Zinc metal-organic frameworks: efficient catalysts for the diastereoselective Henry reaction and transesterification

Stimuli-responsive Zn(ii) complexes showing the structural conversion and on/off switching of catalytic properties

In this work, we report a series of dinuclear Zn(ii) complexes and their corresponding catalytic properties for a transesterification reaction. We show that the structures and catalytic activity of the complexes are strongly dependent on their molecular structures surrounding the metal centres. The use of halides yields a series of [Zn2X4L] (X = Cl, Br, and I) complexes with low catalytic activity because of the fully saturated coordination environment, whereas Zn(ClO4)2 results in two isomeric [ZnL] n 1D coordination polymers with efficient catalytic properties, despite being susceptible to structural rearrangement and consequent changes in catalytic activity over time. The response to chemical stimuli to trigger anion exchange allows for switching on/off the systems' catalytic activity, simultaneously recovering the catalytic effect upon degradation and thus reconstructing the coordination environment of the 1D polymer.

Efficacy of a Zn-based metalorganic framework doped with benznidazole on acute experimental Trypanosoma cruzi infection

Metal-Organic Frameworks (MOFs) have been shown to enhance the activity of encapsulated compounds by facilitating their passage across cell membranes, thereby enabling controlled and selective release. This study investigates the efficacy of BNZ@Zn-MOFs against the acute phase of Trypanosoma cruzi infection in a mouse model. The particles were synthesized by electroelution (EL), doped with BZN via mechanochemistry, and characterized using scanning electron microscopy (SEM), infrared spectroscopy (FTIR), and X-ray diffraction (XRD). BNZ@Zn-MOFs released 80% of the encapsulated BZN within 3 h, demonstrating no cytotoxicity in NIH-3T3 and HeLa cells. Furthermore, in a model of acute experimental T. cruzi-infection in BALB/c mice, the delivery system exhibited antiparasitic activity at a significantly lower BZN concentration compared to free BZN treatment. PCR analysis of treated mice revealed no parasite DNA in their tissues, and hematoxylin-eosin staining showed no apparent damage to tissue architecture. Additionally, serum levels of liver function enzymes remained unchanged, indicating no adverse effects on liver function. This delivery system, utilizing suboptimal BZN doses, enables the preservation of drug activity while potentially facilitating a substantial decrease in side effects associated with Chagas disease treatment.

From Operando Raman Mechanochemistry to "NMR Crystallography": Understanding the Structures and Interconversion of Zn-Terephthalate Networks Using Selective 17O-Labeling

The description of the formation, structure, and reactivity of coordination networks and metal-organic frameworks (MOFs) remains a real challenge in a number of cases. This is notably true for compounds composed of Zn2+ ions and terephthalate ligands (benzene-1,4-dicarboxylate, BDC) because of the difficulties in isolating them as pure phases and/or because of the presence of structural defects. Here, using mechanochemistry in combination with operando Raman spectroscopy, the observation of the formation of various zinc terephthalate compounds was rendered possible, allowing the distinction and isolation of three intermediates during the ball-milling synthesis of Zn3(OH)4(BDC). An "NMR crystallography" approach was then used, combining solid-state NMR (1H, 13C, and 17O) and density functional theory (DFT) calculations to refine the poorly described crystallographic structures of these phases. Particularly noteworthy are the high-resolution 17O NMR analyses, which were made possible in a highly efficient and cost-effective way, thanks to the selective 17O-enrichment of either hydroxyl or terephthalate groups by ball-milling. This allowed the presence of defect sites to be identified for the first time in one of the phases, and the nature of the H-bonding network of the hydroxyls to be established in another. Lastly, the possibility of using deuterated precursors (e.g., D2O and d 4-BDC) during ball-milling is also introduced as a means for observing specific transformations during operando Raman spectroscopy studies, which would not have been possible with hydrogenated equivalents. Overall, the synthetic and spectroscopic approaches developed herein are expected to push forward the understanding of the structure and reactivity of other complex coordination networks and MOFs.

