Novel catalytic materials are highly demanded to perform a variety of catalytic organic reactions. MOFs combine the benefits of heterogeneous catalysis like easy post reaction separation, catalyst ...reusability, high stability and homogeneous catalysis such as high efficiency, selectivity, controllability and mild reaction conditions. The possible organization of active centers like metallic nodes, organic linkers, and their chemical synthetic functionalization on the nanoscale shows potential to build up MOFs particularly modified for catalytic challenges. In this review, we have summarized the recent research progress in heterogeneous catalysis by MOFs and their catalytic behavior in various organic reactions, highlighting the key features of MOFs as catalysts based on the active sites in the framework. Examples of their post functionalization, inclusion of active guest species and metal nanoparticles have been discussed. Finally, the use of MOFs as catalysts for asymmetric heterogeneous catalysis and stability of MOFs has been presented as separate sections.
Novel catalytic materials are highly demanded to perform a variety of catalytic organic reactions.
New well-designed materials are highly demanded with the prospect of versatile properties, offering successful applications as alternates to conventional materials. Major new insights into ...metal-organic self-assembled structures assisting biochemical purposes have recently emerged. Metal-organic polyhedral cages are highlighted as new research materials to be used for therapeutic, sensing and imaging, purposes
etc
. This tutorial review covers achievements in the biochemical applications of these multinuclear complexes. Examples of their ability to aid the ionic transport, biomolecular sensing, imaging, and drug delivery are presented.
New well-designed materials are highly demanded with the prospect of versatile properties, offering successful applications as alternates to conventional materials.
•Self-assembled metal-carboxylates of angular/linear di- and tritopic linkers are discussed.•Mixed ligands, interconversion, and postmodifications of nanopolyhedra are addressed.•Crucial synthetic ...protocols for metal to ligand self-organization are summarized.•Potential applications via molecular guest encapsulation mechanism are reported.•These nanocages serve as substrates for extended networks, in sorption, catalytic, and biomedical processes.
Discrete metal-carboxylate cage-like materials are an important class of metal-organic polyhedra. The designs of these self-assemblies in terms of their characteristic polygonal shape, surface area, and related properties are functions of metal centers and carboxylate bridging linkers. Thus, several combinations of different metal ions with angular, linear ditopic, or tritopic carboxylic links can be integrated to map these nanoscale materials, as well as the optional functional groups for the ligands. Synthetic protocols based on variations in the solvent, temperature, and pressure can be employed to achieve metal-carboxylate self-organization. These types of discrete polyhedral nanocages with an internal void are materials with a broad spectrum of potential future uses as substrates for extended networks and highly selective gas sorbents in catalysis and biomedical processes.
Synthesis of 2D MOFs is often sensitive to the reaction conditions like temperature and solvent
etc.
Cu(
ii
)-5-azidoisophthalate MOF (Cu(
ii
)–5N
3
IP) has been synthesized at room temperature as ...well as under solvothermal conditions. The azide functional group remained stable during solvothermal synthesis at 85 °C. Cu(
ii
)–5N
3
IP crystallized in a Kagomé-type structure. Typical Cu
2
paddle-wheels are connected to each other by 5N
3
IP ligands in infinite 2D sheets in the (001) plane, featuring 1D infinite channels within each layer. This MOF is used for the adsorption of methylene blue (MB), rhodamine B (RhB), methyl orange (MO), and Congo red (CR). The adsorption is selective to the dimensions, shapes and ionic strengths of the dyes. Cu(
ii
)–5N
3
IP exhibited adsorption rates in the order MB > CR > RhB > MO. Cu(
ii
)–5N
3
IP is used as a catalyst for aerobic oxidation and Knoevenagel condensation. 3–10 mol% of Cu–5N
3
IP selectively catalyzes the oxidation of benzyl alcohol to benzaldehyde in 9–20 h at 60 °C. In Knoevenagel condensation, the reaction of both unsubstituted and substituted benzaldehydes at room temperature was observed at a very low catalyst loading of 3 mol% of MOF within a short time of 3–60 min. This 2D MOF has proved to be more efficient for dye adsorption and the catalytic applications under investigation (such as alcohol oxidation and Knoevenagel condensation) than its analogous 3D or 0D materials.
