Stepwise post-modification immobilization of palladium Schiff-base complex on to the OMS-Cu (BDC) metal-organic framework for Mizoroki-Heck cross-coupling reaction

Nitrogen-enriched flexible metal-organic framework for CO2 adsorption

A novel MOF named [Zn2(L)(DMF)] was synthesized using solvothermal methods from the reaction of the new linker (4,4',4''-(4,4',4''-(benzene-1,3,5-triyltris(methylene))tris(3,5-dimethyl-1H-pyrazole-4,1-diyl))tribenzoic acid) and Zn(NO3)2·6H2O. This new MOF was characterized by means of different techniques: powder X-ray diffraction, N2 adsorption and desorption isotherms, thermogravimetric analysis, and scanning electron microscopy. Furthermore, suitable crystals were obtained, which allowed us to perform the X-Ray structure determination of this MOF. The capability of these new MOF to adsorb CO2 at different temperatures was measured and its isosteric enthalpy of adsorption was calculated. The novel MOF shows an uncommon node composed of a Zn3(-COO)6(DMF)2, and the asymmetric unit contains one crystallographically independent linker, one DMF molecule, and two Zn atoms. The [Zn2(L)(DMF)] MOF is a microporous material with high crystallinity and stability up to 250 °C. The multiple nitrogenated pyrazole linkers in its framework enhance its CO2 adsorption capabilities. This material exhibits a low CO2 isosteric enthalpy of adsorption (Hads), comparable to previously reported values for similar nitrogenated materials. All the observed CO2 adsorption capacities were further supported by DFT calculations.

Schiff base MOFs and their derivatives for sequestration and degradation of pollutants: present and future

Removal of contaminants via adsorption and catalysis have received a significant interest as energy and money-saving solutions for treating the world's wastewater. Metal-organic frameworks (MOFs), a newly discovered class of porous crystalline materials, have demonstrated tremendous promise in the removal and destruction of contaminants for water purification. In order to improve the interactions of MOFs with the target pollutants for their selective removal and degradation, the Schiff base functionalities emerged as promising active sites. Through pre- and post-synthetic alterations, Schiff base functionalities are integrated into the pore cages of MOF adsorbent materials. To understand the adsorptive/catalytic mechanism, potential interactions between the Schiff base sites and the target pollutants are discussed. Based on cutting-edge techniques for their synthesis, this paper examines current developments in the creation of Schiff base-functionalized MOFs as innovative materials for adsorptive removal and catalytic degradation of contaminants for water remediation.

Efficient and biocompatible new palladium-supported boehmite nanoparticles: synthesis, characterization and application in Suzuki-Miura and Mizoroki-Heck coupling reactions

Palladium complex-supported on boehmite (Pd(0)-SMTU-boehmite) nanoparticles were synthesized and characterized by using XRD, SEM, EDS, TGA, BET, ICP and FT-IR techniques. When applied as a new catalyst for C-C coupling reactions of Suzuki-Miyaura and Mizoroki-Heck in PEG-400 solvent, the Pd(0)-SMTU-boehmite nanoparticles showed excellent activity and recyclability. The study of palladium leaching by the ICP-OES technique and hot filtration led to the catalyst exhibiting excellent stability and recyclability.

Stabilization of Pd NPs over the surface of β-cyclodextrin incorporated UiO-66-NH2 for the C-C coupling reaction

Here, we prepared UiO-66-NH₂ and employed a post-synthesis modification method for its functionalization with a β-cyclodextrin (β-CD) organic compound. The resulting composite was employed as a support for the heterogenization of the Pd NPs. Various techniques, including FT-IR, XRD, SEM, TEM, EDS, and elemental mapping, were used to characterize UiO-66-NH₂@β-CD/Pd_NPs, indicating its successful preparation. Three C-C coupling reactions, including the Suzuki, Heck, and Sonogashira coupling reactions, were promoted using the produced catalyst. As a result of the PSM, the proposed catalyst displays improved catalytic performance. In addition, the suggested catalyst was highly recyclable up to 6 times.

