We report a highly recyclable, 2D aromatic framework that offers a unique and versatile combination of photocatalytic activity and heavy metal uptake capability, as well as other attributes crucial for green and sustainable development technologies. The graphene-like open structure consists of fused tritopic aromatic building blocks (i.e., hexahydroxytriphenylene and hexaazatrinaphthylene) that can be assembled from readily available industrial materials without the need for transition metal catalysts. Besides fast and strong binding for Pb(II) ions (e.g., removing aqueous Pb ions below the drinkable limit within minutes), the alkaline N-heterocycle units of the robust and porous host are able to quantitatively catalyse Knoevenagel reactions in water. Furthermore, the fused donor–acceptor aromatic π-systems enable environmentally friendly photoredox catalysis (PRC) utilizing the safe and abundant visible light in a commercial flow reactor. Also discussed is a new metric for benchmarking the kinetic performance of sorbents in the context of heavy metal removal from drinking water.

The gyroid is an iconic structure that conjures up an intriguing 3D congener of the famous electronic systems of graphene and related 2D materials. Unlike the more accessible 2D graphitic systems, gyroidal metal–organic frameworks with demonstrated conductive properties remain unknown. We here report a semiconducting gyroidal net (denoted as HTT–Pb) that derives its rich electronic properties from the large organic π-electron system of a triphenylene core, highly polarizable Pb-dithiolene links, and robust Pb-oxo connections. In contrast to the generally encountered difficulty in crystallizing metal-thiolate networks, single crystals of HTT–Pb amenable to X-ray studies can be reliably obtained by regular solvothermal synthesis. The electronic conductivity of the framework solid is highly responsive to the water content in air, demonstrating potential use in chemiresistive sensing of humidity.

Carbon-coated binder-free flexible porous SnOx nanosheets (SnO/SnO2 heterogeneous structure) were fabricated and tested as anode materials for Na-ion batteries (NIBs). The novel free-standing and binder-free porous C@SnOx nanosheets were first self-assembled on a Cu substrate via a facile, low-cost anodization method followed by the carbonization treatment. Instrumental analyses show that the porous C@SnOx nanosheets exhibit a remarkably large surface area of 221 m2 g−1, delivering a reversible discharge capacity of 510 mA h g−1 after 100 cycles at 100 mA g−1, demonstrating great potential for Na+ storage applications. The superior electrochemical performance is ascribed to the unique hierarchical porous architecture which greatly facilitates electrolyte penetration and ion transportation with the carbon coating further increasing the electrode conductivity and alleviating strains generated by volume change upon Na+ ion insertion/extraction.

We report the dramatic triggering of structural order in a Zr(IV)-based metal–organic framework (MOF) through docking of HgCl2 guests. Although as-made crystals were unsuitable for single crystal X-ray diffraction (SCXRD), with diffraction limited to low angles well below atomic resolution due to intrinsic structural disorder, permeation of HgCl2 not only leaves the crystals intact but also resulted in fully resolved backbone as well as thioether side groups. The crystal structure revealed elaborate HgCl2-thioether aggregates nested within the host octahedra to form a hierarchical, multifunctional net. The chelating thioether groups also promote Hg(II) removal from water, while the trapped Hg(II) can be easily extricated by 2-mercaptoethanol to reactivate the MOF sorbent.

A simple molecule, tetrafluoroterephthalonitrile (4F-2CN), was discovered to be an efficient fluorescent probe for detecting biological thiol species. The probe responded to Cys and emitted strong green fluorescence, whereas it reacted with Hcy/GSH and generated blue fluorescence. Addition of CTAB (cetyl trimethylammonium bromide) was observed to alter the fluorescence color of the reaction product of 4F-2CN and Hcy (from blue to green), but no alteration of the fluorescence color occurred for Cys and GSH. For the very first time, cell imaging experiments showed that the three commonly occurring thiols (Cys/Hcy/GSH) could be differentiated using a single fluorescent probe. In addition, the reaction product of 4F-2CN and Cys exhibits two-photon properties, offering a potentially useful tool for tissue imaging studies. To the best of our knowledge, 4F-2CN is currently the smallest fluorescent probe for thiol detection. We envision that this new and versatile probe will be a useful tool for further elucidating the roles of thiols in biology.

