A Propeller-Like Ligand-Directed Construction of a Tetranuclear Cerium-Organic Framework for Single-Step Ethylene Purification from Ternary C2 Mixtures.

The efficient single-step purification of ethylene from ternary C2 mixtures containing ethane and acetylene is challenging and demanding. Herein, we introduce a novel cerium-based metal-organic framework (MOF) of Ce-NTB-rtk synthesized via a ligand-conformer strategy. The Ce-NTB-rtk features a rare tetranuclear cerium cluster and 2D kgd layers pillared by a 3D rtl framework concomitant with an extraordinary (3,3,12)-c network. The compound encompasses microporous cavities replete with a nonpolar microenvironment. Gas sorption and breakthrough experiments demonstrate its superior affinity for C2H6 and C2H2 over C2H4, enabling effective single-step ethylene purification. Computational simulations reveal that preferential adsorptions are facilitated by different interaction strengths of C-H···O hydrogen bonds. The performance of Ce-NTB-rtk in separation selectivity and regeneration capacity makes it a promising candidate for sustainable and cost-effective ethylene purification, showcasing the potential of MOFs in advanced gas separation applications.

Enhanced Selectivity in 4-Quinolone Formation: A Dual-Base System for Palladium-Catalyzed Carbonylative Cyclization with Fe(CO)5.

The use of gaseous CO in Pd-catalyzed carbonylative quinolone synthesis presents challenges related to safety and precise pressure control. In response, a streamlined non-gaseous synthesis of 4-quinolone compounds has been developed. This study introduces a tunable CO-releasing system utilizing Fe(CO)5 activated by a dual-base system of piperazine and triethylamine. This alternative liquid CO resource facilitates the palladium-catalyzed carbonylative C-C coupling and subsequent intramolecular cyclization. By tuning the tandem kinetics of carbonylation and cyclization, this non-gaseous method achieves the successful synthesis of 22 distinct 4-quinolones with excellent yields. This is achieved through the three-component condensation of sub-stoichiometric amounts of Fe(CO)5 with 2-iodoaniline and terminal alkynes. Operando mechanistic studies have revealed a novel CO transfer mechanism that facilitates homogeneous carbonylative cyclization, distinguishing this method from traditional techniques. In addition to addressing safety concerns, this approach also provides precise control over selectivity, with significant implications for pharmaceutical research and the efficient synthesis of pharmaceutical and bioactive compounds.

Polynuclear Rare-Earth Cluster-Directed Self-Assembly of Highly Porous Zeolite-like Metal-Organic Frameworks with Methane Storage Property.

Due to their intrinsic structural features, the design and synthesis of a new type of zeolite-like metal-organic frameworks (ZMOFs) is highly desirable but challenging. Herein, solvothermal reactions between an angular dicarboxylate linker and rare-earth (RE) ions afforded two RE-MOFs, namely, Tb-ZMOF-2 and Tb-ZMOF-3, respectively. Structural analyses reveal that Tb-ZMOF-2 encompasses a novel [446482] cage, while Tb-ZMOF-3 contains nonanuclear (i.e., D6R) and hexanuclear (i.e., D4R) RE clusters simultaneously, subsequently resulting in two new zeolitic topologies. Thanks to its high surface area and pore volume, Tb-ZMOF-2 demonstrates considerably high gravimetric and volumetric methane storage working capacities.

Highly Stable Amide-Functionalized Zirconium-Organic Frameworks: Synthesis, Structure, and Methane Storage Capacity.

With the development of crystalline porous materials toward methane storage, the stability issue of metal-organic framework (MOF) materials has caused great concern despite high working capacity. Considering the high stability of zirconium-based MOFs and effective functions of amide groups toward gas adsorption, herein, a series of UiO-66 type of Zr-MOFs, namely, Zr-fcu-H/F/CH3/OH, were successfully designed and synthesized by virtue of amide-functionalized dicarboxylate ligands bearing distinct side groups (i.e., -H, -F, -CH3, and -OH) and ZrCl4 in the presence of trifluoroacetic acid as the modulator. Single-crystal X-ray diffraction and topology analyses reveal that these compounds are archetypal fcu MOFs encompassing octahedral and tetrahedral cages, respectively. The N2 sorption isotherms and acid-base stability tests demonstrate that the materials possess not only relatively high surface areas, pore volumes, and appropriate pore sizes but also great hydrolytic stabilities ranging pH = 3-11. Furthermore, the volumetric methane storage working capacities of Zr-fcu-H, Zr-fcu-F, Zr-fcu-CH3, and Zr-fcu-OH at 298/273 K and 80 bar are 187/217, 175/193, 167/187, and 154/171 cm3 (STP) cm-3, respectively, which indicate that the zirconium-based crystalline porous materials are capable of storing relatively high amounts of methane.

