New Palladium - ZrO2 Nano-Architectures from Thermal Transformation of UiO-66-NH2 for Carbonylative Suzuki and Hydrogenation Reactions.

The new nanocomposites, Pd/C/ZrO2 , PdO/ZrO2, and Pd/PdO/ZrO2 , were prepared by thermal conversion of Pd@UiO-66-Zr-NH2 (MOF) in nitrogen or air atmosphere. The presence of Pd nanoparticles, uniformly distributed on the ZrO2 or C/ZrO2 matrix, was evidenced by transmission electron microscopy, scanning electron microscopy (SEM), Raman and X-ray Photoelectron Spectroscopy (XPS) methods. All pyrolysed composites retained the shape of the MOF template. They catalyze carbonylative Suzuki coupling under 1 atm CO with an efficiency significantly higher than the original Pd@UiO-66-Zr-NH2 . The most active PdO/ZrO2 composite, formed benzophenone with TOF up to 1600 h-1 , while by using Pd@UiO-66-Zr-NH2 , much lower TOF values, 51-95 h-1 , were achieved. After the reaction, PdO/ZrO2 was recovered with the same composition and catalytic activity. Very good results were also obtained in the transfer hydrogenation of benzophenones to alcohols with Pd/C/ZrO2 and PdO/ZrO2 catalysts under microwave irradiation.

Magnesium Exchanged Zirconium Metal-Organic Frameworks with Improved Detoxification Properties of Nerve Agents.

UiO-66, MOF-808 and NU-1000 metal-organic frameworks exhibit a differentiated reactivity toward [Mg(OMe)2(MeOH)2]4 related to their pore accessibility. Microporous UiO-66 remains unchanged while mesoporous MOF-808 and hierarchical micro/mesoporous NU-1000 materials yield doped systems containing exposed MgZr5O2(OH)6 clusters in the mesoporous cavities. This modification is responsible for a remarkable enhancement of the catalytic activity toward the hydrolytic degradation of P-F and P-S bonds of toxic nerve agents, at room temperature, in unbuffered aqueous solutions.

A new MOF@bioactive glass composite reinforced with silver nanoparticles - a new approach to designing antibacterial biomaterials.

Multifunctional materials that combine antimicrobial properties with the ability to stimulate bone formation are needed to overcome the problem of infected bone defects. As a novel approach, a new composite based on bioactive glass nanoparticles in a simple system of SiO2-CaO (BG) coated with NH4[Cu3(µ3-OH)(µ3-4-carboxypyrazolato)3] (Cu-MOF) with additionally anchored silver nanoparticles (AgNPs) was proposed. Ag@Cu-MOF@BG obtained by the spin coating approach in the form of a disc was characterized using PXRD, ATR-FTIR, XPS, ICP-OES, and TEM. Importantly, the material retained its bioactivity, although ion exchange in the bioactive glass administered as a disc is limited. Hydroxyapatite (HA) formation was identified in TEM images after 7 days of immersion of the composite in a physiological-like buffer (pH 7.4, 37 °C). The Cu and Ag contents of Ag@Cu-MOF@BG were as low as 0.013 and 0.018 wt% respectively, but the slow release of the AgNPs ensured its antibacterial nature. Ag@Cu-MOF@BG exhibited antibacterial activity against all tested bacteria (E. coli, S. aureus, P. aeruginosa, and K. pneumoniae) with the diameter of the inhibition zones of their growth between 8 and 10 mm and the reduction index determined to be ≥3. Moreover, the biocompatibility of the new composite has been demonstrated, as shown by cell culture assays with human dermal fibroblasts (HDFs). The results from the migration test also proved that the HDF cell's phenotypic properties were not changed, and the cell adhesion and migration ability were the same as in control indirect assays.

First dinuclear rhodium(II) complexes with triazolopyrimidines and the prospect of their potential biological use.

Five novel rhodium(II) complexes of general formula [Rh2(µ-OOCCH3)4L2], where L is a triazolopyrimidine derivative, in particular dimethyl-1,2,4-triazolo[1,5-a]pyrimidine (dmtp) for (1), 5,7-diethyl-1,2,4-triazolo[1,5-a]pyrimidine (detp) for (2), 7-isobutyl-5-methyl-1,2,4-triazolo[1,5-a]pyrimidine (ibmtp) for (3), 7-hydroxy-5-methyl-1,2,4-triazolo[1,5-a]pyrimidine (HmtpO) for (4) and 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp) for (5) are reported. These first representatives of paddle-wheel dirhodium complexes with triazolopyrimidines have been characterized by IR and NMR spectroscopy as well as by single-crystal X-ray diffraction studies. Three of the new complexes (1), (2) and (5) were thoroughly screened in vitro for their cytotoxicity against human breast cancer cell line MCF-7 and L929 murine fibroblast cells. Favorably, they show significantly less effective inhibition on the cell growth of L929 than cisplatin under identical conditions. Complexes (1) and (5) display moderate cytotoxic activity (IC50 = 16.3-21.5 µM) against MCF-7 cells which is induced via reactive oxygen species-independent pathways. Extensive studies of rhodium complexes (1), (2) and (5) against microorganisms have shown that the tested compounds exhibit antibacterial activity against Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) while (5) significantly inhibited the growth of Malassezia furfur. The highest antibacterial, and antifungal activity, was observed for (5).

Reactivity of nano-size zinc powder in the aqueous solution of [FeIII(edta)(H2O)].

Nitrogen mono-oxide and sulfur dioxide can be removed by simultaneous absorption into aqueous mixed solutions of sulfite and [FeII(edta)]H2O)]2-, ferrous ion coordinated to an anion of ethylene-diaminetetraacetic acid (EDTA or edta). In the industrial system with coexisting oxygen in the gas phase, [FeII(edta)](H2O)]2- complex is oxidized to [FeIII(edta)](H2O)]- by molecular oxygen. Because the ferric complex has no capability for reaction with NO, the suppression of this undesired oxidation process is a very important technological problem to be overcome. In our preceding work, we discussed the reduction kinetics of ferric ion by metal powder on the basis of the kinetic data regarding the ferric ion reduction in aqueous solutions of [FeIII(edta)](H2O)]- containing aluminum, tin or zinc powders. Zinc powder of normal size was recognized as an effective reducing agent. In the present work, augmentation of reducing capability of zinc powder was examined more. The rate of reduction of nano-size zinc powder was found to be about 11 times higher than that of normal-size zinc one.