Christoph Janiak

MOFs, MILs and more: concepts, properties and applications for porous coordination networks (PCNs)

This review (over 380 references) summarizes metal–organic frameworks (MOFs), Materials Institute Lavoisier (MILs), iso-reticular metal–organic frameworks (IR-MOFs), porous coordination networks (PCNs), zeolitic metal–organic frameworks (ZMOFs) and porous coordination polymers (PCPs) with selected examples of their structures, concepts for linkers, syntheses, post-synthesis modifications, metal nanoparticle formations in MOFs, porosity and zeolitic behavior for applications in gas storage for hydrogen, carbon dioxide, methane and applications in conductivity, luminescence and catalysis.

Engineering coordination polymers towards applications

The development in the field of coordination polymers or metal-organic coordination networks, MOCNs (metal-organic frameworks, MOFs) is assessed in terms of property investigations in the areas of catalysis, chirality, conductivity, luminescence, magnetism, spin-transition (spin-crossover), non-linear optics (NLO) and porosity or zeolitic behavior upon which potential applications could be based.

Recent advances in crystal engineering

The articles published in the tenth anniversary issue of CrystEngComm are reviewed. The issue highlighted the state-of-the-art of crystal engineering and new trends and developing areas in crystal engineering. In particular, the following article emphasises developments in the areas of intermolecular interactions, notably hydrogen and halogen bonds; metal–organic frameworks or coordination polymers; polymorphism and solvates.

A critical account on π–π stacking in metal complexes with aromatic nitrogen-containing ligands

A geometrical analysis has been performed on π–π stacking in metal complexes with aromatic nitrogen-containing ligands based on a Cambridge Structural Database search and on X-ray data of examples in the recent literature. It is evident that a face-to-face π–π alignment where most of the ring-plane area overlaps is a rare phenomenon. The usual π interaction is an offset or slipped stacking, i.e. the rings are parallel displaced. The ring normal and the vector between the ring centroids form an angle of about 20° up to centroid–centroid distances of 3.8 A. Such a parallel-displaced structure also has a contribution from π–σ attraction, the more so with increasing offset. Only a limited number of structures with a near to perfect facial alignment exists. The term π–π stacking is occasionally used even when there is no substantial overlap of the π-ring planes. There is a number of metal–ligand complexes where only the edges of the rings interact in what would be better described a C–H⋯π attraction.

MOFs as Adsorbents for Low Temperature Heating and Cooling Applications

The 3D metal-organic framework (MOF) (3)(infinity){[Ni(3)(mu(3)-btc)(2)(mu(4)-btre)(2)(mu-H(2)O)(2)]. approximately 22H(2)O} is found to be a reversibly dehydratable-hydratable water-stable MOF material with a large loading spread of 210 g/kg as a candidate for solid adsorbents in heat transformation cycles for refrigeration, heat pumping, and heat storage.

Metal catalysts for the vinyl polymerization of norbornene

A full literature and patent account (about 100 references) is given on work describing the vinyl polymerization to homo-polynorbornene. The interest in vinyl homo-polynorbornene is driven by its dielectric and mechanical properties for the technical application as an interlevel dielectric in microelectronics applications. The norbornene/olefin copolymerization is covered to some extent for comparison. The metal catalysts are presented and important polymer product properties are emphasized.

Crystal structures and solid-state CPMAS 13C NMR correlations in luminescent zinc(II) and cadmium(II) mixed-ligand coordination polymers constructed from 1,2-bis(1,2,4-triazol-4-yl)ethane and benzenedicarboxylate

The hydrothermal reaction of M(NO(3))(2).4H(2)O (M = Zn and Cd) with benzene-1,4-dicarboxylic acid (H(2)bdc) or benzene-1,3-dicarboxylic acid (H(2)ip) and 1,2-bis(1,2,4-triazol-4-yl)ethane (btre) produced the mixed-ligand coordination polymers (MOFs) {[Zn(2)(micro(2)-bdc)(2)(micro(4)-btre)]} (), {[Cd(2)(micro(4)-bdc)(micro(4)-btre)(2)](NO(3))(2).H(2)O} and {[Zn(2)(micro(3)-ip)(2)(micro(2)-btre)(H(2)O)(2)].2H(2)O} (). The compounds, characterized by single-crystal X-ray diffraction, X-ray powder diffraction, solid-state cross-polarization (CP) magic-angle-spinning (MAS) (13)C NMR and thermoanalysis, feature 3D metal-organic frameworks for and and 2D double layers which are connected through hydrogen bonds from the aqua ligands for 3. The CPMAS (13)C NMR spectra picture the symmetry-independent (unique) C atoms and the bdc/ip-to-btre ligand ratio in agreement with the crystal structures. The zinc and cadmium coordination polymers show a strong bluish fluorescence upon excitation with UV light (the free btre ligand is non-luminescent).

The Vinyl Homopolymerization of Norbornene

A full literature and patent account (about 100 references) is given on work describing vinyl polymerization of form the homopolymer poly(norbornene). The interest in vinyl-poly(norbornene) is driven by its dielectric and mechanical properties for thte technical application as an interlevel dielectric in microelectronics applications. For comparison, the norbornene/olefin copolymerization is discussed also. The metal catalysts are introduced and important polymer product properties are emphasized. The six possible isomers for stereoregular poly(norbornene) are presented.

MIL-100(Al, Fe) as water adsorbents for heat transformation purposes—a promising application

The adsorption/desorption of up to 0.75 g of water vapour per g of the porous MOFs 3D-{M3O(X)(H2O)2[btc]2·nH2O}, MIL-100 (M = Al, Fe; X = OH, F, btc = benzene-1,3,5-tricarboxylate, trimesate), occurs at small relative pressures of p/p0 < 0.4 and a comparatively small hysteresis. Together with very good cycle stability, these properties render both MIL-100(Al and Fe) very suitable candidates for thermally driven heat pumps or adsorption chillers.

Microwave Irradiation for the Facile Synthesis of Transition-Metal Nanoparticles (NPs) in Ionic Liquids (ILs) from Metal–Carbonyl Precursors and Ru-, Rh-, and Ir-NP/IL Dispersions as Biphasic Liquid–Liquid Hydrogenation Nanocatalysts for Cyclohexene

Stable chromium, molybdenum, tungsten, manganese, rhenium, ruthenium, osmium, cobalt, rhodium, and iridium metal nanoparticles (M-NPs) have been reproducibly obtained by facile, rapid (3 min), and energy-saving 10 W microwave irradiation (MWI) under an argon atmosphere from their metal-carbonyl precursors [M(x)(CO)(y)] in the ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF(4)]). This MWI synthesis is compared to UV-photolytic (1000 W, 15 min) or conventional thermal decomposition (180-250 degrees C, 6-12 h) of [M(x)(CO)(y)] in ILs. The MWI-obtained nanoparticles have a very small (<5 nm) and uniform size and are prepared without any additional stabilizers or capping molecules as long-term stable M-NP/IL dispersions (characterization by transmission electron microscopy (TEM), transmission electron diffraction (TED), and dynamic light scattering (DLS)). The ruthenium, rhodium, or iridium nanoparticle/IL dispersions are highly active and easily recyclable catalysts for the biphasic liquid-liquid hydrogenation of cyclohexene to cyclohexane with activities of up to 522 (mol product) (mol Ru)(-1) h(-1) and 884 (mol product) (mol Rh)(-1) h(-1) and give almost quantitative conversion within 2 h at 10 bar H(2) and 90 degrees C. Catalyst poisoning experiments with CS(2) (0.05 equiv per Ru) suggest a heterogeneous surface catalysis of Ru-NPs.