Development of active porous materials that can efficiently adsorb H and CO is needed, due to their practical utilities. Here we present the design and synthesis of an interpenetrated Cu metal-organic framework (MOF) that is thermally stable, highly porous and can act as a heterogeneous catalyst. The Cu -MOF contains a highly symmetric polyhedral metal cluster (Cu ) with cuboctahedron geometry as secondary building unit (SBU). The double interpenetration of such huge cluster-containing nets provides a high density of open metal sites, due to which it exhibits remarkable H storage capacity (313 cm g at 1 bar and 77 K) as well as high CO capture ability (159 cm g at 1 bar and 273 K). Further, its propensity towards CO sorption can be utilized for the heterogeneous catalysis of the chemical conversion of CO into the corresponding cyclic carbonates upon reaction with epoxides, with high turnover number and turnover frequency values.

Switchable metal-organic frameworks change their structure in time and selectively open their pores adsorbing guest molecules, leading to highly selective separation, pressure amplification, sensing and actuation applications. The three-dimensional engineering of metal-organic frameworks has reached a high level of maturity, but spatiotemporal evolution opens a new perspective towards engineering materials in the 4 th dimension (time) by t-axis design, in essence exploiting the deliberate tuning of activation barriers. This work demonstrates the first example in which an explicit temporal engineering of a switchable metal-organic frameworkdeliberately tuned by variation of cobalt content. We present a spectrum of advanced analytical methods for analyzing the switching kinetics stimulated by vapor adsorption using in situ time resolved techniques ranging from ensemble adsorption and advanced synchrotron X-ray diffraction experiments to individual crystal analysis. A novel analysis technique based on microscopic observation of individual crystals in a microfluidic channel reveals the lowest limit for adsorption switching reported so far. The time constants for the bulk ensembles range from 2 -300 s. Differences in spatiotemporal response of crystal ensembles originate from a delay (induction) time that varies statistically and widens characteristically with increasing cobalt content reflecting increasing activation barriers.

A rarely porous Li-MOF (Li-AOIA) with surface area of 605 m2/g was employed for the formation of an emerging class of solvent free, solid electrolytes. Infiltration of LiBF4 into Li-AOIA...

Development of an efficient and inexpensive water oxidation electrocatalyst using the earth-abundant elements is still far to go. Herein, a novel strategy has been demonstrated for developing the OER electrocatalyst by doping Co(II) in to a three-dimensional Cd-based MOF that contains a naked pyridine moieties in the form of uncoordinated ligand. Electrochemically active CoCd-MOF was resulted through the doping of Co(II) into the inactive Cd-MOF. CoCd-MOF exhibited very high catalytic activity in water oxidation reaction. An overpotential of 353 mV is required to produce an anodic current density of 1 mA/cm under alkaline conditions. Further, the CoCd-MOF exhibits remarkable recyclability over 1000 cycles.

A new covalent organic framework (COF) based on imine bonds was assembled from 2-(4-formylphenyl)-5-formylpyridine and 1,3,6,8-tetrakis(4-aminophenyl)pyrene, which showed an interesting dual-pore structure with high crystallinity. Postmetallation of the COF with Pt occurred selectively at the N donor (imine and pyridyl) in the larger pores. The metallated COF served as an excellent recyclable heterogeneous photocatalyst for decarboxylative difluoroalkylation and oxidative cyclization reactions.

The dye encapsulated metal–organic frameworks (MOFs) are of interest for their practical applications such as light-emitting diodes, temperature sensing, and microlasers. However, very few MOFs have been reported to date where the dye moiety is utilized as one of the components of the framework. Fluorescein dye (FSD) doped materials have an ability to emit various colors such as red, green, and yellow depending upon their tautomeric form and external stimuli. In anticipation of light-emitting devices, three FSD-based novel MOFs, namely, {[Co2(FSD)2(H2O)4]·H2O·MeOH} n , FSDCo; {[Mn2(FSD)2(H2O)4]·H2O·MeOH} n , FSDMn; and {[Cd2(FSD)2(H2O)3(MeOH)]·2­(H2O)} n , FSDCd, have been designed and synthesized. These crystalline materials were shown to exhibit multicolor light-emitting behavior and reversible green to brown piezochromism, implying their potential to act as fluorescent switches, mechanosensors, and security papers. Further, these crystalline MOFs were also shown to exhibit a rare optical phenomenon called pleochroism. The green colored crystals displayed multiple colors under polarized light due to the agglomeration of nano- and microcrystals at different angles on the surface of macrocrystals.