RhB-Embedded Zirconium-Biquinoline-Based MOF Composite for Highly Sensitive Probing Cr(VI) and Photochemical Removal of CrO42-, Cr2O72-, and MO.

How to accurately detect and efficiently sweep Cr(VI) from contaminated water has come into focus. Zirconium-based metal-organic frameworks (MOFs) play vital roles in water environmental chemistry due to excellent hydrolysis-resistant stability. However, as photochemical probes and photocatalysts, poor performances in detection sensitivity, selectivity, and photosensitiveness limit sole Zr-MOFs' applications. So, it is urgent to quest valid strategies to break through the dilemmas. Embedding luminous dyes into MOFs has been considered one of the most feasible avenues. Herein, a dual-emissive RhB@Zr-MOF with orange-yellow fluorescence has been assembled by in situ-encapsulating rhodamine B (RhB) into a zirconium-biquinoline-based MOF. Actually, within RhB@Zr-MOF, the aggregation fluorescence quenching (ACQ) effect of RhB molecules was effectively avoided. Notably, RhB@Zr-MOF exhibits a rapid fluorescence quenching response toward Cr(VI) ions with high selectivity, sensitivity, and anti-interference abilities. More interestingly, unlike the most widely reported fluorescence resonance energy transfer (FRET) between MOFs and encapsulated guest modules, photoinduced electron transfer from RhB to Zr-MOF has been confirmed by modeling the ground state and excited states of RhB@Zr-MOF using density functional theory (DFT) and time-dependent DFT (TD-DFT). The effective electron transfer makes RhB@Zr-MOF more sensitive in probing Cr2O72- and CrO42- ions with ultralow detection limit (DL) values of 6.27 and 5.26 ppb, respectively. Prominently, the detection sensitivity based on DL values has been increased about 6 and 9 times, respectively, compared with pristine Zr-MOF. Moreover, rather negative CB and positive VB potentials make RhB@Zr-MOF have excellent photochemical scavenging ability toward Cr(VI) and MO.

New Reticular Chemistry of the Rod Secondary Building Unit: Synthesis, Structure, and Natural Gas Storage of a Series of Three-Way Rod Amide-Functionalized Metal-Organic Frameworks.

Reticular chemistry and methane storage materials have been predominately focused on finite metal-cluster-based metal-organic frameworks (MOFs). In contrast, MOFs constructed from infinite rod secondary building units (SBUs), i.e., rod MOFs, are less developed, and the existing ones are typically built from simple one-way helical, zigzag, or (mixed)polyhedron SBUs. Herein, inspired by a recent unveiled structure of Zn6(H2O)3(BTP)4 and by means of an amide-functionalized preliminary single tricarboxylate, a subsequent mixed tricarboxylate, and dicarboxylate linkers, an intricate three-way rod MOF and the next three isoreticular three-way rod MOFs have been successfully realized, namely, 3W-ROD-1 and 3W-ROD-2-X (X = -OH, -F, and -CH3), respectively. The structural analyses disclosed that the four compounds were constructed from unprecedented three-way invariant nonintersecting trigonal rod-packing SBUs cross-linked via the noncovalent-interaction-driven self-assembly of pseudo hexacarboxylates with the original tricarboxylate or different functional ditopic linkers, resulting in cage-like pore geometries accessible via ultramicroporous apertures concomitant with the complex topology transitivity, namely, 18 42 and 18 44. Sorption studies show that the apparent surface areas of these materials are among the most highly porous materials for rod MOFs. Due to the presence of favorable pocket sites created by X, ketone, and proximal amide groups as revealed by Monte Carlo molecular dynamics (MCMD) computational calculations, the MOFs exhibit impressive methane storage working capacities, outperforming the well-known rod Ni-MOF-74 and representing the highest values among rigid rod MOFs.

