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Two binuclear Gadolinium(III) (Gd) complex [Gd2(L1)2(H2L3)2(NO3)2] (1) and [Gd2(L2)2(H2L3)2(NO3)2] (2) were obtained by using 2‐hydroxybenzaldehyde or 2‐hydroxy‐1‐naphthaldehyde, 2‐aminophenol, pyridin‐2‐ylmethanamine and Gd(NO3)3 ⋅ 6H2O in CH3CN (H2L1=(E)‐2‐((2‐hydroxybenzylidene)amino)phenol, H2L2=(E)‐1‐(((2‐hydroxyphenyl)imino)methyl)naphthalen‐2‐ol, H2L3=pyridin‐2‐ylmethanamine). Structural analysis suggests that all the ligands as protective units protect the central Gd(III) ions at the periphery. Magnetization studies exhibited magnetocaloric effect of 14.45 J ⋅ kg−1 ⋅ K−1 at 4 K under ΔH=7 T for complex 1 and 12.69 J ⋅ kg−1 ⋅ K−1 at 2 K under ΔH=7 T for complex 2. In complexes 1 and 2, although the coordination configurations are the same, the significant difference in MCE may be due to the adjustments of the peripheral ligands leading to changes in the coordination field strength. The electron affinity of the ligands can impact the interaction between the ligands and Gd(III) ions. [ABSTRACT FROM AUTHOR]

Two copper (II) complexes based on the mixed ligand system were synthesized and structurally characterized. The molecular formulae for complex (1), [Cu2L1L′] and complex (2), [CuL2L′] were determined based on analytical data, molar conductance, and thermal analysis results. The optimized structures of complexes (1) and (2) were determined by magnetic and spectroscopic measurements (FTIR, UV–Vis, and ESR) and confirmed by processing powder X‐ray diffraction data by Expo 2014 software. The geometry index (τ5), determined by ESR spectra and structural analysis based on powder X‐ray, demonstrates the square pyramidal geometry of the Cu (II) center of [Cu2L1L′] and [CuL2L′]. Cyclic voltammetry measurements were performed to elucidate the relationship between the redox properties of (1) and (2) and their oxidase‐mimicking catalytic activity. Catalytic aerobic oxidation of the polyphenols 3,5‐di‐tert‐butylcatechol (3,5‐DTBCH2), 4‐nitrocatechol, and 2‐aminophenol (2‐APH3) was studied by stopped‐flow technique. Promising catechol oxidase (COX) and phenoxazinone synthase (PHS) mimetic activity have been demonstrated for (1) and (2). Electrochemical data were used to determine the free energy (ΔG°) or driving force (−λ), and their correlation with the oxidase mimetic activity of(1) and (2) was examined. Several experimental procedures have been performed that have helped describe the catalytic mechanisms of the catalytic reactions taking place. [ABSTRACT FROM AUTHOR]

Metal–organic framework (MOF) membranes with apparent molecular sieving effects have great potential for gas separation. However, their application in light‐gas separation (e.g., CO2/CH4 and H2/CH4) remains challenging due to their enlarged pore structures under transmembrane pressure. In this work, a series of MOF membranes constructed from dual‐wing (DW) ligands including 2‐chloromethylbenzimidazole, 2‐methylbenzimidazole, 2‐ethylbenzimidazole, and 2‐phenylbenzimidazole are reported, to finely tune apertures and enhance molecule sieving property for small‐size gases. These DW‐ligands provide steric resistance in two directions perpendicular to the coordination bond, leading to a much finer pore structure. The introduction of the DW‐ligands endows the DW/ZIF‐8 membranes with an adjustable bottleneck door for regulating gas diffusion, blocking the transport of large‐sized CH4 while allowing small‐sized H2 and CO2 to permeate. The membranes show significantly improved molecular sieving property with a CO2/CH4 mixed‐gas selectivity of 58.6 in the case of 2‐chloromethylbenzimidazole23/ZIF‐8, which represents the highest value among the reported ZIF membranes. This membrane also exhibits exceptional separation performance for H2/CH4 and H2/C3H8 with separation factors of 430 and 34341, which are the highest values among the reported MOF membranes. This study presents a facile and efficient strategy for regulating MOF aperture and constructing high‐performance membranes for natural gas separation. [ABSTRACT FROM AUTHOR]

