A mesostructured Y zeolite as a superior FCC catalyst--lab to refinery.

A mesostructured Y zeolite was prepared by a surfactant-templated process at the commercial scale and tested in a refinery, showing superior hydrothermal stability and catalytic cracking selectivity, which demonstrates, for the first time, the promising future of mesoporous zeolites in large scale industrial applications.

Interaction of molecular hydrogen with microporous metal organic framework materials at room temperature.

Infrared (IR) absorption spectroscopy measurements, performed at 300 K and high pressures (27-55 bar) on several prototypes of metal organic framework (MOF) materials, reveal that the MOF ligands are weakly perturbed upon incorporation of guest molecules and that the molecular hydrogen (H(2)) stretch mode is red-shifted (30-40 cm(-1)) from its unperturbed value (4155 cm(-1) for ortho H(2)). For MOFs of the form M(bdc)(ted)(0.5) (bdc = 1,4-benzenedicarboxylate; ted = triethylenediamine), H(2) molecules interact with the organic ligands instead of the saturated metal centers located at the corners of the unit cell. First-principles van der Waals density functional calculations identify the binding sites and further show that the induced dipole associated with the trapped H(2) depends sensitively on these sites. For M(bdc)(ted)(0.5) systems, the strongest dipole moment is of the site that is in the corner of the unit cell and is dominated by the interaction with the benzene ligand and not by the metal center. For MOFs of the M(3)[HCOO](6) type with relatively short ligands (i.e., formate) and 1-D pore structures, there is a weak dependence of H(2) vibrational frequency on the cations, due to a small change in the unit cell dimension. Furthermore, translational states of approximately +/-100 cm(-1) are clearly observed as side bands on the H(2) stretch mode in these 1-D channels interconnected by very small apertures. The H(2) stretch IR integrated areas in all the MOFs considered in this work increase linearly with H(2) pressure, consistent with isotherm measurements performed in similar conditions. However, the IR intensity varies substantially, depending on the number of benzene rings interacting with the H(2) molecules. Finally, there is no correlation between H(2) binding energies (determined by isotherm measurements) and the magnitude of the H(2) stretch shift, indicating that IR shifts are dominated by the environment (organic ligand, metal center, and structure) rather than the strength of the interaction. These results highlight the relevance of IR spectroscopy to determine the type and arrangement of ligands in the structure of MOFs.

Zeolitic imidazolate frameworks for kinetic separation of propane and propene.

Propane/propene separation by cryogenic distillation is one of the most energy and cost intensive industrial processes. Adsorptive separation is a more energy-efficient alternative. Three isostructural zinc imidazolate zeolitic framework materials are found, for the first time, to be very promising in the separation of propene and propane based on their different diffusion rates. Fine-tuning of the pore opening size is critical for this type of separation.

RPM3: a multifunctional microporous MOF with recyclable framework and high H2 binding energy.

A microporous metal organic framework structure, Zn(2)(bpdc)(2)(bpee).2DMF (DMF: N,N-dimethylformamide), has been synthesized via solvothermal reactions. The compound is a new member of the RPM series (RPM = Rutgers Recyclable Porous Material) that possesses a flexible and recyclable three-dimensional framework containing one-dimensional channels. It exhibits interesting and multifold functionality, including porosity, commensurate adsorption for hydrocarbons, high hydrogen binding energy (determined by isosteric heats of hydrogen adsorption and confirmed by van der Waals density functional calculations) as a result of multifold binding to aromatic ligands (determined by IR spectroscopy), strong photoluminescence emission, and reversible fluorescence quenching properties.

A luminescent microporous metal-organic framework for the fast and reversible detection of high explosives.

Sensors and sensitivity: A highly luminescent microporous metal-organic framework, [Zn(2)(bpdc)(2)(bpee)] (bpdc = 4,4'-biphenyldicarboxylate; bpee = 1,2-bipyridylethene), is capable of very fast and reversible detection of the vapors of the nitroaromatic explosive 2,4-dinitrotoluene and the plastic explosive taggant 2,3-dimethyl-2,3-dinitrobutane, through redox fluorescence quenching with unprecedented sensitivity (see spectra).

Unique gas and hydrocarbon adsorption in a highly porous metal-organic framework made of extended aliphatic ligands.

High and unique gas and hydrocarbon adsorption in a highly stable guest-free microporous metal-organic framework constructed on rigid aliphatic ligands, H(2)bodc and ted, is reported in this work.

Cocrystallization of adamantane-1,3-dicarboxylic acid and 4,4'-bipyridine.

The cocrystallization of adamantane-1,3-dicarboxylic acid (adc) and 4,4'-bipyridine (4,4'-bpy) yields a unique 1:1 cocrystal, C(12)H(16)O(4).C(10)H(8)N(2), in the C2/c space group, with half of each molecule in the asymmetric unit. The mid-point of the central C-C bond of the 4,4'-bpy molecule rests on a center of inversion, while the adc molecule straddles a twofold rotation axis that passes through two of the adamantyl C atoms. The constituents of this cocrystal are joined by hydrogen bonds, the stronger of which are O-H...N hydrogen bonds [O...N = 2.6801 (17) A] and the weaker of which are C-H...O hydrogen bonds [C...O = 3.367 (2) A]. Alternate adc and 4,4'-bpy molecules engage in these hydrogen bonds to form zigzag chains. In turn, these chains are linked through pi-pi interactions along the c axis to generate two-dimensional layers. These layers are neatly packed into a stable crystalline three-dimensional form via weak C-H...O hydrogen bonds [C...O = 3.2744 (19) A] and van der Waals attractions.

