The polyhedral complex [Cu(4)L(H(2)O)(4)]solv (NOTT-140) shows a 4,8-connected structure of rare scu topology comprising octahedral and cuboctahedral cages; desolvated NOTT-140a shows a total CO(2) uptake of 314.6 cm(3)(STP) cm(-3) at 20 bar, 293 K, and a total H(2) uptake of 6.0 wt% at 20 bar, 77 K.

A (3,24)-connected mesoporous metal-organic framework, PCN-69, was synthesized by linking a hexatopic ligand btti with dicopper paddlewheel clusters. This material has rigid connectivity but a flexible framework, which has been attributed to a curvature change of the ligand.

A super-paddlewheel (comprised of two paddlewheels) metal-organic polyhedron (MOP) containing surface hydroxyl groups was synthesized and characterized. Condensation reactions with linear alkyl anhydrides lead to new MOPs with enhanced solubility. As a result, the surface-modified MOP 4 was demonstrated as a homogeneous Lewis-acid catalyst.

Cavities up to 4 nm have been introduced into a hierarchically-assembled metal-organic framework by adopting an angular, semi-flexible tetratopic ligand. The resulting MOF possesses permanent porosity and exhibits stepwise sorption isotherms for O(2) and N(2) gases.

Reactions between two novel hexatopic carboxylate ligands and copper salts give rise to two isostructural metal-organic frameworks (MOFs) with a (3,24)-connected network topology containing both micro- and mesocavities with sizes of up to 3 nm. Both frameworks retain their porosity after guest-molecule removal, leading to high surface areas. Constructing MOFs containing mesocavities with microwindows may serve as a general approach toward stable MOFs with high surface areas.

Stepwise adsorption in a metal-organic framework with both micro- and meso-pores is caused by adsorbates first filling the micropores, then adsorbing along the mesopore walls, and finally filling the mesopores.

Picky cage: A dicopper(II)-paddle-wheel-based metal-organic framework (PCN-80, see picture) with a rare (3,3,4)-connected topology has been synthesized by using a unique octatopic ligand featuring 90°-bridging-angle-dicarboxylate moieties. PCN-80 has Brunauer-Emmett-Teller (BET) and Langmuir surface areas of 3850 and 4150 m(2)  g(-1), respectively. It exhibits high gas-uptake capacity for H(2) and large adsorption selectivity of CO(2) over N(2).

A metal-organic framework (MOF) for reversible alteration of guest molecule adsorption, here carbon dioxide, upon photochemical or thermal treatment has been discovered. An azobenzene functional group, which can switch its conformation upon light irradiation or heat treatment, has been introduced to the organic linker of a MOF. The resulting MOF adsorbs different amount of CO2 after UV or heat treatment. This remarkable stimuli-responsive adsorption effect has been demonstrated through experiments.

A metal-organic framework (MOF) with helical channels has been constructed by bridging helical chain secondary building units with 2,6-di-p-carboxyphenyl-4,4'-bipyridine ligands. The activated MOF shows permanent porosity and gas adsorption selectivity. Remarkably, the MOF exhibits a facile transition from micro- to meso-porosity.

The adsorption of ten gases on the flexible metal organic framework material [Cu(dhbc)(2)(4,4'-bpy)]·H(2)O (Cu(db)) has been measured over a wide range of temperatures and pressures. The gate opening condition and driving force behind gate adsorption for Cu(db) were discussed by examining the adsorption isotherms. The adsorption isotherms for each adsorbate can be generalized to a characteristic curve using the adsorption potential energy (ε) and the adsorption volume. The adsorption potential (ε(gate)) at gate opening is almost constant over a wide range of temperatures; thus, the gate pressure at a desired temperature can be deduced using the ε(gate) evaluated from one adsorption isotherm. The gate opening capacity of the gases was arranged in the order: CO(2)≒N(2)O>C(2)H(4)≒Xe>CH(4)>CO>O(2)>Ar≒N(2)>H(2), which is governed by the interaction energy between the outer surface of Cu(db) and the adsorbate. It is suggested that the gate effect is brought about when the integral interaction energy of adsorbates with the Cu(db) surface exceeds a defined limit correlating with the π-π stacking energy of Cu(db) layers.

Three new metal-organic framework isomers have been synthesized by using the organic linker 5-triazole isophthalic acid and Mn(NO(3))(2)·xH(2)O. Structural conversions from non-porous to porous MOFs due to the template effect have been observed. The cross-sectional pore apertures of the resulting Mn-MOFs are comparable to the molecular dimensions of the template (pyrazine and 4,4'-bipyridine). The periodic increased porosity in Mn-MOFs depending on the size of the template used has been further confirmed by the CO(2) adsorption isotherms.