Polyaromatic Carboxylate Ligands Based Zn(II) Coordination Polymers for Ultrasound-Assisted One-Pot Tandem Deacetalization–Knoevenagel Reactions

Solvothermal reactions between the polyaromatic group containing carboxylic acid pro-ligands 5-{(pyren-1-ylmethyl)amino}isophthalic acid (H2L1) and 5-{(anthracen-9-ylmethyl)amino}isophthalic acid (H2L2) with Zn(NO3)2·6H2O led to the formation of the new 1D coordination polymer [Zn(L1)(NMF)]n (1) and four other coordination polymers, [Zn(L1)(DMF)]n (2), [Zn(L1)(4,4′-Bipy)]n (3), [Zn(L2)(DMF)(H2O)2]n·n(H2O) (4) and [Zn2(L2)2(DMF)(CH3OH)]n (5), which were previously reported by our group. Single crystal X-ray diffraction analyses revealed that the CP 1 has a one-dimensional (1D) double-chain-type structure similar to that of CP 2. For CP 3, the assembly of the Zn(II) ion with a deprotonated L12− ligand and 4,4′-bipyridine produces a 3D network. CP 4 and 5 exhibit 1D linear and 2D layered-type structures. The ultrasound-assisted tandem reactions promoted by CPs have not yet been well studied. Thus, in the present work, we have investigated the catalytic activities of the newly synthesized CP 1, as well as of the other CPs 2–5, towards the tandem deacetalization–Knoevenagel condensation reactions of various acetals under ultrasonic irradiation. They proved to be highly efficient, with special emphasis on catalyst 1, which completely converted the substrate (benzaldehyde dimethyl acetal) into the desired product (2-benzylidenemalononitrile) after 2 h. The stability of the catalysts, namely regarding the action of ultrasonic radiation, was demonstrated by their reuse, where only a slight loss of activity was observed after four cycles. Heterogeneity was also demonstrated, and no leaching was detected over the various cycles.

Designing and Construction of Polyaromatic Group Containing Cd(II)-based Coordination Polymers for Solvent-free Strecker-type Cyanation of Acetals

In the present work, we have synthesized and characterized two novel Cd(II) coordination polymers, [Cd4(L1)4(DMF)6]n.3n(DMF) (1) and [Cd2(L2)2(DMF)3]n.2n(DMF) (2), and studied their catalytic application. They were synthesized via solvothermal reaction...

HKUST-1 Metal Organic Framework as an Efficient Dual-Function Catalyst: Aziridination and One-Pot Ring-Opening Transformation for Formation of β-Aryl Sulfonamides with C-C, C-N, C-S, and C-O Bonds

Metal-organic frameworks (MOFs) are extensively used in catalysis due to their robust structure, well-defined periodic reaction centers, and high porosity. We report Cu₃(BTC)₂·(H₂O)₃ (HKUST-1) as an efficient heterogeneous catalyst for aziridination of alkene and ring-opening reaction of activated aziridines. Furthermore, we demonstrate that the transfer of a nitrogen group from PhINTs to olefins and its analogue to give aziridines takes place at the coordinatively unsaturated Cu(II) site of Cu₃(BTC)₂-MOF; however, the ring opening of activated aziridines is controlled by the Cu(II) Lewis acid site, and generation of coordinative unsaturation by thermal activation of the MOF is not necessarily important. The key advantage of this catalytic approach is the direct formation of C-C, C-N, C-O, and C-S bonds yielding β-aryl sulfonamide derivatives through a simultaneous aziridination ring-opening reaction of the alkene in one pot using a single catalyst.