•Fabrication of Sn/Cu bilayer films by a convenient cold-rolling method.•1-D nanoporous SnO2 on Cu substrates directly fabricated by anodization.•Application of the novel SnO2/Cu structure for Na-ion storage.•Remarkable capacitance and long-term stability enabled.We present a convenient, low-cost strategy to fabricate one-dimensional, vertically oriented nanoporous assembly of SnO2 upon a Cu substrate as a potentially promising anode system for Na-ion batteries application. The major novelty of the fabrication stage resides in anodizing a Sn/Cu bilayer film that is created by a facile cold-rolling procedure amenable to large-scale production. The open, nanoporous morphology of SnO2 facilitates the diffusion of electrolytes to access the SnO2 surface. The high porosity of the SnO2 phase also provides large void space to effectively accommodate the volume expansion/contraction during sodiation/desodiation. As a result, the 1-D nanoporous SnO2 thus assembled on the Cu substrate can be directly used as an effective electrode system for Na-ion storage–without the need for additives, delivering a remarkable capacity of 326 mA h g−1 over 200 cycles at a current rate of 0.2 C.Vertically oriented nanoporous SnO2 is directly grown on Cu foil by anodizing a Sn/Cu bilayer film that is fabricated using a facile cold rolling method. Without the need for any additives/binders, the specimens thus obtained are readily applicable as high-performance Na-ion battery electrodes.

A Zr(IV)-based metal–organic framework (MOF) appended with free-standing thiol (–SH) groups was found to react readily with I2 molecules to form sulfenyl iodide (S-I) units. In contrast to its solution chemistry of facile disproportionation into disulfide and I2, the sulfenyl iodide (SI) function, anchored onto the rigid MOF grid and thus prevented from approaching one another to undergo the dismutation reaction, exhibits distinct stability even at elevated temperatures (e.g., 90 °C). On a conceptual plane, this simple and effective solid host also captures the spatial confinement observed for the complex biomacromolecular scaffolds involved in iodine thyroid chemistry, wherein the spatial isolation and consequent stabilization of sulfenyl/selenenyl iodides are exerted by means of the protein scaffolds.

We report a robust metal–organic framework (MOF) for convenient recovery of Pd(II) from acidic nitric solutions which emulate high-level liquid wastes (HLLW) generated from the reprocessing of spent nuclear fuel. The framework solid (ASUiO-66) was constructed from Zr(IV) ions and the multifunctional linker 2,6-bis(allylsulfanyl)terephthalic acid (H2L), and features the well-known UiO-66 topology. Herein the robust Zr(IV)-carboxylate bonds impart structural strength to the host net, while the alkene and thioether units provide efficient and selective binding of the Pd(II) ions. For example, over 95% of the Pd(II) ions can be adsorbed from a simulated HLLW (1.0 M HNO3, containing about 20 different types of metal elements), with Ag(I) being the only other metal ion taken up significantly by the ASUiO-66 sorbent. Moreover, the adsorbed Pd(II) species can be effectively stripped by a dilute solution of thiourea (0.01 M); and the regenerated framework solid can be used for additional cycles of Pd extraction, with the sorption capacity for Pd(II) being little changed (38–41 mg g−1). The isotherm adsorption data fit well with the Langmuir model with a saturation capacity of 45.4 mg g−1, being equivalent to each octahedral cage in the UiO-66 net containing roughly one Pd(II) ion. In a broader perspective, the alkene and thioether combination could be anchored onto other sorbent systems (e.g., porous polymers and resins) to impart versatile adsorption properties for the retrieval of noble metal ions.

Self-standing thiol (−SH) groups within a Zr(IV)-based metal–organic framework (MOF) anchor Pd(II) atoms for catalytic applications: the spatial constraint prevents the thiol groups from sealing off/poisoning the Pd(II) center, while the strong Pd–S bond precludes Pd leaching, enabling multiple cycles of heterogeneous catalysis to be executed.

Correction for ‘Tackling poison and leach: catalysis by dangling thiol–palladium functions within a porous metal–organic solid’ by Bo Gui et al., Chem. Commun., 2015, DOI: 10.1039/c5cc00140d.

Thiol (–SH) groups within a Zr(IV)-based metal–organic framework (MOF) anchor Hg(II) atoms; oxidation by H2O2 then leads to acidic sulfonate functions for catalyzing acetylene hydration at room temperature.

In a metal-free procedure, chelating thiol groups and an electrophile react to assemble a robust, conjugated porous polymer with pendant aldehyde functionalities. These groups are able to reduce Ag(I) ions to generate, in situ, Ag(0) nanoparticles evenly dispersed in the polymer matrix. The Ag(0)–polymer composite enables selective reduction of aromatic nitro compounds as a heterogeneous catalyst, and can be conveniently recycled multiple times.

