The design and construction of "thermodynamically stable" metal-organic frameworks (MOFs) that can survive in liquid water,b oiling water,a nd acidic/basic solutions over aw ide pH range is highly desirable for many practicala pplications, especially adsorption-based gas separationsw ith obviouss calablep reparations. Herein,anew thermodynamically stable Ni MOF,{ [Ni(L)(1,4-NDC)(H 2 O) 2 ]} n (IITKGP-20;L= 4,4'-azobispyridine;1 ,4-NDC = 1,4-naphthalene dicarboxylic acid;I ITKGP stands for the Indian Institute of Technology Kharagpur), hasb een designed that displays moderate porosity with aB ET surfacea rea of 218 m 2 g À1 and micropores along the [10À1] direction. As an alternative to ac ost-intensive, cryogenic,h igh-pressure distillation process for the separation of hydrocarbons, MOFsh ave recently shown promise for such separations. Thus, towards an application standpoint, this MOF exhibits ah igher uptake of C 2 hydrocarbons over that of C 1 hydrocarbon under ambient conditions, with one of the highest selectivities basedo nt he ideal adsorbed solution theory (IAST)m ethod. Ac ombination of two strategies (the presence of stronger metal-N coordinationo ft he spacera nd the hydrophobicity of the aromatic moiety of the organic ligand) possibly makes the framework highly robust, even stable in boiling water and over aw ide range of pH 2-10, andr epresents the first example of at hermodynamically stableM OF displayinga2D structural network. Moreover, this material is easily scalable by heatingt he reaction mixture at reflux overnight. Because such separations are performedi nt he presence of water vapor and acidic gases, there is ag reat need to explore thermodynamically stable MOFs that retain not only structurali ntegrity,b ut also the porosityo ft he frameworks.
Two 3D luminescent Cd(ii) MOFs (Cd-MOF-1 and Cd-MOF-2) exposing azo functional sites displayed selective detection of Fe3+ and Al3+ metal ions with high sensitivities.
In recent years, heterogeneous catalysis has become one of the most active domains in the research of metal−organic frameworks (MOFs). Here, two three-dimensional (3D) Co(II)-MOFs with open metal sites and exposed azo functionality on the MOF backbone have been constructed via mixed ligand assembly. Both the MOFs,4-naphthalene dicarboxylic acid, fma = fumaric acid, L = 3,3′-azobis pyridine and S = disordered solvents] exhibit 3D frameworks with metal-bound aqua ligands. These metal-bound aqua ligands, as well as the lattice solvent molecules, could simply be removed upon activation affording the desolvated frameworks 1a and 2a respectively maintaining the original crystallinity with a varying number of open metal sites. Although crystallographic analysis revealed a porous structure for both the MOFs (34.4% and 14.3% void volume for 1 and 2, respectively), 1 showed a permanently microporous nature with a Brunauer−Emmett−Teller surface area of 197 m 2 g −1 and moderate CO 2 uptake capacity as established through a gas sorption study. Both MOFs exhibit efficient catalytic activity for the chemical fixation of CO 2 to cyclic carbonate in the presence of a cocatalyst, cyanosilylation reaction, and Knoevenagel condensation under solvent-free and mild conditions and thus demonstrating their multipurpose heterogeneous catalytic nature. The limited pore space decorated with the exposed metal sites and the functional azo groups were efficient for size-selective heterogeneous catalysis with varying catalytic efficiencies. A systematic comparison in their catalytic performances could be made with the establishment of a structure−function relationship. Besides, both MOFs can easily be separated out from the reaction mixtures and reused for at least four cycles without any loss of catalytic activity and structural integrity.
TPVs are prepared by dynamic vulcanization in which crosslinking of an elastomeric polymer takes place during its melt mixing with a thermoplastic polymer under high‐shear conditions. 30:70 wt% blends of PP and ethylene–octene copolymer are vulcanized using electron‐induced reactive processing (EIReP) employing a range of absorbed doses (25, 50, and 100 kGy) while keeping the electron energy and treatment time fixed. The structure/property relationships of the prepared samples are studied using various characterization techniques such as DMA, DSC, SEM, and melt rheology. The results suggest that EIReP offers a novel route to prepare TPVs without any chemical crosslinking and coupling agents.
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