This work describes, the decoration of Ti/TiO 2 nanotubes by nanoparticles of ZIF-8 (zeolite imidazole framework-8) grown using a layer-by-layer process. Morphological and crystallographic analyses showed that the TiO 2 nanotubes were coated with ZIF-8 nanoparticles around 50 nm in size. Curves of I ph vs. E showed that the incorporation of ZIF-8 at Ti/TiO 2 electrodes increased the photocurrent and that the values were dramatically increased in solution saturated with CO 2. The CO 2 adsorbed on the ZIF-8 formed stable carbamates, as demonstrated by spectroscopic and voltammetric assays. Photoelectrocatalytic reduction of CO 2 at Ti/TiO 2 NT-ZIF-8 electrodes resulted in formation of up to 10 mmol L −1 of ethanol and 0.7 mmol L −1 of methanol in 0.1 mol L −1 Na 2 SO 4 , at E app of +0.1 V, under UV-vis irradiation at room temperature. Our findings open up new applications of metal-organic frameworks (MOFs) in photoelectrocatalysis for the highly efficient preconcentration and conversion of CO 2 in aqueous media at ambient temperature.

Iron-binding peptides are an alternative for increasing the bioavailability of iron and to decreasing its pro-oxidant effect. This study aimed to synthesize and characterize peptide-iron complexes using FeCl or FeSO as the iron precursor compounds. Whey protein isolate (WPI), WPI hydrolyzed with pancreatin, and its fractions obtained via ultrafiltration (cut-off 5kDa) were used as ligands. The fluorescence intensity of the ligands significantly decreased as the iron concentration increased as a result of metal coordination with the iron-binding sites, which may have led to changes in the microenvironment of tryptophan. For both iron precursor compounds, the primary iron-binding site was carboxylate groups, and the linkage occurred via a bidentate coordination mode with two vibrational modes assigned to the COOFe linkage. However, infrared spectroscopy and thermal analysis results showed that the dynamics of the interaction is different for the iron precursor. The iron source may be of great importance because it may impact iron absorption and the pro-oxidant effect of the mineral.

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Metal−organic frameworks (MOFs) offer many opportunities for applications across biology and medicine. Their wide range of chemical composition makes toxicologically acceptable formulation possible, and their high level of functionality enables possible applications as delivery systems for therapeutics agents. Surface modifications have been used in drug delivery systems to minimize their interaction with the bulk, improving their specificity as targeted carriers. Herein, we discuss a strategy to achieve a tumor-targeting drug-loaded MOF using "click" chemistry to anchor functional folic acid (FA) molecules on the surface of N 3bio-MOF-100. Using curcumin (CCM) as an anticancer drug, we observed drug loading encapsulation efficiencies (DLEs) of 24.02 and 25.64% after soaking N 3 -bio-MOF-100 in CCM solutions for 1 day and 3 days, respectively. The success of postsynthetic modification of FA was confirmed by 1 H NMR spectroscopy, Fourier transform infrared spectroscopy (FTIR), and liquid chromatography−mass spectrometry (LC-MS). The stimuli-responsive drug release studies demonstrated an increase of CCM released under acidic microenvironments. Moreover, the cell viability assay was performed on the 4T1 (breast cancer) cell line in the presence of CCM@N 3 -bio-MOF-100 and CCM@N 3 -bio-MOF-100/FA carriers to confirm its biological compatibility. In addition, a cellular uptake study was conducted to evaluate the targeting of tumor cells.

Lanthanide-based coordination compounds of molecular formula [Ln(keto) 3 (H 2 O)], where Ln¼ Gd, Eu and keto¼ ketoprofen, were synthesized and their photoluminescence features were detailed in the 12-300 K interval. The emission spectra of [Eu(keto) 3 (H 2 O)] reveal a strong dependence with the temperature, well-illustrated by an unusual large blue-shift (∼17 cm À 1) of the 5 D 0-7 F 0 transition as the temperature is raised. The arithmetic difference between the absorption spectrum of [Eu(keto) 3 (H 2 O)] with that of [Gd(keto) 3 (H 2 O)] pointed out the presence of a ligand-to-metal charge transfer (LMCT) band (320-370 nm). From the [Gd(keto) 3 (H 2 O)] phosphorescence the energy of the keto-related triplet states was determined showing a large overlap with the intra-4f 6 levels and a strong electron-phonon coupling. The high-resonance between the LMCT and triplet states and the Eu 3 þ levels leads to a strong dependence of the 5 D 0 lifetime value, typical of the presence of operative energy transfer processes.