A Cd(II) metal–organic framework based on semi-rigid ligand 3,5-(4-carboxybenzyloxy) benzoic acid with high stability by intramolecular hydrogen-bonding

A new trinuclear cluster-based Cd(II) compound: photocatalytic property and nursing application values on the bacterial infection

A new Cd(II) coordination polymer with the formula of {[(CH3)2NH2][Cd3(NH2-bdc)3(btz)(H2O)]} n (1 NH2-H2bdc = 2-aminoterephthalic acid, Hbtz = 1 H-benzotriazole) was produced and then it was structurally characterized through powder X-ray diffraction (PXRD), the analysis of X-ray single-crystal diffraction, along with elemental analysis (EA). The photocatalytic property investigations indicate that compound 1 exhibits good activity for photodegradation of methyl violet (MV) with 60.7% of MV removal in 40 min under room temperature. Furthermore, the assessment of the compound's treatment activity and nursing application values on the bacterial infection was conducted and its corresponding mechanism was also studied. Evaluation of the in vitro hemolysis of the compound was determined by measuring the degree of red blood cell lysis and hemoglobin release. The effect of new compounds on the relative proliferation rate of L-929 cells was measured by MTT assay. The ELISA detection kit showed that the compound could reduce the TNF-α and IL-1β content released into plasma. Next, the inhibitory activity of the compound on the bacterial survival gene expression was also proved with real-time RT-PCR. The hemolysis rate of the new compound to blood is 3.4%, which is less than the standard 5%, which is non-hemolytic reaction. The compound also has no obvious cytotoxicity and has good cell compatibility.

Intramolecular hydrogen bond-induced high chemical stability of metal–organic frameworks

Intramolecular hydrogen bonds in ligands restrict the rotation of carboxyl groups and consequently enhance the chemical stability of MOFs.

Two water-stable lanthanide metal-organic frameworks with oxygen-rich channels for fluorescence sensing of Fe(iii) ions in aqueous solution

The development of metal-organic framework sensors with excellent stability under harsh physical and chemical conditions is of great significance in practical applications. Two isostructural lanthanide-organic frameworks, Ln-MOF ({Ln(L)(H2O)(DMA)}n, {FJU-13-Ln, Ln = Eu, Tb } (H3L = 3,5-(4-carboxybenzyloxy)benzoic acid)), were found to display exceptional stability, not only being stable in both acidic and basic aqueous solutions (pH 3-11), but also maintaining good robustness in boiling water and after activation. Furthermore, the plentiful oxygen atoms in the oxygen-rich channels of FJU-13-Eu and FJU-13-Tb acted as Lewis base sites for sensing metal ions, exhibiting high sensitivity (Stern-Volmer constant, KSV = 2.03 × 104 M-1 for FJU-13a-Eu and KSV = 2.11 × 104 M-1 for FJU-13a-Tb) and low detection limits (1.41 μM for FJU-13a-Eu and 1.01 μM for FJU-13a-Tb) for Fe3+ ions. This suggests that the two Ln-MOFs are promising fluorescent sensors for Fe3+ ion detection.

Robustness, Selective Gas Separation, and Nitrobenzene Sensing on Two Isomers of Cadmium Metal-Organic Frameworks Containing Various Metal-O-Metal Chains

Poor stability has been one of the major difficulties affecting to the practical application of metal-organic frameworks (MOFs). In this work, we obtained two 3D structurally isomeric Cd-MOFs, {[Cd₆(NH₂Me₂)₂(PTB)₄(HCOO)₂(H₂O)]·(DMF)₁₃·(H₂O)₄} _n (FJU-35) and {[Cd₆(NH₂Me₂)₂(PTB)₄(HCOO)₂]·(DMF)₆·(H₂O)₂} _n (FJU-36) (H₃PTB = pyridine-2,4,6-tribenzoic acid) containing different Cd^II-O-Cd^II chains by varying the addition agents. FJU-35 with coordinated solvent and formate in asymmetric μ₃-η¹:η² coordination mode within the Cd^II-O-Cd^II chains is vulnerable to external attacks and is apt to collapse after activation, while FJU-36 with no coordinated solvent in the Cd^II-O-Cd^II chains but fully protected by the carboxylates from the ligands and the symmetric formate in the coordination mode μ₃-η²:η² is stable, and its activated sample shows efficient separation of C₂H₂/CH₄ and C₂H₂/CO₂ mixtures. Conversely, FJU-35 with more vulnerability is more sensitive to the detection of nitrobenzene than FJU-36.