Hydrolytically Stable and Trifunctional Zirconium-Based Organic Frameworks toward Cr2O72- Detection, Capture, and Photoreduction.

Chromium Cr(VI) is frequently used in many fields and has been intensively researched for detection and/or removal from contaminated water. However, the existing approaches are still of low efficiency, high cost, and cumbersome in operation. It is thus highly imperative to hunt for alternative avenues to get out of the predicament. In this work, two bcu topological and highly stable zirconium-metal-organic frameworks (Zr-MOFs) of 1 and 2 have been deliberately prepared, displaying channel-type interior spaces replete with free bipyridine/biquinoline matrices and Zr-O defect sites. Because of their unique intrinsic features of high porosity and photosensitivity, 1 and 2 were deployed as versatile platforms to sense, adsorb, and catalytically reduce Cr(VI) ions. Indeed, the Zr-MOF of 1 performs excellently in fluorescence sensing and adsorption trapping of Cr(VI), with an ultralow detection limit of 0.0176 ppm and a fairly high saturated adsorption capacity of 145.77 mg/g, while 2 is more powerful than 1 in photochemical removal of Cr(VI), exhibiting a remarkable reduction efficiency of 98.05% just within 70 min and still up to 92.21% even after five consecutive photocatalytic cycles. Furthermore, possible photoluminescence, quenching, and reduction mechanisms were also tentatively proposed. This study may open up a new avenue for addressing some unresolved environmental issues, that is, the decontamination of highly toxic Cr(VI) from water.

Ligand-Conformer-Induced Formation of Zirconium-Organic Framework for Methane Storage and MTO Product Separation.

In pursuit of novel adsorbents with efficient adsorptive gas storage and separation capabilities remains highly desired and challenging. Although the documented zirconium-tricarboxylate-based metal-organic frameworks (MOFs) have displayed a variety of topologies encompassing underlying and geometry mismatch ones, the employed organic linkers are exclusively rigid and poorly presenting one type of conformation in the resultant structures. Herein, a used and semirigid tricarboxylate ligand of H3 TATAB was judiciously selected to isolate a zirconium-based spe-MOF after the preliminary discovery of srl-MOF. Single-crystal X-ray diffraction reveals that the fully deprotonated TATAB linker in spe-MOF exhibits two distinct conformers, concomitant with popular Oh and rare S6 symmetrical Zr6 molecular building blocks, generating an unprecedented (3,3,12,12)-c nondefault topology. Specifically, the spe-MOF exhibits structurally higher complexity, hierarchical micropores, open metal sites free and rich electronegative groups on the pore surfaces, leading to relatively high methane storage capacity without considering the missing-linker defects and efficient MTO product separation performance.

Single-Crystal Synthesis and Diverse Topologies of Hexanuclear CeIV-Based Metal-Organic Frameworks.

CeIV6-based metal-organic frameworks (MOFs) have gained increasing attention recently because of their diverse potential applications and similarity to prominent Zr-MOFs, e.g., the UiO-66 series. However, the reported CeIV6-based MOFs were all structurally determined by means of the powder X-ray diffraction technique, indicative of less practice and convenience. Herein, four single-crystalline CeIV6-based MOFs were successfully isolated and characterized by single-crystal X-ray diffraction, disclosing two series of topologically distinct isoreticular nets accompanied by nine-coordinated central CeIV ions, i.e., 8-connected hex and 12-connected fcu, respectively, in contrast to the previously reported sole fcu topology based on the combination of linear dicarboxylate ligands and a CeIV6 cluster associated with eight-coordinated central CeIV ions according to the UiO-66 structural model. Moreover, all four single-crystalline compounds exhibit permanent microporous porosities and a certain amount of gas uptake toward CO2, CH4, and H2.

Enriching the Reticular Chemistry Repertoire: Merged Nets Approach for the Rational Design of Intricate Mixed-Linker Metal-Organic Framework Platforms.

