Inorganic Chemistry Research
Volume:5 Issue: 1, Jun 2021

The catalytic activity of bimetallic MOFs known as STA-12(M1, M2)(M1,2= Mn, Fe, Co) was investigated in the oxidation of benzylic alcohols to corresponding aldehydes at ambient conditions. The oxidation reaction with Na2S2O4/TBHP (tert-Butyl hydroperoxide) mixture shows total selectivity and excellent efficiency under desired reaction times. The heterogeneous catalyst displays high reusability and stability for the ten consecutive reactions without decreasing in yield and selectivity. To identify radical species responsible for the oxidation process, selective radical scavenging experiments were performed and a purposed oxidation mechanism was discussed.

A new 1D copper(I) coordination polymer [Cu2(μ-L)(μ-I)2]n (1), where L is N,N'-bis(4-nitrobenzylidene)butane-1,4-diamine, was synthesized and characterized by CHN, FT-IR, 1H NMR, and single-crystal X-ray analyses. Based on X-ray results, this new compound crystallizes in a monoclinic system with space group P21/c. The asymmetric unit consists of one copper and one iodine atoms and half of the Schiff base ligand (L). The flexible Schiff base compound is coordinated to copper(I) ion as a bis-monodentate ligand. The coordination geometry around the copper(I) ions is distorted trigonal planar. The thermal behavior of 1 was studied using thermogravimetry analysis. Moreover, the nanoparticles of 1 were prepared via the ultrasonic-assisted method and characterized by XRD and SEM analyses.

The magnetic nanocomposites [magnetite@silica@titania@metallo tetra hydroxyl phenyl porphyrin, Fe3O4@SiO2@TiO2@MTHPP] (MSiTMP; M = CoIII, ZnII, NiII) and [Fe3O4@SiO2@TiO2] (MSiT) have been synthesized and characterized. These nanocomposites were used to degrade of methylene blue (MB) under the blue light-emitting diode (LED) lamp irradiation. The degradation of MB was monitored by UV-Vis spectrometry. Upon a 180 min irradiation period maximum degradation of MB in presence of MSiTNiIIP, MSiTZnIIP, MSiTCoIIIP and MSiT photocatalysts were 90, 80, 63, and 48 %g−1, respectively. After three 180 min runs, the photocatalysts still exhibited good activity. From Ultra-Violent-Diffuse reflectance spectroscopy spectra, the band gap energies of the photocatalysts were found to be 2.6, 2.5, 2.4 and 2.2 eV for MSiT, MSiTCoIIIP, MSiTZnIIP and MSiTNiIIP, respectively. The results consist with the observed relative photocatalytic activity of the photocatalysts which is as follows: MSiTNiIIP> MSiTZnIIP >MSiTCoIIIP >MSiT. The higher photocatalytic properties of MSiTNiIIP photocatalyst may be due to the fact that NiII complex is more susceptible to receive electron and reach to steady state than that of ZnII and CoIII. The degradation of MB using these nanocomposites were found to follow the pseudo first order kinetics.

In this paper, we examined the morphology, shape and magnetic and electronic properties of Selenium-doped nickel oxide nanoparticles (Se-doped NiO-NPs), which were achieved through a sol-gel technique that involved the usage of Cydonia oblonga plant extract. The structural and magnetic properties of Se-doped NiO-NPs were evaluated by the employment of XRD, FESEM / EDAX, FT-IR, UV-Vis, and VSM procedures. According to XRD studies, the nanoparticles accommodated a face-centered cubic (fcc) crystalline structure and a space group of (Fm3m). In addition, the size of nanoparticles in optimal conditions (the optimum temperature of 400 °C and 3% Se-doped) were reported to be 7.7 nm while a direct relationship was also observed with increasing the concentration of selenium. The FESEM images confirmed the spherical morphology of Se-doped NiO-NPs. Also, the photocatalytic properties of Se-doped NiO-NPs were evaluated through the usage of methylene blue (MB) pigment degradation under UV light. The outcomes of this evaluation exhibited more than 76 % of degrading within 200 min. To complete the project, the cytotoxicity aspect was also investigated on L929 cell lines, requiring the application of MTT assay, while the results were indicative of toxicity effects that can be used for inhibiting cancer cells.