From a hydrothermal reaction using CuI, KI, and 3,3′5,5′-tetramethyl-4,4′-bipyrazole (TMBP), the triiodide anion I3– has been integrated into the water-stable 2D coordination polymer Cu(TMBP)I3 (1). In contrast with other metal triiodide complexes, 1 features remarkably small distortions in the bond distances associated with the I3– units (i.e., the Cu–I and I–I bonds), which effectively link up the copper(I) centers into infinite CuI3 chains. The electronic band gaps and electrical conductivity data are also found to be consistent with the I3– ion acting as an effective linker across the copper(I) centers.

Merging is the simple term that captures the spirit of this article. This refers to merging, both structurally and functionally, the distinct moieties of the backbone and the side group in the topical design of the porous solids of metal–organic frameworks (MOFs). As the backbone has been traditionally the focus of study, merging translates into the rise of the side group functions, which have of late proven to be increasingly important for the functionalization of the porous grid. The wide range of usable organic side groups, however, also presents a paradox of choice. Instead of mechanically latching the side groups onto the backbone (i.e., with their innate solution-phase reactivity more or less retained), we focus on distinct, dramatic synergism. Distinct being a subjective term open to dispute, we specify two modes of merging/integration. One involves the unconventional, backfolded shape of the ligand, in which rigid side arms coalesce with the backbones to generate multiple pre-assembled subunits (i.e., the simple tritopic subunits), each of which conforms to the traditional starburst shape. The other mode of merging involves crosslinking the side groups, which broadly ranges from the earlier use of simple σ bond links for mechanical locking in the MOF grid, to the use of more polarizable metal–chalcogenide or organic π bridges that stand to transform the insulating MOF grid into next-generation solid-state electronic materials.

Separating silver (Ag+) from lead (Pb2+) is one of the many merits of the porous polymer framework reported here. The selective metal binding stems from the well-defined chelating unit of N-heterocycles, which consists of a triazine (C3N3) ring bonded to three 3,5-dimethylpyrazole moieties. Such a rigid and open triad also serves as the distinct building unit in the fully conjugated 3D polymer scaffold. Because of its strong fluorescence and porosity (e.g., BET surface area: 355 m2/g), and because of the various types of metal species that can be readily taken up, this versatile framework is especially fit for functionalization. For example, with AgNO3 loaded, the framework solid exhibits a brown color in response to water solutions of H2S, even at the dilution of 5.0 μM (0.17 ppm); whereas cysteine and other biologically relevant thiols do not cause notable change in color. In another example, tunable white-light emission was produced when an Ir(III) complex was doped (e.g., about 0.02% of the polymer weight) onto the framework. Mechanistically, the bound Ir(III) centers become highly emissive in the orange-red region, complementing the broad, bluish emission from the polymer host to result in the overall white-light quality: the color attributes of the emission are therefore easily tunable by the Ir(III) dopant concentration. With this exemplary study, we intend to highlight metal uptake as an effective approach to modify and enrich the properties of porous polymer frameworks and to stimulate interest in further examining metal–polymer interactions in the context of sensing, separation, catalyzes, and other applications.

Simple synthesis and versatile functions: by directly reacting a triphenylene hexathiol molecule (HTT) with PtCl2, a covalent metal–organic framework (CMOF) has been prepared that features substantial porosity, redox activity and ion exchange capability.

The major discovery here is a robust and water-stable metal–organic framework (MOF) material capable of reversible binding of the volatile and reactive molecules of ICl and I2. The immobilization of I2 and ICl, as well as their controllable release thus achieved, is to facilitate the wide-ranging applications of these volatile species as catalysts and reagents in chemical and industrial processes. The framework material TMBP·CuI (hereafter TCuI) can be conveniently prepared in quantitative yields by heating CuI and the organic linker TMBP (3,3′,5,5′-tetramethyl-4,4′-bipyrazol) in acetonitrile. The microporous three-dimensional net of TCuI features CuI chains that contribute to efficient and reversible binding of ICl and I2 molecules, to result in the stoichiometrically well-defined adducts of TCuI·ICl and TCuI·I2, respectively. Moreover, the confinement of a volatile compound like ICl within the MOF medium provides unique opportunities to enhance its reactivity and selectivity as a chemical reagent, as is exemplified by the iodination reactions examined herein. With this exemplary study, we intend to stimulate interest in further exploring MOFs and other porous media (e.g., porous polymers) for entrapping ICl and other volatile reagents (e.g., Br2, SCl2, S2Cl2, and SOCl2) and for potentially novel reactivity associated with the porous medium.

