A Ni-MOF as Fluorescent/Electrochemical Dual Probe for Ultrasensitive Detection of Picric Acid from Aqueous Media.

A water-stable, microporous, luminescent Ni(II)-based metal-organic framework (MOF) (Ni-OBA-Bpy-18) with a 4-c uninodal sql topology was solvothermally synthesized using mixed N-, O-donor-directed π-conjugated co-ligands. The extraordinary performance of this MOF toward rapid monitoring of mutagenic explosive trinitrophenol (TNP) in aqueous and vapor phases by the fluorescence "Turn-off" technique with an ultralow detection limit of 66.43 ppb (Ksv: 3.45 × 105 M-1) was governed by a synchronous occurrence of photoinduced electron transfer-resonance energy transfer-intermolecular charge transfer (PET-RET-ICT) and non-covalent π···π weak interactions, as revealed from density functional theory studies. The recyclable nature of the MOF, detection from complex environmental matrices, and fabrication of a handy MOF@cotton-swab detection kit certainly escalated the on-field viability of the probe. Interestingly, the presence of electron-withdrawing TNP decisively facilitated the redox events of the reversible NiIII/II and NiIV/III couples under an applied voltage based on which electrochemical recognition of TNP was realized by the Ni-OBA-Bpy-18 MOF/glassy carbon electrode, with an excellent detection limit of ∼0.6 ppm. Such detection of a specific analyte by MOF-based probe via two divergent yet coherent techniques is unprecedented and yet to be explored in relevant literature.

Porous organic-inorganic hybrid materials for catalysis, energy and environmental applications.

The introduction of organic functionalities into porous inorganic materials not only makes the resulting hybrid porous framework to be more flexible and hydrophobic, but also provides additional scope for anchoring metal binding sites, which is beneficial for different frontline applications. Furthermore, the nanoscale porosity and high surface area of these organic-inorganic hybrid materials offer a better dispersion of active sites, which greatly enhances their application potential in adsorption, sensing, drug-delivery, energy storage, optoelectronics, light harvesting and catalysis. Easy post-synthetic functionalization of these hybrid materials has widened their application potential. Herein, we highlight several important synthetic strategies to design a wide range of organic-inorganic hybrid porous materials starting from the respective molecular precursors and their task-specific applications in energy and environmental research. We also outline the recent developments in their respective application areas together with various challenges that need to be overcome.

Metal-Thiolate Framework for Electrochemical and Photoelectrochemical Hydrogen Generation.

Hydrogen has evolved as the cleanest and most sustainable fuel, produced directly from naturally abundant water resources. Generation of hydrogen by electrochemical or photoelectrochemical splitting of water has been conceived as the most effective method for hydrogen production. Herein, a robust solid metal-thiolate framework (MTF-1) was obtained by hydrothermal crystallization of the reaction mixture consisting of 1,3,5-triazine-2,4,6-trithioltrisodium salt and CuII under mild synthesis conditions. The material was thoroughly characterized and explored as efficient catalyst for electrochemical and photoelectrochemical hydrogen evolution reaction (HER) via water splitting reactions. MTF-1 showed onset potential 0.045 VRHE and overpotential η(@10 mA cm-2 ) at 0.096 VRHE . The electrochemical surface area of MTF-1 was found to be 509 m2 g-1 . The photo current density at pH 5.0 was found to be 0.487 mA cm-2 at 0.6 VRHE . The feasibility of the reaction pathway was correlated from the density function theory study, which suggested the complete downhill energetics indicating spontaneous electrochemical hydrogen generation in the acidic medium.

Nickel Nanoparticles Immobilized over Mesoporous SBA-15 for Efficient Carbonylative Coupling Reactions Utilizing CO2: A Spotlight.

Ecofriendly routes for the synthesis of carbamates and carbonylative coupling products such as benzyl formate derivatives are very demanding for both academia and industries. Foreseeing a sustainable green future, we systematically analyzed the synthesis history of both these chemicals, mentioning their pros and cons. As a step towards green chemistry, here we have optimized the reaction conditions for the synthesis of various benzyl formates from corresponding benzyl halides and carbamates from substituted anilines and alkyl halides catalyzed by Ni(0) nanoparticles (NPs) immobilized over amine-functionalized ordered mesoporous SBA-15 material in the presence of CO2 as C1 source. This spotlight on applications is aimed to provide a clear outlook to date regarding the gradual progress in the synthesis of both these aforementioned chemicals and finally addresses further efforts for overcoming the current challenges.

Transformation of Wurtzite ZnO to a New Triclinic Nanoporous ZnO Phase via Hydrothermal Treatment with Metformin for Designing Proton Conducting Material.

Zinc oxide is one of the most widely studied semiconductor metal oxides, which predominantly crystallizes as hexagonal wurtzite and often cubic zinc-blende phases. Here we report the transformation of the highly stable wurtzite ZnO to a new triclinic phase NZO-2 by using metformin as a template during post-synthesis hydrothermal treatment. This crystalline phase of the material NZO-2 has been identified through the refinement of the powder XRD data. NZO-2 possesses porous rod like particle morphology consisting of the self-assembly of 3-7 nm size spherical nanoparticles and interparticle nanoscopic voids spaces. NZO-2 has been surface phosphorylated and the resulting material displayed good proton conductivity. Further, NZO-2 displayed ultra-low band gap of 1.74 eV, thereby responsible for red emission under high energy laser excitation and this may open new opportunities in optoelectronic application of ZnO.