The effect of synthesis procedure on formation of [Ag2(μ2-py-4-c)2]n (1) and {[Ag(py-4-c)(Hpy-4-c)]1/2.[Ag(py-4-c)]}n (2) coordination polymers (py-4-c = pyridine-4-carboxylate) were studied. Pyridine-4-carboxylic acid (Hpy-4-c) was deprotonated by KOH and the anionic ligand was become available for interaction with the metal ion. AgNO3 was added to the ligand solution with two different rates in two conditions of bulk and ultrasonic bath which yielded to [Ag2(μ2-py-4-c)2]n (1) on stirrer and a different coordination polymer in ultrasonic bath, {[Ag(py-4-c)(Hpy-4-c)]1/2.[Ag(py-4-c)]}n (2). Formation of [Ag2(μ2-py-4-c)2]n (1) and {[Ag(py-4-c)(Hpy-4-c)]1/2.[Ag(py-4-c)]}n (2) were investigated with different analyses such as Powder X-ray Diffraction (PXRD), Fourier-Transform Infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) and Thermogravimetric analysis (TGA). Moreover, antibacterial activity of the samples was investigated against both gram-negative (E. coli) and gram-positive (S. aureus) bacteria’s.

Two novel heterocyclic Schiff base complexes ([VOL1(DMF)] [H2L1 = (E)-1-((2-amino-5-nitrophenyl)imino-methyl) naphthalen-2-ol] and [VO2L2] [H2L2 = [(E)-1-((2-aminoethyl) imino-methyl)naphthalen-2-ol]) were synthesized and FT-IR, elemental analysis and UV-Vis spectroscopy were used to fully characterize them. Single-crystal X-ray diffraction was used to determine the structure of the [VO2L2] complex, in which the coordination around the vanadium ion is best described as distorted square pyramidal. The basal plane is formed by the donor atoms (NNO) of the Schiff base ligand and one of the oxo groups while the apical position is occupied by the other oxo group in the structure. The Schiff base complexes were loaded over TiO2 photocatalyst and calcined at 450°C. The MOX/TiO2 structure and morphology were characterized by FT-IR, scanning electron microscopy (SEM), X-ray diffraction (XRD), EDX and solid state UV-Vis absorption. Photocatalytic oxidation of methyl orange (MO) and methylene blue (MB) dyes in aqueous media by solar and visible lights was used to evaluate the photocatalytic efficiency of MOX/TiO2 semi-conducting nanoparticles. The incorporation of these complexes enhanced TiO2 activation with visible light compared with naked TiO2, according to the results.

Palladium has been supported on 2-((3-(piperazin-1-yl) propylimino)methyl)phenol functionalized magnetite nanoparticles (denoted as Fe3O4@SiO2@L-Pd(II)). The supported Pd was used as an active heterogeneous catalyst in Suzuki cross-coupling reaction under solvent-free conditions. This nanocatalyst could be facilely separated via magnetic concentration and the isolated catalyst exhibited long-term stability. Easy work-up, high yield, recycling of the catalyst, low reaction times, non-toxicity of catalyst and and solvent-free conditions as an environmentally benign procedure are the main merits of this protocol.The produced catalyst were characterized by XRD, FT-IR, XPS, SEM, TEM, EDAX, VSM, TGA and ICP-OES.

In this research, the characterization of complexes [Pd(aemptrz)Cl2] (1), [Pd2(μ-mptrz)2(mptrz)2(en)].CH3OH (2) [Pd2(μ-mptrz)4] (3) and [Pd2(μ-mptrz)2(mptrz)2(en)] (4) (where aemptrz is 1‐(1‐(λ2‐azanyl)ethyl)‐4‐methyl‐5‐(λ1‐sulfanyl)‐4H‐1λ4,2,4‐triazole, en is ethylene diamine and Hmptrz is 4-methyl-4H-1,2,4-triazole-3-thiol) were carried out by Density Functional Theory (DFT) calculations. Structural, electronics and molecular properties (such as bond distances, bond angles, energies of highest occupied molecular orbital (EHOMO), the lowest unoccupied molecular orbital (ELUMO), the energy gap (ΔE), chemical hardness η, the dipole moment μ and Natural bond orbital (NBO) analysis of compounds) have been investigated using B3LYP/TZVP level of theory. Moreover, electronic structures of all complexes via NBO calculation show that Pd-N and Pd-S bonds are made of delocalization of occupancies from lone pair (LP) orbital of N, S atoms to the palladium atom. The FT-IR spectroscopy analysis and electronic spectra were calculated using B3LYP/TZVP basis set and compared with the experimental values. Furthermore calculation of vibrational spectra are also allocated based on the potential energy distribution (PED) using the VEDA 4 program. The electronic spectra were calculated using DFT and time dependent density functional theory (TD-DFT) methods.