Multiple bismuth(III)-thioether secondary interactions integrate metalloporphyrin ligands into functional networks.

We introduce the 1,2,3-tris(organylthiophenyl) group as a symmetrical, multidentate chelation link for building coordination networks. For this, zinc(II) 5,10,15,20-tetrakis[3',4',5'-tris(methylthio)phenyl]porphyrin was synthesized and integrated into a two-dimensional network via coordination with BiBr3. The coordination link exhibits an unusually complex bonding pattern, involving six S atoms from two neighboring ligands that form multiple Bi-S interactions (distances ranging from 3.08 to 3.63 A) with a dimerlike unit of Bi2Br6. The electronic interaction between the porphyrin center and the Bi2Br6 block was illustrated by the diffuse-reflectance spectrum of the network compound, in which a modest red-shifted feature at 1.8 eV was seen (while the Q-band absorption of the metalloporphyrin core continues to be dominant at 1.9 eV).

Three-dimensional nets from star-shaped hexakis(arylthio)triphenylene molecules and silver(I) salts.

This article reports a number of functional 3D networks based on the coordination bonds between the silver(I) ion and polycyclic aromatic 2,3,6,7,10,11-hexakis(organylthio)triphenylene (HRTT) molecules. First, 2,3,6,7,10,11-hexakis(phenylthio)triphenylene (HPhTT) chelates with AgBF4 (or AgTf, where Tf is triflate) in the presence of hexafluorobenzene to form a 3D network (composition, HPhTT x AgBF4; space group, I4), where each Ag(I) atom is bonded to three HPhTT molecules and acts as a three-connected node that interconnects the trigonal HPhTT ligands. In addition to the relatively rare 8(2) x 10-a topology, the network features distinct channel-like domains that incorporate various solvent molecules (e.g., acetone and tetrahydrofuran). The solvent molecules can be evacuated to produce a stable and crystalline apohost network, in which the solvent-accessible fraction of the cell volume is calculated to be about 16%. Second, chelation of 2,3,6,7,10,11-hexakis(4-methoxyphenylthio)triphenylene (HMOPhTT) and AgSbF6 in a 1:1 ratio results in a 3D network featuring a similar 8(2) x 10-a topology and Ag(I) coordination environment. However, the crystallographic symmetry (space group Cc) is lowered, and the feature of porosity is much less distinct. The 3D networks show strong room-temperature fluorescence bands with lambda(F,max) = 450 nm, due to the pi-electron fragment of the triphenylene group.

Semiconductive coordination networks from bismuth(III) bromide and 1,2-bis(methylthio)phenylacetylene-based ligands.

This paper reports our initial efforts to integrate phenylacetylene-based conjugate pi-electron systems into hybrid semiconductive coordination networks, as part of the larger scheme to fully synergize organic functionalities and electronic properties in crystalline solid-state materials. On the basis of a well-established Pd-catalyzed procedure, ligands of 3,3',4,4'-tetrakis(methylthio)tolan (L1) and 1,3,5-tris[[3,4-bis(methylthio)phenyl]ethynyl]benzene (L2) were efficiently synthesized in relatively simple procedures. Molecule L1 reacts with BiBr3 to form a 2D semiconductive coordination network (L1.2BiBr3), which consists of infinite chains of the BiBr3 component cross-linked by L1 through the chelation between the 1,2-bis(methylthio) groups and the Bi(III) centers. Molecule L2 reacts with BiBr3 to from a 1D semiconductive coordination network (L2.2BiBr3), which features discrete tetrameric Bi4Br12 units linked by the thioether groups from L2 [only two of the three 1,2-bis(methylthio) groups from each L2 molecule are bonded to the Bi(III) centers]. Diffuse reflectance spectra of both L1.2BiBr3 and L2.2BiBr3 feature strong optical absorptions at energy levels significantly lower than those of the corresponding molecular solids (L1 and L2) and BiBr3, indicating significant electronic interaction between the organic pi-electron systems and the BiBr3 components. Both L1.2BiBr3 and L2.2BiBr3 readily form in high yields and are stable to air, providing advantages for further studies as potentially applicable semiconductive materials.

Fluorescent coordination networks of 2,3,6,7,10,11-hexakis(phenylthio)triphenylene and silver(I) triflate.

The polycyclic aromatic ligand 2,3,6,7,10,11-hexakis(phenylthio)triphenylene (HPhTT) coordinates with AgTf (Tf = trifluoromethylsulfonate) to form 1D networks with various solvent molecules included. In particular, the crystal structures and photoluminescent properties of compound 1 (formula = 2HPhTT.3AgTf.3toluene) and compound 2 (formula = 2HPhTT.3AgTf.2THF) are described. Both 1 and 2 feature similar network connectivity as well as similar local coordination environments around the silver(I) atoms. The organizations of the guest molecules in the two structures are, however, quite different: In 1, the toluene molecules are enclathrated in isolated cavities by the host network; in 2, the THF molecules are confined in continuous 1D channels. Because of the large aromatic system of the triphenylene moiety, strong fluorescent bands (room temperature) are observed for HPhTT, 1 and 2, with lambda(F,max) = 447 nm for HPhTT and lambda(F,max) = 440 nm for both 1 and 2.