studying their applications in terms of five major areas: adsorption, membrane separation, sensing, catalysis, and proton conduction. These applications are either conducted in a water-containing environment or directly targeted on water treatment processes. The representative and significant studies in each area were comprehensively reviewed and discussed for perspectives, to serve as a reference for researchers working in related areas. At the end, a summary and future outlook on the applications of water stable MOFs are suggested as concluding remarks.

Applications of water stable metal–organic frameworks

Five new MnII coordination polymers, namely [Mn2(tbip)2(bix)] (1), [Mn3(tbip)3(bix)2] (2), [Mn3(tbip)2(Htbip)2(bib)2]·4H2O (3), [Mn4(tbip)4(bbp)2(H2O)2] (4), and [Mn4(tbip)4(bip)]·2H2O (5), were prepared by hydrothermal reactions of Mn(II) acetate with H2tbip (5-tert-butyl isophthalic acid) in the presence of different di-imidazolyl coligands (bix =1,4-bis(imidazol-1-ylmethyl)benzene, bib =1,4-bis(imidazol) butane, bbp =1,3-bis(benzimidazol)propane, bip =1,3-bis(imidazol)propane). All complexes were characterized by elemental analysis, IR spectra, thermogravimetric analysis, single-crystal X-ray crystallography, and powder X-ray diffraction. Single crystal X-ray studies show that these coordination polymers contain homometallic clusters varying from dimeric, trimeric, and tetrameric motifs to polymeric chains depending upon the coligands used. Complex 1 has a 3D 6-connected polycatenane network with dinuclear [Mn2O2] secondary building units. Complex 2 possesses a 3D 8-connected structure with trinuclear ...

MnII Coordination Polymers Based on Bi-, Tri-, and Tetranuclear and Polymeric Chain Building Units: Crystal Structures and Magnetic Properties

Spatial confinement of a cationic MOF: a SC–SC approach for high capacity Cr(VI)-oxyanion capture in aqueous solution

A water-stable fluorescent microporous metal–organic framework (MOF), [Tb(L)(OH)]·x(solv) (1), has been designed and successfully synthesized under a combination of hydro/solvothermal and ionothermal conditions (H2L = 5-(4-carboxyphenyl)pyridine-2-carboxylate). The crystal structure reveals that complex 1 consists of cubane-shaped tetranuclear terbium building units, which are further bridged by the multicarboxylate ligands to give a (3,12)-connected topology with the point symbol (420·628·818)(43)4. More importantly, the excellent hydrolytic stability allows it to be used in an aquatic system, which is highly desirable for practical applications. Activated 1 shows high selectivity and sensitivity towards nitroaromatic explosives in both aqueous and vapor phases. The sizes of the pore windows (11.2 × 11.2 A2) in 1, which are larger than the sizes of the selected nitroaromatics, could permit easy diffusion of analytes inside the channel, keeping the electron rich framework and electron deficient analytes in close proximity.

Aqueous- and vapor-phase detection of nitroaromatic explosives by a water-stable fluorescent microporous MOF directed by an ionic liquid

Highly dense packing of chromophoric linkers is achieved in a novel pyrene-based metal-organic framework (MOF), [Zn(TBAPy)1/2(H2O)2], induced by an ionic liquid. This MOF displays a quick response to visible-light irradiation (photocurrent density of up to 4.492 μA cm-2) and is capable of repetitive on-off photocurrent switching with a large on-off ratio (37.55).

Highly Dense Packing of Chromophoric Linkers Achievable in a Pyrene-Based Metal–Organic Framework for Photoelectric Response

A novel discrete open high-nuclearity nest-like silver thiolate cluster complex, [Ag33 S3 (StBu)16 (CF3 COO)9 (NO3 )(CH3 CN)2 ](NO3 ) (1), has been isolated with nitrate and S(2-) anions acting as structure-directing templates Its similar nest-like structure has been assembled into an extended layer [Ag31 S3 (StBu)16 (NO3 )9 ]n (2) by adjustment of auxiliary ligand More interestingly, both complexes exhibit temperature-dependent luminescence of high sensitivity with a large fluorescence enhancement (12-fold for 1, 21-fold for 2), which can be easily recognized by the naked-eye (dramatic red-shift Δ=104 nm for 1, larger Δ=113 nm for 2 at 77 K compared to those at 298 K) The correlation between luminescent thermochromism and temperature-dependent variation of the coordination modes of template NO3 (-) anion, Ag⋅⋅⋅S and Ag⋅⋅⋅Ag distances are also elucidated through variable-temperature single-crystal X-ray crystal structure (VT-SCXRD) analyses

Jian-Hua Qin

Papers

MnII Coordination Polymers Based on Bi-, Tri-, and Tetranuclear and Polymeric Chain Building Units: Crystal Structures and Magnetic Properties

Spatial confinement of a cationic MOF: a SC–SC approach for high capacity Cr(VI)-oxyanion capture in aqueous solution

Aqueous- and vapor-phase detection of nitroaromatic explosives by a water-stable fluorescent microporous MOF directed by an ionic liquid

Highly Dense Packing of Chromophoric Linkers Achievable in a Pyrene-Based Metal–Organic Framework for Photoelectric Response

Thermochromic Luminescent Nest‐Like Silver Thiolate Cluster