The coordination networking of discrete metal-organic polyhedra (MOPs) involving different ligands as well as metals is a challenging task due to the features of limited solubility and chemical ...stability of these polyhedra. An unusual approach, ligand-oriented polyhedral networking via click chemistry and further metal coordination is reported here. An alkyne decorated Cu(II)-MOP self-catalyzes the regioselective click reaction (1,3-dipolar cycloaddition) using azide-functionalized ligands under unconventional reaction conditions. Introducing new metal ions, M(II), interlinks the carboxylic groups on the MOP surfaces creating coordination networks. On the other hand, exposure of the respective individual ligand components in the presence of Cu(II) promotes an in-situ click reaction along with metal coordination generating a new 3D-framework. These materials demonstrated a high drug hosting potential exhibiting a controlled progressive release of anticancer (5-flourouracil) and stimulant (caffeine) drugs in physiological saline at 37 °C. These innovative and unconventional MOP networks provide a significant conceptual advance in understanding.
Water splitting is the key step towards artificial photosystems for solar energy conversion and storage in the form of chemical bonding. The oxidation of water is the bottle‐neck of this process that ...hampers its practical utility; hence, efficient, robust, and easy to make catalytic systems based on cheap and earth‐abundant materials are of exceptional importance. Herein, an in situ generated cobalt catalyst, CoII(TCA)2(H2O)2 (TCA=1‐mesityl‐1,2,3‐1H‐triazole‐4‐carboxylate), that efficiently conducts photochemical water oxidation under near‐neutral conditions is presented. The catalyst showed high stability under photolytic conditions for more than 3 h of photoirradiation. During electrochemical water oxidation, the catalytic system assembled a catalyst film, which proved not to be cobalt oxide/hydroxide as normally expected, but instead, and for the first time, generated a molecular cobalt complex that incorporated the organic ligand bound to cobalt ions. The catalyst film exhibited a low overpotential for electrocatalytic water oxidation (360 mV) and high oxygen evolution peak current densities of 9 and 2.7 mA cm−2 on glassy carbon and indium‐doped tin oxide electrodes, respectively, at only 1.49 and 1.39 V (versus a normal hydrogen electrode), respectively, under neutral conditions. This finding, exemplified on the in situ generated cobalt complex, might be applicable to other molecular systems and suggests that the formation of a catalytic film in electrochemical water oxidation experiments is not always an indication of catalyst decomposition and the formation of nanoparticles.
Finding active catalytic species: An in situ generated cobalt catalyst efficiently conducts photo‐ and electrochemical water oxidation under near‐neutral conditions. This work sheds light upon the ability to directly assemble molecular metal–organic catalyst films on the surface of different conducting electrodes for the potential molecular engineering of cobalt‐based electrocatalytic films.
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•Novel mono- and dinuclear dimethyltin(IV) complexes were synthesized and fully characterized.•They are highly active catalyst for the synthesis of cyclic carbonate from epoxides and ...CO2 at ambient pressure.•The reaction proceeds with high conversion up to 100% and TONs of 1000, which is the best among tin-based compounds.•The catalyst is continuously used three times without any loss in catalytic activity.
Novel mono- and dinuclear dimethyltin(IV) complexes were synthesized using tridentate Schiff base ligands, derived from 2-amino-2-hydroxymethyl-propane-1,3-diol and various aldehydes. These diorganotin(IV) compounds displayed good catalytic activity for solvent-free cycloaddition of CO2 to epoxides at ambient pressure. These catalysts efficiently completed the insertion of CO2 to various epoxides at low catalyst loadings (0.1–1.0 mol%) in 1–6 hours giving high values of TONs around 1000. The catalyst further usability for three continuous reaction runs in the reaction mixture gives the same activity revealing the remarkable stability of these compounds under the given reaction conditions. Therefore, organotin(IV) complexes are efficient catalysts for the synthesis of the industrially important cyclic carbonates from epoxides at ambient pressure under solvent-free conditions.
