Development of active porous materials that can efficiently adsorb H2 and CO2 is needed, due to their practical utilities. Here we present the design and synthesis of an interpenetrated CuII ...metal‐organic framework (MOF) that is thermally stable, highly porous and can act as a heterogeneous catalyst. The CuII‐MOF contains a highly symmetric polyhedral metal cluster (Cu24) 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 H2 storage capacity (313 cm3g−1 at 1 bar and 77 K) as well as high CO2 capture ability (159 cm3g−1 at 1 bar and 273 K). Further, its propensity towards CO2 sorption can be utilized for the heterogeneous catalysis of the chemical conversion of CO2 into the corresponding cyclic carbonates upon reaction with epoxides, with high turnover number and turnover frequency values.
Gas affinity: The reported CuII‐MOF contains a highly symmetric polyhedral metal cluster (Cu24) as secondary building unit (SBU). The double interpenetration provides a high density of open metal sites, due to which it exhibits remarkable H2 storage capacity as well as high CO2 capture ability. It can also catalyse CO2 fixation into cyclic carbonates.
The synthesis of reversible oligomer/polymers is fascinating both from the perspective of the fundamental understanding as well as their applications, ranging from biomedical to self‐healing smart ...materials. On the other hand, the reactions that occur in single‐crystal‐to‐single‐crystal (SCSC) fashion offer great details of the structure, geometry and stereochemistry of the product. However, SCSC 2+2 oligomerization is rather difficult and rare. Further, till date there are no reports for a reversible 2+2 oligomerization in SCSC fashion. In this work, four halogen‐substituted acrylic dienone molecules were deliberately designed and their ability to participate in 2+2 cycloaddition reaction in solid state was studied under visible light. Despite of having the required alignment of double bonds of dienes in all four crystal structures, they were found to exhibit variable reactivities given the differences in their weak intermolecular interactions such as halogen⋅⋅⋅halogen, halogen⋅⋅⋅π and C−H⋅⋅⋅O interactions. Notably, one of these materials exhibits reversible oligomerization in a SCSC manner.
The first single‐crystal‐to‐single‐crystal reversible 2+2 photo‐oligomerization of conjugated dienones under visible light is reported.
Abstract
Development of efficient and low cost electrocatalysts has been an important area of research in the field of materials chemistry. In this regard metal‐organic gels (MOGs) are one of the ...promising materials and they are being utilized for various materials applications including energy conversion and storage. Electrochemical applications of the MOGs are still in its infancy and further studies are required for exploration of structure‐property correlation that is crucial for targeted and efficient materials design. Herein we report multi stimuli responsive MOGs containing a tris‐tetrazole‐tri‐amido based organic ligand. The self‐assembly of the threefold symmetric ligand with Co(II)/Ni(II) acetates results in the MOGs with distinct morphological and structural characteristics, regardless of containing the same organic ligand. These MOGs were synthesized by direct mixing of the precursors under ambient conditions. The xerogels of these MOGs (
Co‐MOG′
and
Ni‐MOG′
) exhibit excellent OER performance as the
Co‐MOG′
and
Ni‐MOG′
shows the overpotential of 312 mV and 418 mV at 10 mA/cm
2
in an alkaline electrolyte. Electrocatalytic performance of the xerogels were correlated to their structural features like distinct morphology and porosity of the material that facilitates the mass transfer and maximum exposure to the electrochemical active sites. Importantly, this work demonstrates the functional application of MOGs as electrocatalysts for OER and the effect of metal ion, porosity and morphology on their overall performance.
An organic polymer containing cyclobutanes and amides as backbones and pyridyl groups as sidearms was synthesized by single‐crystal‐to‐single‐crystal (SCSC) 2+2‐photopolymerization in the ...coordination polymers (CPs) of diene. The diene molecule was photo‐inactive in its crystals and formed a triply intertwined 1D‐helical CP with Cd(NO3)2 and Cu(NO3)2 salts. The 1D‐CP was transformed into a coordination polymer of organic polymers containing threefold interpenetrated 3D‐networks of CdSO4 topology through a 2+2‐reaction in SCSC manner upon irradiation. The organic polymer was separated from its CPs and found to have an unusually high degree of polymerization for this type of reaction. Furthermore, the organic polymer was amenable for N‐alkylation reactions such as methylation, propylation, and decylation. The formate salts of the organic polymer and the methylated polymer were shown to form plastic films with a combination of properties such as high transparency, tensile strengths, gas permeability, thermal stability, water‐resistance, and resistance to other organic solvents. The methylated polymer was also able to capture chromate ions and anionic dyes from aqueous solutions.
Making a film: Single‐crystal‐to‐single‐crystal 2+2‐photopolymerization in coordination polymers of a diene results in an organic polymer that is amenable for functionalization. Such functionalizations result in a change of properties such as formation of plastic films, high transparency, tensile strengths, gas permeability, thermal stability, and water‐resistant nature, as well as absorption of chromate ions and anionic dyes from aqueous solutions.
