Synthesis, Structures, and Heterogeneous Catalytic Applications of {Co3+-Eu3+} and {Co3+-Tb3+} Heterodimetallic Coordination Polymers

Porous Coordination Polymer MOF-808 as an Effective Catalyst to Enhance Sustainable Chemical Processes

The improvement of sustainable chemical processes plays a pivotal role in safe environmental and societal development, for example, by reducing the use of hazardous substances, preventing chemical waste, and improving the efficiency of chemical reactions to obtain added-value compounds. In this context, the porous coordination polymer MOF-808 (MOF, metal-organic framework) was prepared by a straightforward method in water, at room temperature, and was unequivocally characterized by powder X-ray diffraction, vibrational spectroscopy, thermogravimetric analysis, and scanning electron microscopy. MOF-808 material was applied for the first time as catalysts in ring-opening aminolysis reactions of epoxides. It demonstrated high activity and selectivity for reactions of styrene oxide and cyclohexene oxide with aniline, using a very low amount of an eco-sustainable solvent (0.5 mL of EtOH), at 70 °C. Moreover, MOF-808 demonstrated high stability in the catalytic reaction conditions applied, and a notable reuse capacity of up to 20 consecutive reaction cycles, without significant variation in its catalytic performance. In fact, this Zr-based porous coordination polymer prepared by environment-friendly conditions proved to be a novel efficient heterogeneous catalyst, promoting the ring-opening reaction of epoxides under more sustainable conditions, and using a very low amount of catalyst.

Tailored Inorganic-Organic Architectures via Metalloligands

This article discusses the design principles and strategies and the structural outcome of various supramolecular architectures constructed by utilizing well-defined coordination complexes as the metalloligands. We have included selected examples of metalloligands, offering either pyridyl or arylcarboxylic acid groups as the appended functional groups, for illustrating the construction of their supramolecular architectures. Both geometrical position and the number of the appended functional groups emerging from a metalloligand were found to critically regulate the structural aspects and dimensionality of the resultant material. The article concludes by delineating the structure-directing lessions as well as the potential applications of the metalloligand-based supramolecular architectures for the generation of next-level materials.

New Coordination Polymers of Selected Lanthanides with 1,2-Phenylenediacetate Linker: Structures, Thermal and Luminescence Properties

Solvothermal reactions of lanthanide (III) salts with 1,2-phenylenediacetic acid in N,N'-dimethylformamide (DMF) solvent lead to the formation of the metal complexes of the general formula Ln₂(1,2-pda)₃(DMF)₂, where Ln(III) = Pr(1), Sm(2), Eu(3), Tb(4), Dy(5), and Er(6), 1,2-pda = [C₆H₄(CH₂COO)₂]^2-. The compounds were characterized by elemental analysis, powder and single-crystal X-ray diffraction methods, thermal analysis methods (TG-DSC and TG-FTIR), infrared and luminescence spectroscopy. They exhibit structural similarity in the two groups (Pr, Sm, and Eu; Tb, Dy, and Er), which was reflected in their thermal behaviours and spectroscopic properties. Single-crystal X-ray diffraction studies reveal that Sm(2) and Eu(3) complexes form 2D coordination polymers with four crystallographically independent metal centers. Every second lanthanide ion is additionally coordinated by two DMF molecules. The 1,2-phenylenediacetate linker shows different denticity being: penta- and hexadentate while carboxylate groups exhibit bidentate-bridging, bidentate-chelating, and three-dentate bridging-chelating modes. The infrared spectra reflect divergence between these two groups of complexes. The complexes of lighter lanthanides contain in the structure coordinated DMF molecules, while in the structures of heavier complexes, DMF molecules appear in the inner and outer coordination sphere. Both carboxylate groups are deprotonated and engaged in the coordination of metal centers but in different ways in such groups of complexes. In the groups, the thermal decomposition of the isostructural complexes occurs similarly. Pyrolysis of complexes takes place with the formation of such gaseous products as DMF, carbon oxides, ortho-xylene, ethers, water, carboxylic acids, and esters. The complexes of Eu and Tb exhibit characteristic luminescence in the VIS region, while the erbium complex emits NIR wavelength.