High performance of ultrasonic-assisted synthesis of two spherical polymers for enantioselective catalysis

Chiral polymers have aroused great attention in among chiral supramolecular materials based on their features. Herein, for the first time, the synthesis of chiral polymeric composites (CMNPs/1,4-Zbtb & 1,3-Zbtb) have been reported with entrapment through three strategies: ultrasonic irradiation, solvothermal, and mechanical stirring. According to the obtained results, it is found that ultrasound-assisted synthesis can be considered as an inexpensive and efficient method than the others, from the point ofviewof energy and time consuming. In this strategy, encapsulation of chiral magnetic nanoparticles (CMNPs) by using tetrazole-based polymers (Zbtbs) happens, in-situly. These chiral sphere-like inorganic-organic polymers can be considered as core and shell composites with catalytic activity due to their acidic (semi unsaturated Zn: open metal sites) and basic (abundant basic nitrogens) centers. In these structures, the unprecedented chirality induction can happen from the core to shell by non-covalent interaction, easily. They could catalyze symmetric oxidation and asymmetric henry condensation to give chiral β-nitroalkanol. Circular dichroism and chiral gas chromatography were used to characterize the produced enantiomers. These chiral polymeric materials can be considered as unique acid-base bifunctional catalysts with efficient properties such as high stability, enantiomeric excess, enantioselectivity to the main product, and protecting from CMNPs leaching.

Metal-Organic Frameworks as Versatile Heterogeneous Solid Catalysts for Henry Reactions

Metal–organic frameworks (MOFs) have become one of the versatile solid materials used for a wide range of applications, such as gas storage, gas separation, proton conductivity, sensors and catalysis. Among these fields, one of the more well-studied areas is the use of MOFs as heterogeneous catalysts for a broad range of organic reactions. In the present review, the employment of MOFs as solid catalysts for the Henry reaction is discussed, and the available literature data from the last decade are grouped. The review is organized with a brief introduction of the importance of Henry reactions and structural properties of MOFs that are suitable for catalysis. The second part of the review discusses the use of MOFs as solid catalysts for the Henry reaction involving metal nodes as active sites, while the third section provides data utilizing basic sites (primary amine, secondary amine, amides and urea-donating sites). While commenting on the catalytic results in these two sections, the advantage of MOFs over other solid catalysts is compared in terms of activity by providing turnover number (TON) values and the structural stability of MOFs during the course of the reaction. The final section provides our views on further directions in this field.

1D Zn(II) Coordination Polymers as Effective Heterogeneous Catalysts in Microwave-Assisted Single-Pot Deacetalization-Knoevenagel Tandem Reactions in Solvent-Free Conditions

The new 1D CPs [Zn(L1)(H2O)4]n.nH2O (1) and [Zn(L2)(H2O)2]n (2) [L1 = 1,1′-(ethane-1,2-diyl)bis(6-oxo-1,6-dihydropyridine-3-carboxylic acid); L2 = 1,1′-(propane-1,3-diyl)bis(6-oxo-1,6-dihydropyridine-3-carboxylic acid)] were prepared from flexible dicarboxylate pro-ligands (H2L1 and H2L2). Both CPs 1 and 2 were characterized by elemental, FTIR, and powder X-ray diffraction analysis. Their geometry and the structural features were unveiled by single-crystal X-ray diffraction analysis. The underlying topology of the CPs was illustrated by the topological analysis of the H-bonded structure of CP 1, which revealed a 3,4,6-connected trinodal net. On the other hand, topological analysis on the hydrogen-bonded network of CP 2 showed a 2,3,3,4,6,7-connected hexanodal net. The thermal stability of the CPs was investigated by thermogravimetric analysis. CPs 1 and 2 act as heterogeneous catalysts in one-pot tandem deacetalization–Knoevenagel condensation reactions under environmentally mild conditions. CPs 1 exhibits a yield of ca. 91% in a microwave-assisted solvent-free medium, whereas a slightly lower yield was obtained for CP 2 (87%) under the same experimental protocol. The recyclability of catalyst 1 was also assessed. To our knowledge, these are the first Zn(II)-based CPs to be applied as heterogeneous catalysts for the above tandem reactions under environmentally friendly conditions.