Although metal-organic framework (MOF) materials have been postulated as superior to any other sorbent for CO(2) adsorption at room temperature, here we prove that the appropriate selection of the raw material and the synthesis conditions allows the preparation of carbon molecular sieves (CMSs) with adsorption capacity, on a volumetric basis, highly exceeding those reported in the literature for MOFs. Furthermore, the excellent sorption properties of CMSs over the whole pressure range (up to 50 bar) are fully reversible after different adsorption/desorption cycles.

Reaction of Cr(CO)(6) with trimesic acid in DMF affords the metal-organic framework Cr(3)(BTC)(2).nDMF (BTC(3-)= 1,3,5-benzenetricarboxylate), which is isostructural to Cu(3)(BTC)(2).3H(2)O. Exchanging DMF for methanol and heating at 160 degrees C under dynamic vacuum for 48 h results in the desolvated framework Cr(3)(BTC)(2). Nitrogen gas adsorption measurements performed at 77 K revealed a type I isotherm, indicating BET and Langmuir surface areas of 1810 and 2040 m(2)/g, respectively. At 298 K, the O(2) adsorption isotherm for Cr(3)(BTC)(2) rises steeply to a capacity of 11 wt % at 2 mbar, while the corresponding N(2) adsorption isotherm displays very little uptake, gradually rising to a capacity of 0.58 wt % at 1 bar. Accordingly, the material displays an unprecedented O(2)/N(2) selectivity factor of 22. Deoxygenation of the sample could be accomplished by heating at 50 degrees C under vacuum for 48 h, leading to a gradually diminishing uptake capacity over the course of 15 consecutive adsorption/desorption cycles. Infrared and X-ray absorption spectra suggest formation of an O(2) adduct with partial charge transfer from the Cr(II) centers exposed on the surface of the framework. Neutron powder diffraction data confirm this mechanism of O(2) binding and indicate a lengthening of the Cr-Cr distance within the paddle-wheel units of the framework from 2.06(2) to 2.8(1) A.

Adsorption equilibrium and kinetics of CO(2), CH(4), N(2)O, and N(2) on two newly discovered adsorbents, metal-organic frameworks MOF-5 and MOF-177 and one traditional adsorbent, zeolite 5A were determined to assess their efficacy for CO(2), CH(4), and N(2)O removal from air and separation of CO(2) from CH(4) in pressure swing adsorption processes. Adsorption equilibrium and kinetics data for CO(2), CH(4), N(2)O, and N(2) on all three adsorbents were measured volumetrically at 298K and gas pressures up to 800 Torr. Adsorption equilibrium capacities of CO(2) and CH(4) on all three adsorbents were determined gravimetrically at 298 K and elevated pressures (14 bar for CO(2) and 100 bar for CH(4)). The Henry's law and Langmuir adsorption equilibrium models were applied to correlate the adsorption isotherms, and a classical micropore diffusion model was used to analyze the adsorption kinetic data. The adsorption equilibrium selectivity was calculated from the ratio of Henry's constants, and the adsorbent selection parameter for pressure swing adsorption processes were determined by combining the equilibrium selectivity and working capacity ratio. Based on the selectivity and adsorbent selection parameter results, zeolite 5A is a better adsorbent for removing CO(2) and N(2)O from air and separation of CO(2) from CH(4), whereas MOF-177 is the adsorbent of choice for removing CH(4) from air. However, both MOF adsorbents have larger adsorption capacities for CO(2) and CH(4) than zeolite 5A at elevated pressures, suggesting MOF-5 and MOF-177 are better adsorbents for CO(2) and CH(4) storage. The CH(4) adsorption capacity of 22 wt.% on MOF-177 at 298K and 100 bar is probably the largest adsorption uptake of CH(4) on any dry adsorbents. The average diffusivity of CO(2), CH(4) and N(2)O in MOF-5 and MOF-177 is in the order of 10(-9) m(2)/s, as compared to 10(-11) m(2)/s for CO(2), CH(4) and N(2)O in zeolite 5A. The effects of gas pressure on diffusivity for different adsorabte-adsorbent systems were also investigated.