Effect of pyridyl donors from organic ligands versus metalloligands on material design

This review illustrates designs and structures of various coordination frameworks constructed using assorted organic ligands and metalloligands offering pyridyl donors to evaluate the impact of flexibility versus rigidity on material design.

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.

Template effect of innocent and coordinating anions on the formation of interpenetrated 2D and 3D networks: methyl orange and iodine sorption studies

A pyridyl based Schiff base resulted in a 2D staircase network (CP1) with Cd(ii) when ClO₄⁻ is the counter anion while the use of benzene-1,3-disulphonate counter anion resulted in a novel 3D Cd(ii) coordination polymer with threefold interpenetration (CP2).

Copper based coordination polymers based on metalloligands: utilization as heterogeneous oxidation catalysts

This work presents two copper-based coordination polymers and their utilization as stable, reusable and heterogeneous catalysts for the epoxidation of olefins using O₂ and for peroxide-mediated oxidation of benzyl alcohols under solvent-free conditions.

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.

Carbon-sulphur cross coupling reactions catalyzed by nickel-based coordination polymers based on metalloligands

This work illustrates two Ni²⁺based coordination polymers and their utilization as reusable and heterogeneous catalysts for the C–S cross coupling reactions between assorted aromatic halides with thiophenol, cyclohexanethiol and ethanethiol.

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.

Catalytic alcoholysis of epoxides using metal-free cucurbituril-based solids

Cucurbit[7]uril containing entrapped hydronium ions possesses unique acid properties as demonstrated by its ability to catalyse alcoholysis reactions under mild conditions.

Lanthanide-based coordination polymers as promising heterogeneous catalysts for ring-opening reactions

Eu and Tb based coordination polymers function as reusable heterogeneous catalysts for ring-opening reactions with amines, alcohols, thiols, and azides as nucleophiles.

Heterometallic coordination polymers: syntheses, structures and heterogeneous catalytic applications

Heterometallic coordination polymers function as heterogeneous catalysts for various organic transformation reactions via preferential interaction with the substrates.

Mononuclear complexes of amide-based ligands containing appended functional groups: role of secondary coordination spheres on catalysis

Coordination complexes of amide-based ligands with appended heterocyclic rings create a hydrogen bonding cavity that effectively binds the substrate(s). Such cavity-based complexes function as reusable and heterogeneous catalysts for various organic transformations.

Synthesis, characterization, and antibacterial and anticancer screening of {M(2+)-Co (3+)-M (2+)} and {Co (3+)-M (2+)} (M is Zn, Cd, Hg) heterometallic complexes

The cobalt(III) complexes Et(4)N[Co(L(1))(2)] and [Co(L(2))(3)] [H(2)L(1) is 2,6-bis(N-(2-pyridyl)carbamoyl)pyridine and HL(2) is 2-(N-(2-pyridyl)carbamoyl)pyridine] were used as the building blocks for preparing a series of {M(2+)-Co(3+)-M(2+)} (where M is Zn, Cd, or Hg) and {Co(3+)-M(2+)} (where M is Zn or Cd) heterometallic complexes. All heterometallic complexes were characterized using a host of spectroscopic methods (IR, NMR, and UV/vis spectroscopy and mass spectrometry), elemental analysis, and conductivity measurements. One of the representative compounds, {Hg(2+)-Co(3+)-Hg(2+)}, was characterized crystallographically, and it was revealed that two Hg(II) ions are coordinated within the clefts created by the building block Et(4)N[Co(L(1))(2)]. The results of screening for anticancer activity against the human brain tumor U87 cell line and antibacterial activity against a range of resistant (Pseudomonas aeruginosa and Proteus vulgaris) as well as standard (Staphylococcus aureus SA 96, P. aeruginosa MTCC 1688, Klebsiella planticola MTCC 2272, and Escherichia coli T7) bacterial strains indicate promising activities. Notably, the observed activity was found to vary with the type of building block and the secondary metal ion present in the heterometallic complex. Treatment-induced cell death [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, MTT and macrocolony assay), growth inhibition, cytogenetic damage, cell cycle delay, and apoptosis were studied as the parameters for cellular response.