Free-standing, accessible thiol (−SH) functions have been installed in robust, porous coordination networks to provide wide-ranging reactivities and properties in the solid state. The frameworks were assembled by reacting ZrCl4 or AlCl3 with 2,5-dimercapto-1,4-benzenedicarboxylic acid (H2DMBD), which features the hard carboxyl and soft thiol functions. The resultant Zr-DMBD and Al-DMBD frameworks exhibit the UiO-66 and CAU-1 topologies, respectively, with the carboxyl bonded to the hard Zr(IV) or Al(III) center and the thiol groups decorating the pores. The thiol-laced Zr-DMBD crystals lower the Hg(II) concentration in water below 0.01 ppm and effectively take up Hg from the vapor phase. The Zr-DMBD solid also features a nearly white photoluminescence that is distinctly quenched after Hg uptake. The carboxyl/thiol combination thus illustrates the wider applicability of the hard-and-soft strategy for functional frameworks.

A highly specific, distinct color change in the crystals of a metal–organic framework with pendant allyl thioether units in response to Pd species was discovered. The color change (from light yellow to orange/brick red) can be triggered by Pd species at concentrations of a few parts per million and points to the potential use of these crystals in colorimetric detection and quantification of Pd(II) ions. The swift color change is likely due to the combined effects of the multiple functions built into the porous framework: the carboxyl groups for bonding with Zn(II) ions to assemble the host network and the thioether and alkene functions for effective uptake of the Pd(II) analytes (e.g., via the alkene–Pd interaction). The resultant loading of Pd (and other noble metal) species into the porous solid also offers rich potential for catalysis applications, and the alkene side chains are amenable to wide-ranging chemical transformations (e.g., bromination and polymerization), enabling further functionalization of the porous networks.

This work builds on the recently developed hard–soft approach, as is embodied in the carboxyl–thioether combination, for functionalizing metal–organic frameworks (MOFs), and it aims to further demonstrate its efficacy and generality in connection with the prototypic MOF-5 system [i.e., Zn4O(bdc)3, where bdc is 1,4-benzene dicarboxylate]. Specifically, the thioether side chain CH3SCH2CH2S– (methylthioethylenethio, or MSES) is placed at the 2,5- positions of bdc, and the resultant molecule (L) was crystallized with Zn(II) ions into a porous, cubic network [Zn4O(L)3] topologically equivalent to MOF-5. Compared with the previously used methylthio (CH3S−) group, the MSES side chain is more flexible, has more S atoms as the binding sites (per chain), and extends further into the channel region; therefore, this side chain is predisposed for more-efficient binding to soft metal species when installed in a porous MOF matrix. Here, we report the significantly improved properties, with regard to stability to moisture, fluorescence intensity, and capability of metal uptake. For example, activated solid samples of 1 feature long-term stability (more than 3 weeks) in air, have a notable sensing response to nitrobenzene (in the form of fluorescence quenching), and are capable of taking up HgCl2 from an ethanol solution at a concentration as low as 84 mg/L.Keywords: fluorescent sensor; heavy metal removal; metal−organic frameworks; sulfurated frameworks; thioether donors;

We report dynamic, multiple single-crystal to single-crystal transformations of a coordination network system based on a semirigid molecule, TCPSB = 1,3,5-tri(4′-carboxyphenylsulphonyl)benzene, which nicely balances shape persistence and flexibility to bring about the framework dynamics in the solid state. The networks here generally consist of (1) the persistent core component (denoted as CoTCPSB) of linear CoII aqua clusters (Co–O–Co–O-Co) integrated into 2D grids by 4,4′-bipyridine and TCPSB and (2) ancillary ligands (AL) on the two terminal CoII ions—these include DMF (N,N′-dimethylformamide), DMA (N,N′-dimethylacetamide), CH3CN, and water. Most notably, the ancillary ligand sites are highly variable and undergo multiple substitution sequences while maintaining the solid reactants/products as single-crystals amenable to X-ray structure determinations. For example, when immersed in CH3CN, the AL of an as-made single crystal of CoTCPSB–DMF (i.e., DMF being the AL) is replaced to form CoTCPSB–CH3CN, which, in air, readily loses CH3CN to form CoTCPSB–H2O; the CoTCPSB–H2O single crystals, when placed in DMF, give back CoTCPSB–DMF in single-crystal form. Other selective, dynamic exchanges include the following: CoTCPSB–DMF reacts with CH3CN (to form CoTCPSB–CH3CN) but NOT with water, methanol, ethanol, DMA, or pyridine; CoTCPSB–H2O specifically pick outs DMF from a mixture of DMF, DMA, and DEF; an amorphous, dehydrated solid from CoTCPSB–H2O regains crystalline order simply by immersion in DMF (to form CoTCPSB–DMF). Further exploration with functional, semirigid ligands like TCPSB shall continue to uncover a wider array of advanced dynamic behaviors in solid state materials.