The single crystals of two structural isomers of bis‐olefinic molecules were shown to have contrasting properties in terms of their photoreactivity: one exhibits an excellent ability to form ...polymers, accompanied with bending of crystals upon irradiation, while the other is photostable. The photoreactive crystal is a first example in which 2+2 polymerization leads to bending of the crystals, with implications for the design of photoactuators. The hydrate formation ability of one of these molecular isomers promotes the solid‐state reactivity in its crystal, as the H2O molecules act as a template to bring the olefin molecules into the required arrangement for 2+2 polymerization. Further, the crystals of the polymer exhibited better flexibility and smoothed surfaces compared to those of the monomers. In addition, under UV‐light the diene emits bluish violet light while the polymer emits green light, indicating that the luminescence property can be tuned through photoirradiation.
Round the bend: Single crystals of a new organic bis‐olefin are capable of bending during photoirradiation through a solid‐state 2+2 photopolymerization reaction.
Two flexible tetracarboxylic acids with ether (H4AOIA) and amine (H4ANIA) linkages have been employed for the formation of two distinct Co-metal–organic frameworks (MOFs) with diverse architectures. ...Both the MOFs were shown to demonstrate remarkable catalytic activities for the chemical conversion of CO2 into cyclic carbonates under ambient reaction conditions with considerably high turnover number values. Further, carbonization of the two-dimensional-MOF, Co-ANIA, under inert atmospheric conditions at a temperature of 800 °C resulted in the formation of cobalt containing N-doped nanocomposite (Co@NPC2). In the context of generation of a sustainable source of energy and to carry out successive conversions, the single-component nanocomposite, Co@NPC2, was shown to act as an efficient cost-effective non-noble metal electrocatalyst through its electrochemical activity toward hydrogen evolution.
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 NO3 –, ClO4 –, SO4 2–, and SiF6 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 (SiF6 2–), open (4,4)-network (NO3 – and SCN–), and the interpenetrated 2D-networks with (4,4)- and (6,3)-topologies and pseudodiamondoid network (SO4 2– and ClO4 –). 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.
Selective detection of H2S in the cellular systems using fluorescent CPs/MOFs is of great scientific interest due to their outstanding aqueous stability, biocompatibility and real‐time detection ...ability. Fabrication of such materials using complete biologically essential elements and applying them as an efficient biosensor is still quite challenging. In this context, two newly synthesized CPs containing biologically essential metal ion (Zn) and nitro/azido functional groups into the framework to sense extracellular and intracellular H2S by reducing into respective amines are presented. The CP‐1 containing the azide group acted as an efficient fluorescent turn‐on probe with the lowest detection limit (7.2 μM) and shortest response time (30 s) among the Zn‐based probes reported till date. Moreover, CP‐1 exhibited green luminescence in live cells after imaging a very low concentration of H2S, whereas the nitro analogue CP‐2 could not detect the target analyte due to its framework disruption.
Based on the reduction approach, newly synthesized coordination polymers (CPs) containing biologically essential metal ion (Zn) was shown to exhibit an excellent ability for the detection of extracellular and intracellular H2S. The CP‐1, containing azido functunal group acted as an efficient fluorencent turn‐on probe with lowest detection limit (7.2 μM) and shortest response time (30 s) among the reported Zn‐based probes to date, whereas the nitro group containing CP‐2 was unable to sense H2S due to its framework disruption.
Two bis-pyridyl-substituted ?,?-unsaturated ketones were shown to form complexes with carboxylic acids and resorcinol derivatives. The neutral acid-acid homosynthon was observed in only one complex ...out of the five acid-bis-pyridyl containing complexes studied here, while the -COO??HOOC- synthon was found to be dominant as it was observed in four complexes. The carboxylates self-assembled to form discrete dimeric, anionic, 1D chains and also exhibited mixed ionic hydrogen bonds. On the other hand, resorcinol derivatives displayed O-H?N hydrogen bonding to form tetrameric aggregates of bis-pyridyl ketone molecules and respective co-formers, while 3,5-dihydroxy benzoic acid (DHBA) molecules formed 1D chains by clipping two molecules of ketones with three DHBA molecules. Such clipping by the resorcinol derivatives promoted continuous ?-? stacking interactions. Consequently, these materials emitted at higher wavelengths compared with the parent bis-pyridyl-substituted ?,?-unsaturated ketones.
Film review: Two amide‐containing bisolefin monomers undergo solid‐state polymerization (see example) through a 2+2 reaction in a single‐crystal‐to‐single‐crystal fashion. The transformation was ...favored by the self‐templating and shock‐absorbing nature of hydrogen‐bonding layers. The pyridine‐containing polymers were soluble and useful for making plastic films with considerable tensile strengths.