Architectural and catalytic aspects of designer materials built using metalloligands of pyridine-2,6-dicarboxamide based ligands

This perspective presents the design, synthesis and crystal structures of a large number of architectures constructed using assorted metalloligands of pyridine-2,6-dicarboxamide based ligands. The metalloligands offered various appended functional groups, whereas design strategies included varying both their position and number. A combination of these parameters resulted in the development of assorted architectures including discrete trinuclear and tetranuclear complexes as well as 1D/2D/3D coordination polymers. The metalloligand strategy not only assisted in the construction of ordered crystalline materials with varied dimensionalities but also judiciously allowed the incorporation of Lewis acidic and redox-active secondary metals in the resultant architectures. As a result, such designer architectures illustrated their noteworthy role both as homogenous and heterogeneous catalysts in different organic transformation reactions.

Guedes da Silva MF, Pombeiro AJL. Zn(II)-to-Cu(II) Transmetalation in an Amide Functionalized Complex and Catalytic Applications in Styrene Oxidation and Nitroaldol Coupling

The mononuclear zinc(II) complex cis-[ZnL2(H2O)2] (1; L = 4-(pyridin-3-ylcarbamoyl)benzoate) was synthesized and characterized. By soaking crystals of 1 in a mixture of DMF-H2O solution containing a slight excess of Cu(NO3)2 × 3H2O a transmetalation reaction occurred affording the related copper(II) complex trans-[CuL2(H2O)2] (2). The structures of the compounds were authenticated by single crystal X-ray diffraction revealing, apart from a change in the isomerism, an alteration in the relative orientation of the chelating carboxylate groups and of the pyridine moieties. H-bond interactions stabilize both geometries and expand them into two-dimensional (2D) networks. The transmetalation was confirmed by SEM-EDS analysis. Moreover, the thermodynamic feasibility of the transmetalation is demonstrated by density-functional theory (DFT) studies. The catalytic activities of 1 and 2 for the oxidation of styrene and for the nitroaldol (Henry) C-C coupling reaction were investigated. The copper(II) compound 2 acts as heterogeneous catalyst for the microwave-assisted oxidation of styrene with aqueous hydrogen peroxide, yielding selectively (>99%) benzaldehyde up to 66% of conversion and with a turnover frequency (TOF) of 132 h-1. The zinc(II) complex 1 is the most active catalyst (up to 87% yield) towards the nitroaldol (Henry) coupling reaction between benzaldehyde and nitro-methane or -ethane to afford the corresponding β-nitro alcohols. The reaction of benzaldehyde with nitroethane in the presence of 1 produced 2-nitro-1-phenylpropanol in the syn and the anti diastereoisomeric forms, with a considerable higher selectivity towards the former (66:34).

Crystal structure of poly[diaqua-(μ2-4,4′-bipyridine-κ2 N:N′)-(μ2-3,4,5,6-tetrafluorophthalato-κ2 O:O′)nickel(II)], C18H12F4NiN2O6

C18H12F4NiN2O6, orthorhombic, Pccn (no. 56), a = 7.4650(2) Å, b = 10.6954(2) Å, c = 22.7513(5) Å, V = 1816.49(7) Å3, Z = 4, R gt(F) = 0.0304, wR ref(F 2) = 0.0898, T = 293 K.

Synthesis and catalytic activities of a Zn(ii) based metallomacrocycle and a metal-organic framework towards one-pot deacetalization-Knoevenagel tandem reactions under different strategies: a comparative study

Solvothermal reactions between a pyridine based amide functionalized dicarboxylic acid, 4,4'-{(pyridine-2,6-dicarbonyl)bis(azanediyl)}dibenzoic acid (H2L), and zinc(ii) nitrate in the absence and presence of a base produced the binuclear metallomacrocyclic compound [Zn2(L)2(H2O)4]·2(H2O)·6(DMF) (1) and the metallomacrocyclic based two dimensional MOF [Zn5(L)4(OH)2(H2O)4]n·8n(DMF)·4n(H2O) (2), respectively. Compound 1 bears two tetrahedral Zn(ii) centres, whereas the 2D framework 2 includes a penta-nuclear Zn(ii) cluster as a secondary building block unit, with two of the metal cations assuming a tetrahedral type geometry and the remaining three an octahedral type geometry. The topological analyses reveal that compound 1 has a 2-connected uninodal net and framework 2 has a 2, 8-connected binodal net. These compounds heterogeneously catalyse the tandem deacetalization-Knoevenagel condensation reactions carried out under conventional heating, microwave irradiation or ultrasonic irradiation. Comparative studies show that ultrasonic irradiation (final product yield of 99% after 2 h of reaction time) provides the most favourable method (e.g., microwave irradiation leads to a final product yield of 91% after 3 h of reaction time). Moreover, the catalysts can be reused at least for five consecutive cycles without losing activity significantly.