A 3D-coordination polymer was shown to trap one-dimensional polyhedral water cages consisting of repeat units of IJH 2 O) 24 , the geometry of which resembles the exotic organic molecule pagodane. Further, this material exhibited proton conduction ability and tunable luminescence emission by adsorption of anionic dyes such as the fluorescein dianion.In recent years special attention has been paid to the design and synthesis of microporous materials, in particular, metalorganic frameworks (MOFs) or covalent organic frameworks (COFs) for gas storage and separation purposes. 1 These materials contain well-defined pores and possess the ability to incorporate several guest molecules and assemblies of guest molecules which otherwise can't be realized. 2 For example, a variety of water clusters with different sizes and shapes have been reported in the past which afford some information related to the anomalous behaviour of bulk water, but it is still a little understood liquid. 3 On the other hand, infinite chains of water molecules, hydrogen bonded water clusters and metal-coordinated water molecules have been shown to have a potential to act as proton carriers under humid as well as anhydrous conditions. 4 Proton-conducting materials are of importance for developing electrochemical cells such as fuel cells, electrochemical sensors, electrochemical reactors, and electrochromic devices. Fuel cells are thought to be one of the alternative energy sources for the next generation. 5,6 Proton conductivity can mediate the process of conversion of energy from one form into another by involving the transfer of protons in proton exchange membrane fuel cells (PEMFCs) where the proton conducting materials are being used as the membrane electrolyte. Proton conduction within a hydrogenbonded water cluster is anticipated with the formation of H 3 O + within the network where the transfer of a proton occurs with a simultaneous rearrangement between nearby H 2 O molecules following the Grotthuss or proton-hopping mechanism. 7,8 In MOFs and COFs, the hydrophobic nature of the channels/cavities can be effectively tailored toward a hydrophilic nature by introducing functional groups that are capable of forming hydrogen bonds to the backbone of the linear exobidentate ligands. The organic backbone in MOFs serves as an anchor for the inclusion and self-organization of free water molecules into various ordered aggregates via hydrogen bonding. 9 To date, several varieties of water clusters consisting of discrete assemblies such as tetramers, pentamers, hexamers, octamers, decamers and polyhedral cages, one-dimensional chains and helices and twodimensional layers have been identified in the crystal lattices of MOFs. 10 However, to the best of our knowledge no onedimensional polyhedral cage structure of water molecules was reported to date. Herein, we report one such example of a 3D-coordination polymer (CP) containing one-dimensional water cages with a repeat unit of IJH 2 O) 24 , the geometry of which resembles the organic molecule pagodane. ...

The role of anions in the formation of diversified coordination polymers (CPs) of a flexible bidentate ligand (L), containing an aliphatic-aromatic spacer (p-xylyl) between amidopyridine moieties, has been explored. The reaction of L with Cd(II) or Cu(II) salts of NO 3 − , ClO 4 − , SO 4 2− , and SiF 6 2− resulted in the single crystals of eight CPs. The X-ray diffraction analyses of the single crystals reveal that the CPs contain 1D-zigzag (SiF 6 2− ), open (4,4)-network (NO 3 − and SCN − ), and the interpenetrated 2D-networks with (4,4)-and (6,3)topologies and pseudodiamondoid network (SO 4 2− and ClO 4 −). These results clearly indicate that the presence of tetrahedral anions favored the interpenetration of the 2D-and 3D-networks. The resultant cationic CPs are explored for their dye adsorption ability based on the charge transfer interaction between the framework and ionic dye. Among all CPs, complex 8 containing a 3D-interpenetrated diamondoid network was found to show remarkable ability for the uptake of anionic dyes such as fluorescein dianion (FSD) and methyl orange (MO). The ability of 8 to selectively adsorb anionic dye was utilized for the separation of the MO from cationic dye such as methylene blue. Further, the FSD adsorbed material of 8 was shown to exhibit enhanced luminescence properties.