Rational design and construction of metal-organic frameworks (MOFs) with intricate structural complexity are of prime importance in reticular chemistry. We report our latest addition to the design toolbox in reticular chemistry, namely the concept of merged nets based on merging two edge-transitive nets into a minimal edge-transitive net for the rational construction of intricate mixed-linker MOFs. In essence, a valuable net for design enclosing two edges (not related by symmetry) is rationally generated by merging two edge-transitive nets, namely (3,6)-coordinated spn and 6-coordinated hxg. The resultant merged-net, a (3,6,12)-coordinated sph net with net transitivity [32] enclosing three nodes and two distinct edges, offers potential for deliberate design of intricate mixed-linker MOFs. We report implementation of the merged-net approach for the construction of isoreticular rare-earth mixed-linker MOFs, sph-MOF-1 to -4, based on the assembly of 12-c hexanuclear carboxylate-based molecular building blocks (MBBs), displaying cuboctahedral building units, 3-c tritopic ligands, and 6-c hexatopic ligands. The resultant sph-MOFs represent the first examples of MOFs where the underlying net is merged from two 3-periodic edge-transitive nets, spn and hxg. Distinctively, the sph-MOF-3 represents the first example of a mixed-linker MOF to enclose both trigonal and hexagonal linkers. The merged-nets approach allows the logical practice of isoreticular chemistry by taking into account the mathematically correlated dimensions of the two ligands to afford the deliberate construction of a mixed-linker mesoporous MOF, sph-MOF-4. The merged-net equation and two key parameters, ratio constant and MBB constant, are disclosed. A merged-net strategy for the design of mixed-linker MOFs by strictly controlling the size ratio between edges is introduced.

Applying the Power of Reticular Chemistry to Finding the Missing alb-MOF Platform Based on the (6,12)-Coordinated Edge-Transitive Net.

Highly connected and edge-transitive nets are of prime importance in crystal chemistry and are regarded as ideal blueprints for the rational design and construction of metal-organic frameworks (MOFs). We report the design and synthesis of highly connected MOFs based on reticulation of the sole two edge-transitive nets with a vertex figure as double six-membered-ring (d6R) building unit, namely the (4,12)-coordinated shp net (square and hexagonal-prism) and the (6,12)-coordinated alb net (aluminum diboride, hexagonal-prism and trigonal-prism). Decidedly, the combination of our recently isolated 12-connected (12-c) rare-earth (RE) nonanuclear [RE9(µ3-OH)12(µ3-O)2(O2C-)12] carboxylate-based cluster, points of extension matching the 12 vertices of hexagonal-prism d6R, with 4-connected (4-c) square porphyrinic tetracarboxylate ligand led to the formation of the targeted RE-shp-MOF. This is the first time that RE-MOFs based on 12-c molecular building blocks (MBBs), d6R building units, have been deliberately targeted and successfully isolated, paving the way for the long-awaited (6,12)-c MOF with alb topology. Indeed, combination of a custom-designed hexacarboxylate ligand with RE salts led to the formation of the first related alb-MOF, RE-alb-MOF. Intuitively, we successfully transplanted the alb topology to another chemical system and constructed the first indium-based alb-MOF, In-alb-MOF, by employing trinuclear [In3(µ3-O)(O2C-)6] as the requisite 6-connected trigonal-prism and purposely made a dodecacarboxylate ligand as a compatible 12-c MBB. Prominently, the dodecacarboxylate ligand was employed to transplant shp topology into copper-based MOFs by employing the copper paddlewheel [Cu2(O2C-)4] as the complementary square building unit, affording the first Cu-shp-MOF. We revealed that highly connected edge-transitive nets such shp and alb are ideal for topological transplantation and deliberate construction of related MOFs based on minimal edge-transitive nets.

Tunable Rare Earth fcu-MOF Platform: Access to Adsorption Kinetics Driven Gas/Vapor Separations via Pore Size Contraction.