The current work reports the synthesis of mixed ligand‐metal complexes of (2‐(2‐oxoacenaphthylen‐1 ylidene)hydrazinecarbothioamide) (L1) and carbamothioyl‐2‐chloronicotinohydrazonic acid (L2) and imidazole (im), triphenylphosphine (PPh3) and pyridine (py) ligands with Cu (II), Zn (II), Fe (II) and Co (II) salts.The chacterization was done through FT‐IR, NMR, UV‐visible, and elemental analysis. The X‐ray diffraction (XRD) patterns of [Cu(L1)(im)2(SO4)] demonstrated the crystalline morphology. In the FT‐IR spectra of the ligands, the characteristic frequencies corresponding to ν(C=N) (imine) and ν(C=S) (thiocarbonyl) were observed around 1650 and 1130 cm−1 respectively, which shifted upon complexation. In the 1H NMR spectra, the peak due to the NH proton was observed downfield, whereas that of ‐NH2 was observed comparatively upfield owing to its secondary amine nature. The molecular docking was performed against transforming growth beta (tgf‐β), protease of SARS‐CoV‐2 (Mpro) and aspartate kinase (Asp) kinase.The molecular simulation with the docked complex of [Zn(L2)(py)2(SO4)] and [Zn(L1)(PPh3)2(SO4)] with Asp kinase showed significant stability during the simulation time of 100 ns. The relative free energies of the simulated complexes were calculated with the molecular mechanics Poison‐Boltmann surface area (MM‐PBSA). The complexes were tested against ten bacterial strains and showed enhanced antibacterial activity than the ligands. [Cu(L1)(im)2(SO4)], [Zn(L1)(im)2(SO4)], [Fe(L1)(im)2(SO4)] and [Co(L1)(im)2(Cl2)] were found to be active against E.coli. [ABSTRACT FROM AUTHOR]

[Display omitted] • The crystal structure of new mononuclear, mixed-ligand Co(II) complex is determined. • The maximum adsorption capacity of the complex reached 194.4 mg/g for Rhodamine B dye. • The plausible mechanism is electrostatic interaction, hydrogen bonding, and π-π interaction. • The kinetic study investigation provided, Q e = 207.3 mg/g. A new mixed-ligand cobalt complex with the general formula [Co(H 2 O)(teaH 3)(4-NBA)]·(4-NBA)·H 2 O (1), where (teaH 3 = triethanolamine and 4-NBA = 4-nitrobenzoate), has been successfully synthesized and characterized. In this complex, triethanolamine acts as a tetradentate ligand and the 4-NBA act as monodentate ligands. The cobalt metal ion in the complex has a coordination number of 6 with a slightly distorted octahedral geometry. Furthermore, some intramolecular and intermolecular interactions have been observed in 1. Moreover, the kinetic studies on the rate of adsorption confirm that the Pseudo Second Order model accurately predicted the absorption of RhB by the complex. The higher R-squared value and the close agreement between the calculated (Q e = 207.3 mg/g) and experimental (194.4 mg/g) values indicate a satisfactory match. The hydrogen bonding interactions and other weaker electrostatic interactions between the complex and the RhB molecule enhance this adsorption. [ABSTRACT FROM AUTHOR]