This paper aims to illustrate the rich potential of the thioether-carboxyl combination in generating coordination networks with tunable and interesting structural features. By simply varying the ratio between Cu(NO3)2 and the bifunctional ligand tetrakis(methylthio)benzenedicarboxylic acid (TMBD) as the reactants, three coordination networks can be hydrothermally synthesized in substantial yields, which present a distinct evolution with regard to metal−ligand interactions. Specifically, Cu(TMBD)0.5(H2TMBD)0.5·H2TMBD (1) was obtained with a relatively small (1:1) Cu(NO3)2/TMBD ratio, and crystallizes as an one-dimensional (1D) coordination assembly based on Cu(I)-thioether interactions, which is integrated by hydrogen-bonding to additional H2TMBD molecules to form a three-dimensional (3D) composite network with all the carboxylic acid and carboxylate groups remaining uncoordinated to the metal ions. A medium (1.25:1) Cu(NO3)2/TMBD ratio leads to compound Cu2TMBD, in which Cu(I) ions simultaneously bond to the carboxylate and thioether groups, while an even higher (2.4:1) Cu(NO3)2/TMBD ratio produced a mixed-cation compound CuII2OHCuI(TMBD)2·2H2O (2), in which the carboxylic groups are bonded to (cupric) CuII ions, and the thioether groups to CuI. Despite the lack of open channels in 2, crystallites of this compound exhibit a distinct and selective absorption of NH3, with a concomitant color change from green to blue, indicating substantial network flexibility and dynamics with regards to gas transport.

A silver(I) sulfide species is now imbedded in a porous coordination network. Such a composite system builds on the molecule tetrakis(methylthio)-1,4-benzenedicarboxate that holds out the hard carboxylate to europium(III) to form a host net, while taking on AgCl using its soft sulfur side arms. AgCl is then treated with H2S to form the dark-colored Ag2S species, while leaving the hard host net intact and upstanding. This hard−soft duality serves to conjoin the rich electronic flavors of metal chalcogenides and the flexible textures of coordination nets.

The large tetrapod tetrakis[(4-methylthiophenyl)ethynyl]silane was crystallized with AgBF4 to form a diamondoid network based on the Ag(I)−thioether interaction. A 4-fold interpenetration of the individual nets was observed, with the rest of the unit-cell volume occupied by the benzene guests. The benzene molecules can be removed without collapsing of the host networks, even though the benzene molecules appear to be well enclathrated in the cavities formed by the host nets. Interestingly, the apohost displays a strict size selectivity for small aromatic molecules, which effectively excludes ortho- and meta-substituted benzene derivatives from entering the pores, enabling, for example, the selective sorption of benzene over hexafluorobenzene. The fluorescence arising from the molecular building block also provides for the sensing of nitrobenzene molecules, which effectively quenches the fluorescence upon entry into the host net.

Bifunctional tetrakis(methylthio)-1,4-benzenedicarboxylic acid and Pb2+ ions form a robust porous net featuring free-standing thioether groups that allow reversible uptake of HgCl2.

We use the unifying concept of self-similarity to design and construct solid-state networks. The coordination networks reported here feature distinct correlation between the self-similar features of discrete molecules and the hierarchical patterns in infinite networks. We use as the building block a symmetrically backfolded, supertritopic dendrimer, which coordinates with AgSbF6 to form complex layered networks that can be dissected as hexagonal hierarchy patterns inherently derived from the self-similar features of the individual molecules.

This paper aims to explore the regular structural patterns and the associated electronic properties of a group of hybrid networks based on BiBr3 and aromatic thioethers, with emphasis on structurally correlating the organic molecules with the BiBr3 aggregates as well as the overall hybrid networks. It was found that extended BiBr3 chains tend to be associated with the slender 4-methylthiophenylalkynyl units, whereas biaryl-based molecules with 4-MeSPh groups directly linked to aromatic cores form hybrids with discrete BiBr3 clusters of variable nuclearities and connectivities. By using multidentate ligands with open geometries, this exploratory study also achieves hybrid BiBr3-aromatic thioether networks with open framework and higher dimensional (e.g., 3D) features, which are potentially amenable to further study on guest exchange experiments. Diffuse reflectance measurements on the powder samples of the hybrids and the organic molecules reveal significant electronic interactions between the inorganic and organic components, with the absorption edges of the hybrids uniformly shifted to lower energies relative to the organic samples. In systems with similar network connectivity and local bonding features, the shifts appear to be proportional to the absorption energy of the organic molecules, suggesting that, in a first order approximation, the absorption edge in the hybrids involves substantially the electronic transitions from the HOMOs of the organic molecules to the LUMOs (or conduction bands) of the inorganic components.