Reticular chemistry approach was successfully employed to deliberately construct new rare-earth (RE, i.e., Eu(3+), Tb(3+), and Y(3+)) fcu metal-organic frameworks (MOFs) with restricted window apertures. Controlled and selective access to the resultant contracted fcu-MOF pores permits the achievement of the requisite sorbate cutoff, ideal for selective adsorption kinetics based separation and/or molecular sieving of gases and vapors. Predetermined reaction conditions that permitted the formation in situ of the 12-connected RE hexanuclear molecular building block (MBB) and the establishment of the first RE-fcu-MOF platform, especially in the presence of 2-fluorobenzoic acid (2-FBA) as a modulator and a structure directing agent, were used to synthesize isostructural RE-1,4-NDC-fcu-MOFs based on a relatively bulkier 2-connected bridging ligand, namely 1,4-naphthalenedicarboxylate (1,4-NDC). The subsequent RE-1,4-NDC-fcu-MOF structural features, contracted windows/pores and high concentration of open metal sites combined with exceptional hydrothermal and chemical stabilities, yielded notable gas/solvent separation properties, driven mostly by adsorption kinetics as exemplified in this work for n-butane/methane, butanol/methanol, and butanol/water pair systems.

Ultra-Tuning of the Rare-Earth fcu-MOF Aperture Size for Selective Molecular Exclusion of Branched Paraffins.

Using isoreticular chemistry allows the design and construction of a new rare-earth metal (RE) fcu-MOF with a suitable aperture size for practical steric adsorptive separations. The judicious choice of a relatively short organic building block, namely fumarate, to bridge the 12-connected RE hexanuclear clusters has afforded the contraction of the well-defined RE-fcu-MOF triangular window aperture, the sole access to the two interconnected octahedral and tetrahedral cages. The newly constructed RE (Y(3+) and Tb(3+)) fcu-MOF analogues display unprecedented total exclusion of branched paraffins from normal paraffins. The resultant window aperture size of about 4.7 Å, regarded as a sorbate-size cut-off, enabled a complete sieving of branched paraffins from normal paraffins. The results are supported by collective single gas and mixed gas/vapor adsorption and calorimetric studies.

Tunable rare-earth fcu-MOFs: a platform for systematic enhancement of CO2 adsorption energetics and uptake.

A series of fcu-MOFs based on rare-earth (RE) metals and linear fluorinated/nonfluorinated, homo/heterofunctional ligands were targeted and synthesized. This particular fcu-MOF platform was selected because of its unique structural characteristics combined with the ability/potential to dictate and regulate its chemical properties (e.g., tuning of the electron-rich RE metal ions and high localized charge density, a property arising from the proximal positioning of polarizing tetrazolate moieties and fluoro-groups that decorate the exposed inner surfaces of the confined conical cavities). These features permitted a systematic gas sorption study to evaluate/elucidate the effects of distinctive parameters on CO2-MOF sorption energetics. Our study supports the importance of the synergistic effect of exposed open metal sites and proximal highly localized charge density toward materials with enhanced CO2 sorption energetics.

Desolvation-Degree-Induced Structural Dynamics in a Rigid Cerium-Organic Framework Exhibiting Tandem Purification of Ethylene from Acetylene and Ethane.

Due to the industrial requirements for high production and high quality of ethylene, efficient purification of ethylene from acetylene and ethane is of prime importance but challenging. Dynamic metal-organic frameworks (MOFs) have demonstrated intriguing structural dynamics and diverse applications recently. Among them, although a few flexible ones have exhibited interesting ethylene purification capability, rigid ones were yet barely investigated for such purpose. In this regard, a cerium(III)-based MOF was solvothermally synthesized, which is rigid and assembled from rod molecular building blocks associated with coordinative N,N-dimethylformamide (DMF) molecules. After liberating different degrees of DMF ligands via heating under vacuum or acetone exchange, both partially desolvated compounds of Ce-MOF-1 and Ce-MOF-2 were concertedly isolated in a fashion of single-crystal to single-crystal transformation. Although both newly generated materials crystallize in the same space group, they exhibit dissimilar unit cell parameters and slightly distinct ultramicropore sizes and pore microenvironments, thanks to the discrepancy in the desolvation degree. Consequently, Ce-MOF-1 and Ce-MOF-2 individually demonstrate C2H2- and C2H6-selective adsorption behavior, resulting in the potential tandem separation of C2H4 from C2H2 and C2H6 mixtures. The above results were successfully supported by not only single gas adsorption isotherms but also grand canonical Monte Carlo (GCMC) calculation studies and dynamic breakthrough experiments. The present work may pave the way for rigid MOFs aiming at advancing applications via solid-state structural dynamics.