Hybrid nanomaterials for asymmetric purposes: green enantioselective C–C bond formation by chiralization and multi-functionalization approaches

We present a simple and novel strategy for synthesis of a MOF-based chiral multi-functional hybrid nanomaterial through chiralization and multi-functionalization approaches for asymmetric purposes.

Crystal structure of catena-poly[diaqua-bis(3,4,5,6-tetrabromo-carboxybenzoato-κ1O)-(μ2-4,4′-bipyridine-κ2N:N′)cobalt(II)], C26H14Br8CoN2O10

C26H14Br8CoN2O10, orthorhombic, Pbcn (no. 60), a = 24.3935(3) Å, b = 11.4505(1) Å, c = 11.7004(1) Å, V = 3268.13(6) Å3, Z = 4, Rgt(F) = 0.0313, wRref(F2) = 0.0819, T = 293 K.

Function-Structure Relationship in Metal-Organic Frameworks for Mild, Green, and Fast Catalytic C-C Bond Formation

Tunability in chemical functionality is a promising characteristic of metal-organic frameworks (MOFs), which plays an important role in developing and improving the practical applications of MOFs. Here, we applied this important feature of MOFs to be in line with sustainable development and green chemistry principles through the synthesis of MOF-based heterogeneous organocatalysts. According to our green functionalization strategy, some isostructural MOFs (azine decorated TMU-4 with the formula [Zn(OBA)(BPDB)_0.5]_n·2DMF, azine-methyl functionalized TMU-5 with the formula [Zn(OBA)(BPDH)_0.5]_n·1.5DMF, dihydro-tetrazine decorated TMU-34 with the formula [Zn(OBA)(H₂DPT)_0.5]_n·DMF, and tetrazine functionalized TMU-34(-2H) with the formula [Zn(OBA)(DPT)_0.5]_n·DMF, where H₂OBA = 4,4'-oxybis(benzoic acid), BPDB = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene, BPDH = 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene, H₂DPT = 3,6-di(pyridin-4-yl)-1,4-dihydro-1,2,4,5-tetrazine, and DPT = 3,6-di(pyridin-4-yl)-1,2,4,5-tetrazine) have been applied for mild, green, and fast Knoevenagel condensation. These frameworks display different Lewis basic catalytic activities owing to their different functionality and function accessibility. Contrary to extensive articles published about Knoevenagel condensation, this study involves the rare examples in Knoevenagel condensation with such mild conditions (room temperature and atmospheric pressure) and with a green solution (water as the solvent). Due to the combined synergic effects of the Lewis basicity of TMU-frameworks, the amphoteric and hydrogen bond-participating nature of water molecules, maximum conversion times are reached just after 30 min (for TMU-5) and 60 min (for TMU-34). Stability and recyclability tests show that TMU-5 and TMU-34 are completely stable in water at reaction conditions and can retain their crystallinity, porosity, and functionality even after five cycles without any specific reduction in their catalytic conversion. Since, in many cases, amine decorated MOFs are applied in Knoevenagel catalyzed condensation, this study is beneficial in providing information about the effects of azine and tetrazine functional groups in reactant activation and the acceleration of Knoevenagel condensation.

