Reusable and Highly Active Copper-Based Lacunary-type Polyoxometalate (LPMo-Cu) as an Effective Catalyst for Nitroarene Reduction in Aqueous Solution.

Lacunary polyoxometalates (LPOMs), a class of anionic metal oxide clusters, are promising materials as catalysts, photocatalysts, and electrocatalysts. Designing and functionalizing this type of compound are key factors for the discovery and development of novel materials. Herein, a new lacunary polyoxometalate-based compound was designed as a heterogeneous catalyst, prepared through functionalization of a lacunary Keggin-type polyoxometalate, i.e., [PMo11O39]7-, with 3-aminopropyltrimethoxysilane (APTS) and 2-pyridine carboxaldehyde. Subsequent reactions of this compound with Cu2+ ions led to the desired catalyst, LPMo-Cu. The catalytic activity of the obtained LPMo-Cu was examined in nitroarene reduction using sodium borohydride as a reducing agent in aqueous solution. It was specified that the synthesized LPMo-Cu exhibits high catalytic efficiency in the reduction of a wide variety of nitroarenes in a short time (5 min). Furthermore, the stability and recoverability of the prepared material were proved as a result of four consecutive reduction cycles without a significant decrease in its efficiency.

Layer-By-Layer Synthesis of the pH-Responsive Hollow Microcapsule and Investigation of Its Drug Delivery and Anticancer Properties.

Multilayered pH-responsive hollow microcapsules with non-toxicity and biological specificity advantages were prepared from two kinds of polymers i.e., chitosan (CH) and poly (ethylene glycol dimethacrylate-co-methacrylic acid) (PE) via layer-by-layer (LbL) method, which is followed by subsequent removal of silica core. The hollow nature of obtained spherical microcapsules was found by transmission electron microscopy (TEM). The microcapsules were prepared as gemcitabine (GM) and curcumin (CR) carriers. The drugs have been loaded within the microcapsules during or after the synthetic procedure. Although acceptable loading efficiencies (LE) were obtained in both methods, the amount of drug loaded during the synthesis method is relatively higher. Values above 78% and 87%, for releasing efficiency (RE%) and encapsulation efficiency (EE%), respectively, demonstrate the high potential of the prepared microcapsules for drug delivery. In addition, the difference between the amount of drug released in acidic and neutral pH indicates the pH-responsivity of the prepared microcapsules. Moreover, the dose-dependent high cytotoxicity effect of the prepared microcapsules was observed on the HCT116 colorectal carcinoma cells.

Sustainable Coordination Polymer-Based Catalyst and Its Application in the Nitroaromatic Hydrogenation under Mild Conditions.

Nitroarene reduction has played a crucial role in the environment remediation and public health. However, few research studies have been undertaken regarding the use of infinite coordination polymer-based catalysts in this process. Herein, we are looking for a way to catalyze the reduction of nitroarenes using a new and well-designed coordination polymer-based palladium catalyst. The Co-BDC-NH2 coordination polymer was prepared through a co-precipitation reaction between 2-amino-1,4-benzenedicarboxylic acid as a linker and the cobalt cation as a node. Functionalization of the prepared Co-BDC-NH2 with 2-pyridinecarboxaldehyde and subsequent metallation with a Pd cation led to the formation of the final catalyst, i.e., Co-BDC-NH2-py-Pd. It has been specified that palladium species substantially contribute to the reduction of nitroarenes in the presence of hydrazine hydrate (N2H4·H2O). The highest conversion (100%) of nitroarenes to the corresponding amines was achieved under relatively mild conditions. This heterogeneous catalyst was able to catalyze the reduction of nitroarenes to desired products without changing other substituents. The reusability and stability of the catalyst were confirmed through four consecutive reduction tests without a major decrease in catalytic activity.

Designing a New Efficient Photocatalyst Based on Functionalization of Zn-Infinite Coordination Polymer with Ru(acac)3 Complex for Dye Degradation in Aqueous Solutions: Charge Separation Effect.

A new Zn-containing infinite coordination polymer, Zn-ICP, functionalized with Ru(acac)3 complex was designed and utilized as an efficient visible light photocatalyst for dye degradation in aqueous solutions. Incorporation of Ru(acac)3 not only extended the light absorption of the Zn-ICP to the visible region but also led to electron-hole separation. Upon visible light illumination, photoinduced electron transfer from excited state of Zn-ICP to Ru(acac)3 occurred, resulting in electron-hole separation as indicated by photoluminescence and electrochemical impedance spectroscopy. The obtained Ru-Zn-ICP revealed enhanced visible light photocatalytic activity in degradation of organic pollutants compared to pristine Zn-ICP owing to photoinduced electron transfer in the Ru-Zn-ICP system and efficient separation of photogenerated electron-hole pairs. The prepared Ru-Zn-ICP photocatalyst was readily recycled without major loss of activity in the successive cycles.

A new water-insoluble coordination polymer as efficient dye adsorbent and olefin epoxidation catalyst.

A new water-insoluble bi-metallic coordination polymer was simply prepared via polymerization-precipitation of molybdenum complex building blocks with Zn2+ cation. The linker was a di-carboxylic acid consisting of two coordination sites i.e. N,O and COO- suitable for coordinating to MoO2 unit and Zn2+, respectively. Characterization of the prepared coordination polymer was carried out with various physicochemical methods which confirmed the proposed structure. The prepared coordination polymer preferentially adsorbed methylene blue (more than 92% of methylene blue after 2 min) relative to methyl orange and can be reused at least four times without any loss of adsorption efficiency. The adsorption process of both dyes followed the pseudo-second order kinetic equation. Additionally, the obtained coordination polymer catalyzed epoxidation of olefins with tert-butylhydroperoxide (TBHP) quantitatively with excellent selectivity (>99%) under mild reaction conditions.

Four coordinate tin complexes: synthesis, characterization, thermodynamic and theoretical calculations.

In this work, two new Sn(IV) complexes, [SnL(x)]Cl2 where (L(x))(2-) is the deprotonated form of 5-A-salabza-H2=N,N'-bis(salicylidene)-2-aminobenzylamine and A=5-OMe, 5-H, 5-NO2, 5-Br, were synthesized and fully characterized by UV-Vis, FT-IR, (1)H NMR, (13)C NMR, (119)Sn NMR spectroscopies, mass spectrometry and elemental analysis. The thermodynamic formation constants of the complexes were determined spectrophotometrically at 25 °C in acetonitrile. The trend of formation constants of the complexes are as: 5-OMe>5-H>5-NO2>5-Br and Ph2SnCl2>Me2SnCl2>n-Bu2SnCl2. DFT/B3LYP molecular orbital calculations were carried out for the 5-H substituent isomer, [SnL(2)](2+), in an attempt to explain the structure of complexes. The optimized resulting geometries, vibrational frequencies and the NMR resonances of the complexes are discussed.