From searching the Cambridge Structural Database (CSD), we noticed an exceptionally widespread distribution of the interatomic distances (from 2.39 to 3.52 Å) between thioether S atoms and Ag(I) ions, in comparison with the cases in other common ligands such as nitriles and pyridyls. The variable bonding distances point to a highly flexible and reversible nature of thioether−Ag(I) interaction, which might help crystallize large and complex organic molecules into ordered coordination networks under mild conditions. We provide a number of new structures for illustration. In 1, two Ag(I) ions are coordinated by three 1,2,3-tris(methylthio)phenyl groups (i.e., 9 S atoms) to form a three-bladed paddlewheel block as a node for an enlarged honeycomb sheet. In 2, a porphyrin molecule with four 1,2,3-tris(phenylthio)phenyl groups coordinates to Ag(I) atoms to form a parallelogram net, featuring free-standing phenylthio groups in the channel. In 3, a starburst molecule with six 4-methylthiophenyl groups attached to the triphenylene core is crystallized with AgOTf (triflate) to form a complex three-dimensional net, with a supramolecular topology featuring a combination of edge-sharing octahedra (the rutile chain) and vertex-sharing octahedra (the ReO3 chain).

The simple and easy-to-prepare bifunctional molecule 2,5-dimercapto-1,4-benzenedicarboxylic acid (H4DMBD) interacts with the increasingly harder metal ions of Cu+, Pb2+ and Eu3+ to form the coordination networks of Cu6(DMBD)3(en)4(Hen)6 (1), Pb2(DMBD)(en)2 (2) and Eu2(H2DMBD)3(DEF)4 (3), where the carboxyl and thiol groups bind with distinct preference to the hard and soft metal ions, respectively. Notably, 1 features uncoordinated carboxylate groups and Cu3 cluster units integrated via the thiolate groups into an extended network with significant interaction between the metal centers and the organic molecules; 2 features a 2D coordination net based on the mercapto and carboxylic groups all bonded to the Pb2+ ions; 3 features free-standing thiol groups inside the channels of a metal-carboxylate-based network. This study illustrates the rich solid state structural features and potential functions offered by the carboxyl-thiol combination.Molecule 2,5-dimercapto-1,4-benzenedicarboxylic acid was reacted with Cu+, Pb2+ and Eu3+ ions to explore solid state networks with the rich structural features arising from the carboxyl-thiol combination.

Four cubane-like Cu4I4 units are assembled around an iodine atom to form the giant, mixed-valent CuIICuI15I17 cluster. The CuIICuI15I17 cluster and a bipyrazole linker form a 3D open framework with paramagnetic and thermochromic properties. This paper also touches on the resemblance of this cluster to the self-similar object of a Sierpinski tetrahedron.

The bifunctional molecule tetrakis(methylthio)-1,4-benzenedicarboxylic acid (TMBD) interacts with the increasingly harder metal ions of CuI, CdII, and ZnII to form the coordination networks of Cu2TMBD, CdTMBD, and Zn4O(H2O)3(TMBD)3, where the carboxyl group consistently bonds to metal ions, while the softer methylthio group binds with preference to the softer metal ions (i.e., chelation to Cu+, single-fold coordination to Cd2+, and nonbonding to Zn2+). Diffuse-reflectance spectra show that the metal−thioether interaction is associated with smaller electronic band gaps of the solid-state networks.

The large aromatic ligand 9,10-bis{[3,4-bis(methylthio)phenyl]ethynyl}anthracene (L) interacts with CuCN to form a 2D, fluorescent hybrid network, L·2CuCN. Although the edge-to-face stacking between the organic π-electron systems prevails in the molecular crystal structure of L, the face-to-face stacking becomes more distinct in L·2CuCN. A preliminary survey on similar hybrid networks in the Cambridge Structural Database (CSD) suggests that 1D inorganic moieties may help maintain and induce cofacial stacking of the associated aromatic ligands.

Centripetally shaped molecules are crystallized with AgSbF6 to yield coordination networks featuring novel coordination modes, network connectivity and chiral/helical structures.