Hydrosoluble Complexes Bearing Tris(pyrazolyl)methane Sulfonate Ligand: Synthesis, Characterization and Catalytic Activity for Henry Reaction

The catalytic activity of the water-soluble scorpionate coordination compounds [Cu(-NN’O-Tpms)2] (1), [Mn(Tpms)2] (2) and Li[FeCl2(-NN’N’’-Tpms)] (3) [Tpms = tris(pyrazolyl)-methane sulfonate, O3SC(pz)3], were studied towards the (Henry) reaction between benzaldehyde and nitromethane or nitroethane in aqueous medium to afford, respectively, 2-nitro-1-phenylethanol or 2-nitro-1-phenylpropanol, the latter in the syn and the anti diastereoisomeric forms. Complex 1 exhibited the highest activity under the optimum experimental conditions and was used to broaden the scope of the reaction to include several aromatic aldehydes achieving yields up to 94%.

Ni(II)-Aroylhydrazone Complexes as Catalyst Precursors Towards Efficient Solvent-Free Nitroaldol Condensation Reaction

The aroylhydrazone Schiff bases 2-hydroxy-(2-hydroxybenzylidene)benzohydrazide and (2,3-dihydroxybenzylidene)-2-hydroxybenzohydrazide have been used to synthesize the bi- and tri-nuclear Ni(II) complexes [Ni2(L1)2(MeOH)4] (1) and [Ni3(HL2)2(CH3OH)8]· (NO3)2 (2). Both complexes have been characterized by elemental analysis, spectroscopic techniques [IR spectroscopy and electrospray ionization-mass spectrometry (ESI-MS)], and single-crystal X-ray crystallography. The coordination behavior of the two ligands is different in the complexes: The ligand exhibits the keto form in 2, while coordination through enol form was found in 1. Herein, the catalytic activity of 1 and 2 has been compared with the nitroaldol condensation reaction under various conditions. Complex 2 exhibits the highest activity towards solvent-free conditions.

A series of flexible bis(pyridyl)bis(tetrazole)-modulated coordination polymers: construction, electrochemical properties, dye adsorption and magnetic properties

Four new coordination polymers based on three bis(pyridyl)bis(tetrazole) ligands and 4,4′,4′′-benzene-1,3,5-triyltribenzoic acid were synthesized showing electrocatalytic, dye adsorption and antiferromagnetism properties.

Synthesis of Metallomacrocycle and Coordination Polymers with Pyridine-Based Amidocarboxylate Ligands and Their Catalytic Activities towards the Henry and Knoevenagel Reactions

The reactions of 3,3'-{(pyridine-2,6-dicarbonyl)bis(azanediyl)}dibenzoic acid (H2L) with zinc(II), cadmium(II), and samarium(III) nitrates were studied, and the obtained compounds, [Zn(1κO:2κO'-L)(H2O)2] n (1), [Cd(1κO 2:2κO 2-L)(H2O)2]2 ⋅6n H2O⋅ n C4H8O2 ⋅1.5n DMF (2), and [Sm(1κO:2κO'O'':3κO'''-L)(NO3)(H2O)(dmf)] n ⋅ n DMF (3), were characterized by elemental analysis, FTIR spectroscopy, thermogravimetric analysis, and X-ray single-crystal diffraction. Compounds 1 and 3 have 1D zigzag- and double-chain-type structures, respectively, whereas 2 features a dinuclear metallomacrocyclic complex. The ligand (L2-) orients in different conformations, that is, syn-syn for 1 and anti-anti for 2 and 3. Compound 1 is the first example in which the syn-syn conformation for this ligand has been observed. These compounds act as heterogeneous catalysts for the nitroaldol (Henry; in water medium) and Knoevenagel condensation reactions of different aldehydes, and the most effective is zinc coordination polymer 1. Recyclability, heterogeneity, and size-selectivity tests were performed, which showed that the catalyst was highly active over at least four recycling runs.