Tuning Open Metal Site-Free ncb Type of Metal-Organic Frameworks for Simultaneously High Gravimetric and Volumetric Methane Storage Working Capacities.

The design and synthesis of a single metal-organic framework (MOF) material with simultaneously high gravimetric and volumetric methane storage working capacities are still a great challenge. The open metal site (OMS) in MOFs is generally regarded as an advantage to enhance host-guest affinity. However, it is detrimental to the methane storage working capacity to some extent due to the resulting high low-pressure uptake. Moreover, the reported methane storage MOFs are predominately focusing on edge-transitive or low-connected mixed-linker networks. In contrast, high-connected mixed-linker MOFs have been less investigated for methane storage. Herein, three isoreticular nine-connected trinuclear iron-based Fe-ncb-MOFs without OMSs have been judiciously designed and successfully constructed by means of the mixed-linker approach associated with the fixing amide-functionalized pyridyl-carboxylate ligand LP (4-(pyridin-4-ylcarbamoyl)benzoate) and three differing sized dicarboxylate ligands. High-pressure methane adsorption measurements show that, with the isoreticular extension from BDC (1,4-benzenedicarboxylate) to BPDC (4,4'-biphenyldicarboxylate) and ABDC (azobenzene-4,4'-dicarboxylate), three Fe-ncb-MOFs exhibit gradually increasing not only gravimetric but also volumetric storage capacities because of their balancing gravimetric surface area and volumetric surface area, hierarchical pore system, and modest CH4 heats of adsorption. Among them, the Fe-ncb-ABDC demonstrates a rare combination of simultaneously high gravimetric and volumetric CH4 storage working capacities of 0.302/0.37 g g-1 and 196/240 cm3 (STP) cm-3 at 298/273 K and between 80 and 5 bar, respectively, which outperform the 8-c Fe-8T18-ABDC assembled from a shorter pyridyl-carboxylate ligand IN (isonicotinate) and ABDC, due to its limited pore volume, the presence of OMSs, and more confined pore spaces, and place Fe-ncb-ABDC among the best performing MOFs.

The microstructure of secondary lymphoid organs that support immune cell trafficking.

Immune cell trafficking in the secondary lymphoid organs is crucial for an effective immune response. Recirculating T cells constantly patrol not only secondary lymphoid organs but also the whole peripheral organs. Thoracic duct lymphocytes represent an ideal cell source for analyzing T cell trafficking: high endothelial venules (HEVs) allow recirculating lymphocytes to transmigrate from the blood directly, and recirculating T cells form a cluster with dendritic cells (DCs) to survey antigen invasions even in a steady state. This cluster becomes an actual site for the antigen presentation when DCs have captured antigens. On activation, effector and memory T cells differentiate into several subsets that have different trafficking molecules and patterns. DCs also migrate actively in a manner depending upon their maturational stages. Danger signals induce the recruitment of several DC precursor subsets with different trafficking patterns and functions. In this review, we describe general and specialized structures of the secondary lymphoid organs for the trafficking of T cells and DCs by a multicolor immunoenzyme staining technique. The lymph nodes, spleen, and Peyer's patches of rats were selected as the major representatives. In vivo trafficking of subsets of T cells and DCs within these organs under steady or emergency states are shown and discussed, and unsolved questions and future prospects are also considered.

Porous manganese(II) 3-(2-pyridyl)-5-(4-pyridyl)-1,2,4-triazolate frameworks: rational self-assembly, supramolecular isomerism, solid-state transformation, and sorption properties.