This paper reports on the strong tendency of a group of thioether and selenoether molecules to adopt non-centrosymmetric and non-interpenetrating features in forming 3D coordination networks with metal ions. We illustrate such tendency with the (10, 3)-a nets formed by Ag(I) ions and the large aromatic ligands of 1,3,6,8-tetrakis(phenylseleno)pyrene (TPhSeP) and 2,3,6,7,10,11-hexakis(phenylseleno)triphenylene (HPhSeT). In particular, TPhSeP interacts with AgSbF6 to provide a 3D chiral network based on trimeric coordination building blocks. Each trimeric building block is rather complex and consists of three pairs of TPhSeP molecules integrated through the Ag+ ions into a circular unit. The circular, trimeric units function as the three-connected nodes, which are further connected through the Ag+ ions to generate the (10, 3)-a topology. By comparison, the connectivity of the HPhSeT-based net is simpler, with the trigonal-shaped HPhSeT molecules acting as three-connected nodes that are integrated into a (10, 3)-a topology by means of the bridging Ag(I) ions. Other related networks are also briefly discussed to further illustrate the potential generality of the occurrence of non-centrosymmetric and non-interpenetrating features in networks formed by these molecules.

This paper reports our recent efforts in using host–guest interactions to control the fluorescent properties of coordination networks containing polycyclic aromatic units. The polycyclic aromatic ligand 2,3,6,7,10,11-hexakis(phenylthio)triphenylene (HPhTT) coordinates with AgTf (Tf: trifluoromethanesulfonate) in nitrobenzene to form single crystals of a 2-D host network consisting of octameric (i.e., containing eight AgTf units) and dimeric AgTf moieties linked to the HPhTT molecules through the Ag-thioether coordination bonds. The HPhTT adopts a starburst and rather irregular conformation, which apparently contributes to the formation of empty space between the 2-D coordination networks. Such voids are occupied by the nitrobenzene guest molecules, resulting in distinct aromatic–aromatic stacking interactions with the triphenylene units (interplanar distances: 3.46 and 3.60 Å). In comparison to a previous Ag-HPhTT network with toluene as weaker-interacting guests, the current system shows a significantly suppressed fluorescent emission from the triphenylene core, apparently due to the quenching effect from the nitrobenzene guests.Well-defined host–guest interactions are observed and apparently lead to subdued fluorescence in a coordination network of 2,3,6,7,10,11-hexakis(phenylthio)triphenylene and silver(I) triflate.

Carbon-coated binder-free flexible porous SnOx nanosheets (SnO/SnO2 heterogeneous structure) were fabricated and tested as anode materials for Na-ion batteries (NIBs). The novel free-standing and binder-free porous C@SnOx nanosheets were first self-assembled on a Cu substrate via a facile, low-cost anodization method followed by the carbonization treatment. Instrumental analyses show that the porous C@SnOx nanosheets exhibit a remarkably large surface area of 221 m2 g−1, delivering a reversible discharge capacity of 510 mA h g−1 after 100 cycles at 100 mA g−1, demonstrating great potential for Na+ storage applications. The superior electrochemical performance is ascribed to the unique hierarchical porous architecture which greatly facilitates electrolyte penetration and ion transportation with the carbon coating further increasing the electrode conductivity and alleviating strains generated by volume change upon Na+ ion insertion/extraction.

Thiol (–SH) groups within a Zr(IV)-based metal–organic framework (MOF) anchor Hg(II) atoms; oxidation by H2O2 then leads to acidic sulfonate functions for catalyzing acetylene hydration at room temperature.

Self-standing thiol (−SH) groups within a Zr(IV)-based metal–organic framework (MOF) anchor Pd(II) atoms for catalytic applications: the spatial constraint prevents the thiol groups from sealing off/poisoning the Pd(II) center, while the strong Pd–S bond precludes Pd leaching, enabling multiple cycles of heterogeneous catalysis to be executed.

Correction for ‘Tackling poison and leach: catalysis by dangling thiol–palladium functions within a porous metal–organic solid’ by Bo Gui et al., Chem. Commun., 2015, DOI: 10.1039/c5cc00140d.

In a metal-free procedure, chelating thiol groups and an electrophile react to assemble a robust, conjugated porous polymer with pendant aldehyde functionalities. These groups are able to reduce Ag(I) ions to generate, in situ, Ag(0) nanoparticles evenly dispersed in the polymer matrix. The Ag(0)–polymer composite enables selective reduction of aromatic nitro compounds as a heterogeneous catalyst, and can be conveniently recycled multiple times.

Simple synthesis and versatile functions: by directly reacting a triphenylene hexathiol molecule (HTT) with PtCl2, a covalent metal–organic framework (CMOF) has been prepared that features substantial porosity, redox activity and ion exchange capability.