Enhanced Activity and Enantioselectivity of Henry Reaction by the Postsynthetic Reduction Modification for a Chiral Cu(salen)-Based Metal-Organic Framework

Metal-organic frameworks (MOFs) imbedded privileged molecular catalysts are of particular interest due to their higher catalytic activities derived from the MOFs pore/channel confinement effect, improved lifetime through eliminating intermolecular deactivation pathway, and the recyclability based on their heterogeneity. In this work, a 3D chiral metallosalen-based MOF [Cd₂(Cu(salen))(DMF)₃]·DMF·3H₂O (1) with a 1D open channel was synthesized and characterized by single-crystal X-ray diffraction and other physicochemical methods. Upon postsynthetic reduction modification with NaBH₄, the conversion from imino to amino group on salen cores of 1 generates the reduction product 2 with a more flexible chiral group and more alkaline backbone, meanwhile still maintaining the original porous framework. 2 can be used as an efficient heterogeneous catalyst for the asymmetric Henry reaction with broad substrate applicability and exhibits higher activity and enantioselectivity (ee up to 98%) compared with the unreduced 1. Note that 2 can accelerate the Henry reaction of pyridine-2-carboxaldehyde possessing a potential coordination atom with excellent ee value; however, the homogeneous counterpart does not. In addition, the bulky aldehydes show a decrease in activity but almost the same enantioselectivity with an increase in the molecular size of substrates as a result of the chiral confinement effect of 2, indicating the size-dependent selectivity. To the best of our knowledge, this is the highest enantioselectivity for asymmetric Henry reaction catalyzed by MOF-based catalysts.

Synthesis and structural characterization of a novel dinuclear Cu(ii) complex: an efficient and recyclable bifunctional heterogeneous catalyst for the diastereoselective Henry reaction

We describe the synthesis and structural characterization of a novel dinuclear Cu(ii) complex containing a new flexible mixed pyridine-carboxylate ligand. Single crystal X-ray diffraction reveals its uniqueness with two coordinated water molecules and four uncoordinated pyridyl groups. Utilizing the bifunctional catalytic sites, it has been found to be an efficient, robust and recyclable heterogeneous catalyst for the diastereoselective Henry (nitroaldol) reaction of aldehydes with nitroethane.

A metalloligand appended with benzimidazole rings: tetranuclear [CoZn3] and [CoCd3] complexes and their catalytic applications

A novel Co³⁺-based metalloligand, offering appended benzimidazole rings, has been utilized for the synthesis of catalytically active tetranuclear [CoZn₃] and [CoCd₃] heterometallic coordination complexes.

Ultrasound-assisted biodiesel production by a novel composite of Fe(III)-based MOF and phosphotangestic acid as efficient and reusable catalyst

In this work, esterification of oleic acid by various alcohols is achieved with high yields under ultrasonic irradiation. This reaction performed with a novel heterogeneous catalyst that fabricated by heteropoly acid and Fe(III)-based MOF, namely MIL-53 (Fe). Syntheses of MIL-53 and encapsulation process carry out by ultrasound irradiation at ambient temperature and atmospheric pressure. The prepared composite was characterized by various techniques such as XRD, FT-IR, SEM, BET and ICP that demonstrate excellent catalytic activities, while being highly convenient to synthesize. The obtained results revealed that ultrasound irradiation could be used for the appropriate and rapid biodiesel production.

Construction of 3D homochiral metal–organic frameworks (MOFs) of Cd(ii): selective CO2adsorption and catalytic properties for the Knoevenagel and Henry reaction

Syntheses of two new homochiral, 3D metal–organic frameworks (MOFs) of Cd(ii) and the selective CO₂adsorption and catalytic properties of1has been demonstrated.

Lanthanide metal organic frameworks based on dicarboxyl-functionalized arylhydrazone of barbituric acid: syntheses, structures, luminescence and catalytic cyanosilylation of aldehydes

Ln(iii) MOFs act as recyclable heterogeneous catalysts for the cyanosilylation of aldehydes.

Coordination frameworks containing compounds as catalysts

This article describes a collection of MOF containing compounds as catalysts in a diverse range of organic transformation reactions.

A porous two-dimensional Zn(ii)-coordination polymer exhibiting SC–SC transmetalation with Cu(ii): efficient heterogeneous catalysis for the Henry reaction and detection of nitro explosives

The 2D Zn(ii)-CP, 1Zn and its Cu-analogue 1Cu exhibit efficient catalytic activity for the Henry reaction. 1Zn can be utilized for detecting trace amounts of nitro explosives in DMSO.