Magnetically and Electrically Responsive Soft Actuator Derived from Ferromagnetic Bimetallic Organic Framework

The advancement in smart devices and soft robotics necessitates the use of multiresponsive soft actuators with high actuation stroke and stable reversibility for their use in real-world applications. Here, this work reports a magnetically and electrically dual responsive soft actuator based on neodymium and iron bimetallic organic frameworks (NdFeMOFs@700). The ferromagnetic NdFeMOFs@700 exhibits a porous carbon structure with excellent magnetization saturation (166.96 emu g^-1 ) which allows its application to a dual functional material in both magnetoactive and electro-ionic actuations. The electro-ionic soft actuator, which is fabricated using NdFeMOFs@700 and PEDOT-PSS, demonstrates 4.5 times higher ionic charge storage capacity (68.21 mF cm^-2 ) and has excellent cycle stability compared with the PEDOT-PSS based actuator. Under a low sinusoidal input voltage of 1 V, the dual-responsive actuator displays bending displacement of 15.46 mm and also generates deflection of 10 mm at 50 mT. Present results show that the ferromagnetic bimetallic organic frameworks can open a new way to make dual responsive soft actuators due to the hierarchically porous structures with its high redox activity, superior magnetic properties, and larger electrochemical capacitance. With the NdFeMOFs@700 based soft actuators, walking movement of a starfish robot is demonstrated by applying both the magnetic and electric fields.

Palladium Nanoparticle-Decorated Porous Metal-Organic-Framework (Zr)@Guanidine: Novel Efficient Catalyst in Cross-Coupling (Suzuki, Heck, and Sonogashira) Reactions and Carbonylative Sonogashira under Mild Conditions

A novel heterogeneous Zr-based metal-organic framework containing an amino group functionalized with nitrogen-rich organic ligand (guanidine), through a step-by-step post synthesis modification approach, was successfully modified by the stabilization of palladium metal nanoparticles on the prepared UiO-66-NH₂ support in order to synthesize the Suzuki-Murray, Mizoroki-Heck, and copper-free Sonogashira reactions and also the carbonylative Sonogashira reaction incorporating H₂O as a green solvent under mild conditions. This newly synthesized highly efficient and reusable UiO-66-NH₂@cyanuric chloride@guanidine/Pd-NPs reported catalyst has been utilized to increase anchoring palladium onto the substrate with the aim of altering the construction of the intended synthesis catalyst to form the C-C coupling derivatives. Several strategies, including X-ray diffraction, Fourier transform infrared, scanning electron microscopy, Brunauer-Emmett-Teller, transmission microscopy electron, thermogravimetric analysis, inductively coupled plasma, energy-dispersive X-ray, and elemental mapping analyzes, were used to indicate the successful preparation of the UiO-66-NH₂@cyanuric chloride@guanidine/Pd-NPs. In these reactions, the UiO-66-NH₂-supported Pd-NPs illustrated superior performances compared to their catalyst, revealing the benefits of providing nanocatalysts. As a result, the proposed catalyst is favorable in a green solvent, and also, the outputs are accomplished with good to excellent outputs. Furthermore, the suggested catalyst represented very good reusability with no remarkable loss in activity up nine sequential runs.

Stabilization of Palladium-Nanoparticle-Decorated Postsynthesis-Modified Zr-UiO-66 MOF as a Reusable Heterogeneous Catalyst in C-C Coupling Reaction

Here we prepared a highly efficient and reusable catalyst by a step-by-step postsynthesis modification of UiO-66-NH2 metal-organic frameworks (MOFs) with nitrogen-rich organic ligands and used it as support for the preparation of UiO-66-NH2@cyanuric chloride@2-aminopyrimidine/PdNPs. The catalytic performance's results of UiO-66-NH2@cyanuric chloride@2-aminopyrimidine/PdNPs, UiO-66-NH2/PdNPs, and UiO-66-NH2@cyanuric chloride/PdNPs indicate high efficiency of the modulation of the microenvironment of the palladium NPs. The addition of N-rich organic ligands through postsynthesis modification caused a unique structure of the final composite in favor of the progress of the C-C coupling reaction. Various techniques, including FT-IR, XRD, SEM, TEM, EDS, and elemental mapping, were used to characterize UiO-66-NH2@cyanuric chloride@2-aminopyrimidine/PdNPs, indicating its successful preparation. Three C-C coupling reactions, including the Suzuki, Heck, and Sonogashira coupling reactions, were promoted using the produced catalyst. As a result of the postsynthesis modification (PSM), the proposed catalyst displays improved catalytic performance. In addition, the suggested catalyst was highly recyclable up to ten times without leaching of PdNPs.