The utilization of NH3BH3 (ammonium borane) as a H2 gas storage compound is restricted by its slow rate for H2 evolution. In this study, three Ag@Zn-MOF nanocomposites with different amounts of Ag:Zn-MOF ratio of 0.25:1 (1), 0.5:1 (2), and 1:1 (3) were investigated as catalysts for hydrogen evolution from hydrolysis of NH3BH3. Well dispersed encapsulated Ag nanoparticles (30-60 nm) in the matrix of the composites have been prepared in the presence of Zn(II) metal-organic frameworks (Zn-MOFs) in an aqueous solution by using NaBH4 as a reducing agent at room temperature. These nanocomposites have shown good catalytic activity for the hydrolysis of NH3BH3.

Using Se8 selenium and cyclic peptides and nanoparticles (SeCPNP), six configurations for the adsorption of the 5-fluorouracil (FU) anticancer drug on SeCPNP have been examined (SeCPNP/FU1-6). Binding energies, solvation energies and quantum molecular descriptors such as electrophilicity (ω) and global hardness (η) in the aqueous solution and gas phase were studied at the density functional level of M06-2X. The most stable structure by binding energy calculations was determined. The values obtained from solvation energies indicate that SeCPNPs can increase the solubility of FU, which is a key factor in drug delivery. According to quantum molecular descriptors, the reactivity of cyclic peptide (CP) and FU drug in all structures (SeCPNP / FU 1-6) increases. AIM calculations for all structures show that Se-A interactions (A = O, H, N, F, C) and intermolecular hydrogen bonding play an important role for this drug delivery system. In structures where FU is parallel to SeCPNP and undergoes interactions concurrently with Se8 and CP, it is more stable than structures in which the drug undergoes interactions only with Se8 and CP.

Two copper (II) complexes of Quercetin (Q) with metal:ligand stoichiometry ratios of 1:1 and 1:2 were synthesized. The synthesized complexes structures were determined by UV-Vis spectroscopy, Infra-red spectroscopy, thermogravimetry, elemental analyses as well as cyclic voltammetry. The spectroscopic data suggest that the chelation between Q and Copper (II) can occur through a 3-hydroxy-4-carbonyl site. The antioxidant effectiveness and scavenging activity of quercetin and its complexes were evaluated using DPPH method and luminol-hydrogen peroxide chemiluminescence system. The results showed that prepared compounds have strong quenching effects on the chemiluminescence intensity of luminol in the alkaline medium and are efficient in scavenging free radicals produced in this system. Reaction system variables such as luminol, quercetin and their complexes' concentration and various pH of luminol solution were investigated. Stren-Volmer equation was also used to study the kinetics of the luminol reaction system and linear relationship was obtained between CL intensity and the concentration of these compounds in a range of 10-100 mg/L. The Stern–Volmer quenching constant, Kq value in the presence of free quercetin is higher than the complexes, which indicates the fact that complexation with metal ions changes the chemical properties of quercetin and decreases the inhibitory ability and radical scavenging efficiency. The concentration-dependent inhibitory ability of quercetin and copper complexes is attributable to the presence of several hydroxyl groups in their structure that react with superoxide or peroxyl radicals available in luminol-H2O2 system. Our study strongly confirmed the potent radical scavenging property of polyphenolic compounds and their metal complexes.

In this study, mesoporous zirconium phosphates (m-ZrPs) with a different molar ratio of phosphate to zirconium were synthesized and used as the heterogeneous catalyst for the production of n-butyl levulinate from levulinic acid. The catalysts were characterized using various techniques such as N2 adsorption-desorption, XRD, FT-IR, ICP-OES, SEM, and TEM. The prepared catalysts were confirmed to possess the mesoporous structure with a high surface area. Among the synthesized catalysts, m-ZrP-2 showed the best performance in the conversion of levulinic acid to n-butyl levulinate. The reaction conditions were optimized on parameters such as reaction time, temperature, amount of catalyst, and the molar ratio of LA to n-butanol. Temperature 120 °C, reaction time 7 hours, the ratio of acid to alcohol 1:9, and 0.01g catalyst were selected as the optimum conditions. In addition, the selected m-ZrP-2 catalyst was successfully recycled for six consecutive cycles without significant loss in its activity.