Reactions of 3-(2-pyridyl)-5-(4-pyridyl)-1,2,4-triazole (Hdpt24) with Mn(OAc)(2) under different conditions give two mononuclear complexes, [Mn(dpt24)(2)(MeOH)(2)] (1) and [Mn(dpt24)(2)(H(2)O)(2)] x 6 H(2)O (2), and three isomeric two-dimensional (2D) coordination polymers alpha-[Mn(dpt24)(2)] (3a), beta-[Mn(dpt24)(2)] x g (3b x g, g = DMF and H(2)O), and gamma-[Mn(dpt24)(2)] x g (3c x g, g = toluene and MeOH). Their structures were characterized by single-crystal and powder X-ray diffractions. In these compounds, four coordination sites of each octahedrally coordinated Mn(II) ion are chelated by two dpt24 ligands in the trans and/or cis configurations. While the two remaining coordination sites are occupied by solvent molecules in 1 and 2, they are occupied by pyridyl nitrogens from neighboring Mn(dpt24)(2) units in 3, forming 4-connected 2D (4,4) networks. The Mn(II) ions in both 3a and 3b are uniquely chelated by dpt24 in the trans or cis configurations, respectively, but Mn(dpt24)(2) in 3c possesses both the trans and cis configurations. The packing fashions of these (4,4) layers in the three isomers of 3 are also different, in which 3a has a close packing structure, while 3b exhibits unique one-dimensional (1D) channels and 3c exhibits two distinct types of 1D channels. As revealed by powder X-ray diffractions, crystals of 1 and 2 can reversibly transform to each other when in contact with the corresponding solvent vapor (H(2)O/MeOH). The gas and vapor sorption studies for porous 3b revealed interesting sorption behaviors. Nitrogen adsorption for 3b was observed at 195 K rather than 77 K, demonstrating the temperature-controlled framework flexibility. It also exhibited high selectivity and storage capacity for carbon dioxide over methane and nitrogen at room temperature. Moreover, 3b also demonstrated potential to separate organic chemicals with similar boiling points, such as benzene and cyclohexane, via pressure swing adsorption process.

Syntheses, Structures and Sorption Properties of Three Isoreticular Trinuclear Indium-Based Amide-Functionalized Metal-Organic Frameworks.

Amide-functionalized metal-organic frameworks (AFMOFs) as a subclass of MOF materials have received great interest recently because of their intriguing structures and diverse potential applications. In this work, solvothermal reactions between indium nitrate and two mixed-linkers afforded two new isoreticular 8-connected trinuclear indium-based AFMOFs of [(In3 O)(OH)(L2)2 (IN)2 ]⋅(solv)x (2-In) and [(In3 O)(OH)(L2)2 (AIN)2 ]⋅(solv)x (NH2 -2-In) (H2 L2=4,4'-(carbonylimino)dibenzoic acid and HIN=isonicotinic acid or HAIN=3-aminoisonicotinic acid), respectively. Moreover, by means of reticular chemistry, an extended network of [(In3 O)(OH)(L3)2 (PB)2 ]⋅(solv)x (3-In) (H2 L3=4,4'-(terephthaloylbis(azanediyl))dibenzoic acid, HPB=4-(4-pyridyl)benzoic acid) was also successfully realized after prolongation of the former dicarboxylate linker and HIN, resulting in a truly 8-connected isoreticular AFMOF platform. These frameworks were structurally determined by single-crystal X-ray diffraction (SCXRD). Sorption studies further demonstrate that 2-In and NH2 -2-In exhibit not only high surface areas and pore volumes but also relatively high carbon capture capabilities (the CO2 uptakes reach 60.0 and 75.5 cm3 g-1 at 298 K and 760 torr, respectively) due to the presences of amide and/or amine functional groups. The selectivity of CO2 /N2 and CO2 /CH4 calculated by IAST are 10.18 and 12.43, 4.20 and 4.23 for 2-In and NH2 -2-In, respectively, which were additionally evaluated by mixed-gases dynamic breakthrough experiments. In addition, high-pressure gas sorption measurements show that both materials could take up moderate amounts of natural gas.

Single-crystal-to-single-crystal transformation involving release of bridging water molecules and conversion of chain helicity in a chiral three-dimensional metal-organic framework.

An unprecedented release of the bridging aqua molecules and conversion of chain helicity within a 3-D chiral cadmium(ii) dicarboxylate coordination polymer was observed in a unique and drastic single-crystal-to-single-crystal transformation of dehydration.