Centripetally shaped molecules are crystallized with AgSbF6 to yield coordination networks featuring novel coordination modes, network connectivity and chiral/helical structures.

A simple molecule, tetrafluoroterephthalonitrile (4F-2CN), was discovered to be an efficient fluorescent probe for detecting biological thiol species. The probe responded to Cys and emitted strong green fluorescence, whereas it reacted with Hcy/GSH and generated blue fluorescence. Addition of CTAB (cetyl trimethylammonium bromide) was observed to alter the fluorescence color of the reaction product of 4F-2CN and Hcy (from blue to green), but no alteration of the fluorescence color occurred for Cys and GSH. For the very first time, cell imaging experiments showed that the three commonly occurring thiols (Cys/Hcy/GSH) could be differentiated using a single fluorescent probe. In addition, the reaction product of 4F-2CN and Cys exhibits two-photon properties, offering a potentially useful tool for tissue imaging studies. To the best of our knowledge, 4F-2CN is currently the smallest fluorescent probe for thiol detection. We envision that this new and versatile probe will be a useful tool for further elucidating the roles of thiols in biology.

A Zr(IV)-based metal–organic framework (MOF) appended with free-standing thiol (–SH) groups was found to react readily with I2 molecules to form sulfenyl iodide (S-I) units. In contrast to its solution chemistry of facile disproportionation into disulfide and I2, the sulfenyl iodide (SI) function, anchored onto the rigid MOF grid and thus prevented from approaching one another to undergo the dismutation reaction, exhibits distinct stability even at elevated temperatures (e.g., 90 °C). On a conceptual plane, this simple and effective solid host also captures the spatial confinement observed for the complex biomacromolecular scaffolds involved in iodine thyroid chemistry, wherein the spatial isolation and consequent stabilization of sulfenyl/selenenyl iodides are exerted by means of the protein scaffolds.

This paper aims to explore the regular structural patterns and the associated electronic properties of a group of hybrid networks based on BiBr3 and aromatic thioethers, with emphasis on structurally correlating the organic molecules with the BiBr3 aggregates as well as the overall hybrid networks. It was found that extended BiBr3 chains tend to be associated with the slender 4-methylthiophenylalkynyl units, whereas biaryl-based molecules with 4-MeSPh groups directly linked to aromatic cores form hybrids with discrete BiBr3 clusters of variable nuclearities and connectivities. By using multidentate ligands with open geometries, this exploratory study also achieves hybrid BiBr3-aromatic thioether networks with open framework and higher dimensional (e.g., 3D) features, which are potentially amenable to further study on guest exchange experiments. Diffuse reflectance measurements on the powder samples of the hybrids and the organic molecules reveal significant electronic interactions between the inorganic and organic components, with the absorption edges of the hybrids uniformly shifted to lower energies relative to the organic samples. In systems with similar network connectivity and local bonding features, the shifts appear to be proportional to the absorption energy of the organic molecules, suggesting that, in a first order approximation, the absorption edge in the hybrids involves substantially the electronic transitions from the HOMOs of the organic molecules to the LUMOs (or conduction bands) of the inorganic components.

We report a robust metal–organic framework (MOF) for convenient recovery of Pd(II) from acidic nitric solutions which emulate high-level liquid wastes (HLLW) generated from the reprocessing of spent nuclear fuel. The framework solid (ASUiO-66) was constructed from Zr(IV) ions and the multifunctional linker 2,6-bis(allylsulfanyl)terephthalic acid (H2L), and features the well-known UiO-66 topology. Herein the robust Zr(IV)-carboxylate bonds impart structural strength to the host net, while the alkene and thioether units provide efficient and selective binding of the Pd(II) ions. For example, over 95% of the Pd(II) ions can be adsorbed from a simulated HLLW (1.0 M HNO3, containing about 20 different types of metal elements), with Ag(I) being the only other metal ion taken up significantly by the ASUiO-66 sorbent. Moreover, the adsorbed Pd(II) species can be effectively stripped by a dilute solution of thiourea (0.01 M); and the regenerated framework solid can be used for additional cycles of Pd extraction, with the sorption capacity for Pd(II) being little changed (38–41 mg g−1). The isotherm adsorption data fit well with the Langmuir model with a saturation capacity of 45.4 mg g−1, being equivalent to each octahedral cage in the UiO-66 net containing roughly one Pd(II) ion. In a broader perspective, the alkene and thioether combination could be anchored onto other sorbent systems (e.g., porous polymers and resins) to impart versatile adsorption properties for the retrieval of noble metal ions.