In this work, a sulfonated UiO-66 was synthesized and modified with a mixed ligand strategy using 2-amino terephthalic acid as a second linker. The X-ray diffraction (XRD) diffractogram shows a transition from an amorphous to a crystalline pattern with the addition of a second linker. The Fourier transforms infrared spectroscopy spectra show the presence of new peaks at 1255, 1382, and 1426 cm−1, which refer to N-H and C-N stretching. All the mixed ligand samples showed stable thermal stability as the pristine UiO-66-SO 3 H sample. The field emission scanning electron microscopy analysis also showed a morphological change from a round-like shape (UiO-66-SO 3 H) to a triangular-based pyramid shape (UiO-66-SO 3 H-NH 2 -0.85). The nitrogen physisorption analyses showed a significant increase in the BET surface area of UiO-66-SO 3 H-NH 2 -0.85 (706 m2/g) from UiO-66-SO 3 H (16 m2/g). The CO 2 -TPD results demonstrated that the greater formation of medium basic sites (monodentate carbonate and bidentate carbonate species) is due to the increase in the amount of the second linker. Furthermore, the UiO-66-SO 3 H-NH 2 -0.85 showed CO 2 adsorption of 2.17 mmol/g, five times higher than UiO-66-SO 3 H (0.43 mmol/g). Both samples also showed excellent recyclability up to ten cycles. After being reused for ten cycles, the sample preserved the characteristics of the XRD pattern and crystallinity, functional groups, and thermal stability. For the water and pH stability studies, UiO-66-SO 3 H and UiO-66-SO 3 H-NH 2 -0.85 maintained the original XRD patterns, a high BET surface area, and good CO 2 adsorption in water and acid environments. [Display omitted] • Introducing the amino group as a second linker into UiO-66-SO 3 H is an efficient approach. • The highest CO 2 adsorption was observed on UiO-66-SO 3 H-NH 2 -0.85 of 2.17 mmol/g at 25 ˚C and 1 atm. • UiO-66-SO 3 H and UiO-66-SO 3 H-NH 2 -0.85 maintain the recyclability for up to ten cycles. • BET surface area and polar functional groups played important roles in CO 2 adsorption performance. • UiO-66-SO 3 H and UiO-66-SO 3 H-NH 2 -0.85 showed good water and chemical stability. [ABSTRACT FROM AUTHOR]

By introducing functional groups into the isophthalate ligand to decorate the pore of the MOFs, gas adsorption and separation performance can be tunable. In this paper, two isostructural 2D Co-MOFs, [Co(5-MIA)(bpy)]·H 2 O (1) and [Co(5-EIA)(bpy)]·H 2 O (2) (5-H 2 MIA = 5-methoxyl-isophthalic acid; 5-H 2 EIA = 5-ethyoxyl-isophthalic acid; bpy = 4,4′-bipyridine), with different functionalized pore surfaces and channel sizes were designed and constructed. The structures and performance of the two Co-MOFs were analyzed by SCXRD, PXRD, IR, TGA, and gas sorption (CO 2 , C 2 H 2 , CH 4 , CO, and N 2). Attributed to the methoxyl of isophthalate skeleton, 1a (activated 1) shows enhanced CO 2 uptake over other gases. In spite of decreased pore sizes (3.49 Å) compared with 2a (4.38 Å), the CO 2 uptake of 1a (43.41 cm3 g−1) is larger than that of 2a (22.39 cm3 g−1) at 298 K and 100 kPa. Compound 1 incorporates methoxyl groups into the narrow channel, and exhibits the cooperative effect of CO 2 -preferential due to adsorbent-adsorbate coactions and size sieving. GCMC simulation has been used to explore the adsorption coactions of CO 2 and 1 , and the results confirmed that the methoxyl groups in the channel are the main binding sites of CO 2. At ambient temperature and 100 kPa, the IAST selectivities of CO 2 /C 2 H 2 (1:1), CO 2 /CH 4 (1:1), C 2 H 2 /CH 4 (1:1), CO 2 /CO (1:2) and CO 2 /N 2 (15:85) on 1a were 2.6, 39.3, 13.3, 282 and 1433, respectively. The easy activation and regeneration, excellent thermal and humidity stability, and good reusability, make 1 a hopeful adsorbent for adsorption and separation of CO 2. By introducing functional groups into the isophthalate ligand to decorate the pore of the MOFs, gas adsorption and separation performance can be tunable. Two isostructural 2D Co-MOFs with different functionalized pore surfaces and channel sizes were constructed and show different C 2 H 2 /CH 4 and C 2 H 2 /CO 2 gas separation properties. [Display omitted] • Title compound represent the first example of 3D MOF based on 5-H 2 MIA and bpy. • 1a (activated 1) shows enhanced CO 2 uptake over C 2 H 2 , CH 4 , CO and N 2. • 1a shows an excellent reuse performance. [ABSTRACT FROM AUTHOR]