A novel strategy for stabilization of sub-nanometric Pd colloids on kryptofix functionalized MCM-41: nanoengineered material for Stille coupling transformation

The stabilization of sub-nanometric metal particles (< 1 nm) with suitable distribution remained challenging in the catalytic arena. Herein, an intelligent strategy was described to anchoring and stabilizing sub-nanometric Pd colloids with an average size of 0.88 nm onto Kryptofix 23 functionalized MCM-41. Then, the catalytic activity of Pd@Kryf/MCM-41 was developed in Stille coupling reaction with a turnover frequency (TOF) value of 247 h-1. The findings demonstrate that porous MCM-41 structure and high-affinity Kryptofix 23 ligand toward adsorption of Pd colloids has a vital role in stabilizing the sub-nanometric particles and subsequent catalytic activity. Overall, these results suggest that Pd@Kryf/MCM-41 is a greener, more suitable option for large-scale applications and provides new insights into the stabilization of sub-nanometric metal particles.

A comprehensive survey upon diverse and prolific applications of chitosan-based catalytic systems in one-pot multi-component synthesis of heterocyclic rings

Heterocyclic compounds are among the most prestigious and valuable chemical molecules with diverse and magnificent applications in various sciences. Due to the remarkable and numerous properties of the heterocyclic frameworks, the development of efficient and convenient synthetic methods for the preparation of such outstanding compounds is of great importance. Undoubtedly, catalysis has a conspicuous role in modern chemical synthesis and green chemistry. Therefore, when designing a chemical reaction, choosing and or preparing powerful and environmentally benign simple catalysts or complicated catalytic systems for an acceleration of the chemical reaction is a pivotal part of work for synthetic chemists. Chitosan, as a biocompatible and biodegradable pseudo-natural polysaccharide is one of the excellent choices for the preparation of suitable catalytic systems due to its unique properties. In this review paper, every effort has been made to cover all research articles in the field of one-pot synthesis of heterocyclic frameworks in the presence of chitosan-based catalytic systems, which were published roughly by the first quarter of 2020. It is hoped that this review paper can be a little help to synthetic scientists, methodologists, and catalyst designers, both on the laboratory and industrial scales.

Application of novel nanomagnetic metal-organic frameworks as a catalyst for the synthesis of new pyridines and 1,4-dihydropyridines via a cooperative vinylogous anomeric based oxidation

Herein, a new magnetic metal-organic frameworks based on Fe3O4 (NMMOFs) with porous and high surface area materials were synthesized. Then, NMMOFs were characterized by FT-IR, XRD, SEM, elemental mapping, energy dispersive X-ray (EDS), TG, DTG, VSM, and N2 adsorption-desorption isotherms (BET). Fe3O4@Co(BDC)-NH2 as a magnetic porous catalyst was applied for synthesis of novel fused pyridines and 1,4-dihydropyridines with pyrazole and pyrimidine moieties as suitable drug candidates under ultrasonic irradiation. The significant advantages of the presented methodology are mild, facile workup, high yields, short reaction times, high thermal stability, and reusability of the described NMMOFs catalyst.

Fe-MIL-101 modified by isatin-Schiff-base-Co: a heterogeneous catalyst for C–C, C–O, C–N, and C–P cross coupling reactions

Fe-MIL-101-isatin-Schiff-base-Co was synthesized and applied as a catalyst for Ullmann-type, Buchwald–Hartwig, Hirao, Hiyama and Mizoroki–Heck cross-coupling reactions of aryl halides.

Amine-functionalized metal–organic framework-based Pd nanoparticles: highly efficient multifunctional catalysts for base-free aerobic oxidation of different alcohols

Metal–organic framework-based palladium nanoparticles are found to be highly efficient multifunctional catalysts for the base-free aerobic oxidation of different aliphatic, aromatic and hetero-aromatic alcohols.

Mesoporous Palladium N,N'-Bis(3-Allylsalicylidene)o-Phenylenediamine-Methyl Acrylate Resins as Heterogeneous Catalysts for the Heck Coupling Reaction

Palladium N,N'-bis(3-allylsalicylidene)o-phenylenediamine complex (PdAS) immobilized onto mesoporous polymeric methyl acrylate (MA) based resins (PdAS(x)-MA, x = 1, 2, 5, or 10 wt.%) were successfully prepared as heterogeneous catalysts for the Heck reaction. The catalysts were synthesized via radical suspension polymerization using PdAS as a metal chelate monomer, divinylbenzene and MA as co-monomers. The effect of the PdAS(x) content on the physicochemical properties of the resins is also reported. The catalysts were characterized by using a range of analytical techniques. The large surface area (>580 m²·g^-1) and thermal stability (up to 250 °C) of the PdAS(x)-MA materials allows their application as catalysts in the C-C coupling reaction between iodobenzene and MA in the presence of trimethylamine at 120 °C using DMF as the solvent. The PdAS(10)-MA catalyst exhibited the highest catalytic performance with no significant catalytic loss being observed after five reuses, thereby indicating excellent catalyst stability in the reaction medium.