A series of novel
N
′-arylmethylidene-3-methyl-1-phenyl-6-
p
-chlorophenyl-1
H
-pyrazolo3,4-
b
pyridine-4-carbohydrazide (
2a
–
2t
) has been synthesized from hydrazide (
1
). The structures of newly ...synthesized compounds were confirmed by FT-IR, EI-MS,
1
H NMR and
13
C NMR techniques. The title compounds were evaluated for antioxidant and antiplatelet aggregation effect induced by arachidonic acid (AA) and collagen. All the compounds have exhibited high antioxidant potential and antiplatelet activity but (
2c
,
2e
,
2f
,
2g
,
2i
,
2m
,
2o
and
2q
) have revealed superlative antiplatelet activity. The molecular docking against cyclooxygenase-1 and 2 (COX-1 and COX-2) and quantitative structure-activity relationship (QSAR) were performed in describing their antiplatelet potential against AA and collagen along with antioxidant potential determined by ABTS, DPPH and iron chelating methods. The molecular docking study exhibited that compounds (
2c
,
2e
,
2f
,
2g
,
2i
,
2l
,
2m
,
2o
and
2q
) were found to be active against COX-1 while
2o
compound also showed activity against COX-2. Compounds
2g
and
2l
were found to have higher energy stabilization values in comparison to Aspirin. Computational evaluations both molecular docking and QSAR are in good agreement with antiplatelet and antioxidant activities of the compounds (
2a
–
2t
). All the compounds especially
2g
,
2l
,
2m
might be promising antiplatelet agents and might be helpful in the synthesis of new drugs for the treatment of cardiovascular and anti-inflammatory diseases.
Graphical Abstract
•Novel thiosemicarbazones synthesized from carbonyl compounds and thiosemicarbazide.•Compounds characterized using UV-Vis and FT-IR spectral techniques.•Demonstrated potent antibacterial activity ...against Bacillus subtilis and Escherichia coli.•Exhibited significant antidiabetic activity, surpassing acarbose in molecular docking.•Promising candidates WS-1 and WS-2 showed lowest binding energies with Alpha-glucosidase.
Thiosemicarbazones and their derivatives were synthesized by reacting carbonyl compounds with thiosemicarbazide, followed by treatment with metal salts. The prepared thisemicarbazones such as (2E)-2-(1,5,7-trichloronaphthalen-2-yl)-methylidene-hydrazine-1-carbothioamide,(2E)-2-(1,5,7-trihydroxynaphthalen-2-yl)-methylidenehydrazine-1-carbothioamide and these were characterized by using diverse spectral techniques, such as UV–Vis and FT-IR. The synthesized compounds were subsequently evaluated for their antibacterial properties against Gram(+) Bacillus subtilis and Gram(-) Escherichia coli, using ciprofloxacin as a reference, as well as for their anti-microbial activities. For the evaluation of anti-diabetic activity, Acarbose served as the reference. Molecular docking results indicated that WS-1 and WS-2 exhibited superior performance against Alpha-glucosidase proteins, evidenced by their lowest binding energies (−8.1 and −8.3 kcal/mol) respectively compared to other ligands. These findings suggest that WS-1 and WS-2 are promising candidates for further research and development by pharmaceutical companies to explore additional biological activities.
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Water splitting is the key step towards artificial photosystems for solar energy conversion and storage in the form of chemical bonding. The oxidation of water is the bottle-neck of this process that ...hampers its practical utility; hence, efficient, robust, and easy to make catalytic systems based on cheap and earth-abundant materials are of exceptional importance. Herein, an in situ generated cobalt catalyst, Co-II(TCA)(2)(H2O)(2) (TCA=1-mesityl-1,2,3-1H-triazole-4-carboxylate), that efficiently conducts photochemical water oxidation under near-neutral conditions is presented. The catalyst showed high stability under photolytic conditions for more than 3 h of photoirradiation. During electrochemical water oxidation, the catalytic system assembled a catalyst film, which proved not to be cobalt oxide/hydroxide as normally expected, but instead, and for the first time, generated a molecular cobalt complex that incorporated the organic ligand bound to cobalt ions. The catalyst film exhibited a low overpotential for electrocatalytic water oxidation (360 mV) and high oxygen evolution peak current densities of 9 and 2.7 mA cm(-2) on glassy carbon and indium-doped tin oxide electrodes, respectively, at only 1.49 and 1.39 V ( versus a normal hydrogen electrode), respectively, under neutral conditions. This finding, exemplified on the in situ generated cobalt complex, might be applicable to other molecular systems and suggests that the formation of a catalytic film in electrochemical water oxidation experiments is not always an indication of catalyst decomposition and the formation of nanoparticles.
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