MIL-101 is a chromium terephthalate-based mesoscopic metal-organic framework and one of the most porous materials reported to date. In this study, we investigate the adsorption of CO(2) and CH(4) in dehydrated and hydrated MIL-101 and the effect of terminal water molecules on adsorption. The atomistic structures of MIL-101 are constructed from experimental crystallographic data, energy minimization, and quantum mechanical optimization. The adsorption isotherm of CO(2) predicted from molecular simulation agrees well with experiment and is relatively insensitive to the method (Merz-Kollman or Mulliken) used to estimate the framework charges. Both the united-atom and five-site models of CH(4) predict the isotherm fairly well, though the former overestimates and the latter underestimates. Adsorption first occurs in the microporous supertetrahedra at low pressures and then in the mesoscopic cages with increasing pressure. In the dehydrated MIL-101, more adsorbate molecules are located near the exposed Cr(2) sites than the fluorine saturated Cr(1) sites. The terminal water molecules in the hydrated MIL-101 act as additional interaction sites and enhance adsorption at low pressures. This enhancement is more pronounced for CO(2) than for CH(4), because CO(2) is quadrapolar and interacts more strongly with the terminal water molecules. At high pressures, however, the reverse is observed, as the presence of terminal water molecules reduces free volume and adsorption. For the adsorption of CO(2)/CH(4) mixture, a higher selectivity is found in the hydrated MIL-101.

The synthesis and structure of Co(2)(ad)(2)(CO(2)CH(3))(2).2DMF.0.5H(2)O (bio-MOF-11) is described. Pyrimidine and amino groups of adeninate (ad) decorate the pores of the framework. The porosity of this material was studied, and its CO(2) and H(2) adsorption properties were evaluated. bio-MOF-11 exhibits a high heat of adsorption for CO(2)( approximately 45 kJ/mol), a high CO(2) capacity ( approximately 6 mmol/g, 273 K), and exceptional selectivity for CO(2) over N(2) at 273 K (81:1) and 298 K (75:1).

Zn(2+) ions react with 3,5-pyridinedicarboxylate (pydc) to form a new metal-organic framework (MOF),[Zn(pydc)(dma)](dma = N,N'-dimethylacetamide), based on a noninterpenetrating (10,3)-a topology. The framework possessing narrow one-dimensional channels is highly flexible, and as a result, guest-dependent breakthrough-like adsorptions occur under atmospheric pressure. This "gate opening" requires strong interactions between gas molecules and the adsorbent, and therefore [Zn(pydc)(dma)] shows a reverse selectivity for H(2) at 77 K, which is very unusual in MOFs. At 195 K, only CO(2) is selectively adsorbed by this material because of the temperature dependence of the gated adsorption.

Two imidazolate-metal based rhombic dodecahedra (termed MOP-100 and MOP-101) were designed and prepared from [(NH(3))(4)Pd(NO(3))(2)] and hydrogen tetrakis(1-imidazolyl)borate or hydrogen tetrakis(4-methyl-1-imidazolyl)borate in a concentrated ammonium hydroxide solution at 85 degrees C. Both rhombic dodecahedra show unusual chemical stability in acidic and basic solutions as well as common organic solvents. Permanent porosity was examined by gas adsorption studies. From the N(2) isotherm for MOP-101, the Langmuir and BET surface areas of MOP-101 were calculated to be 350 and 280 m(2) g(-1), respectively. Anion exchange experiments confirmed the internal cavities of such polyhedra are accessible.

Two novel metal coordination polymers,[Zn(5)Cl(4)(BBTA)(3)].3 DMF (), and [ZnCl(BBTA)(0.5)(DMA)](){H(2)-BBTA = 1H,5H-benzo(1,2-d:4,5-d')bistriazole}, have been synthesized under solvothermal conditions using ZnCl(2) and H(2)-BBTA in DMF (DMF = N,N'-dimethylformamide) or DMA (DMA = N,N'-dimethylacetamide). Moreover, a highly efficient microwave synthetic route has been developed for . The structures of both compounds have been determined by single crystal X-ray diffraction. Compound represents the first example of a novel family of cubic microporous metal-organic frameworks (MFU-4; Metal-Organic Framework Ulm University-4), consisting of dianionic BBTA(2-) linkers and pentanuclear {Zn(5)Cl(4)}(6+) secondary building units, whereas compound forms a dense 2D layered framework. Phase purity of both compounds was confirmed by X-ray powder diffraction (XRPD), IR spectroscopy, and elemental analysis. TGA and variable temperature XRPD (VTXRPD) experiments carried out on indicate that solvent molecules occluded in the large cavities of can be removed at a temperature >250 degrees C in high vacuum without significant loss of crystallinity, giving rise to a metal-organic framework with void cavities. Due to the small diameter of the aperture joining the two types of cavities present in , the diffusion of guest molecules across the crystal lattice is largely restricted at ambient conditions. Compound therefore exhibits a highly selective adsorption for hydrogen vs. nitrogen at -196 degrees C. The framework is stable against moisture and has a specific pore volume of 0.42 cm(3) g(-1) estimated from the water adsorption isotherm.