Pd Ions Research Articles

A novel N-heterocyclic carbene-palladium modified metal–organic framework (Sm-MOF-Pd) for Suzuki-Miyaura cross-coupling reaction

A novel 3D Sm-MOF, namely {n[Sm(L)2·2(H2O)]·(Cl)n, H2L+Cl- = 1,3-bis(4-carboxybenzyl)-imidazolium chloride)}, was prepared under hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction. Then the N-heterocyclic carbene-Pd(II) functionalized metal–organic framework (Sm-MOF-Pd) was yielded by introducing Pd active sites into the Sm-MOF by the post-synthesis modification (PSM) method. This new material was characterized by powder X-ray diffraction (PXRD), thermogravimetric analyses (TGA), scanning electron microscopy (SEM), transmission electron (TEM), energy-dispersive X-ray spectroscopy (EDS), inductively coupled plasma optical emission spectroscopy (ICP-OES) and X-ray photoelectron spectroscopy (XPS) measurements, showing that Pd(II) ions were uniformly dispersed in the Sm-MOF after PSM. The Sm-MOF-Pd reached a catalytic yield of 99 % in Suzuki-Miyaura cross-coupling reactions under optimal reaction conditions. After four cycles, it still maintained high catalytic activity.

Novel palladium(II) and Zinc(II) Schiff base complexes: Synthesis, biophysical studies, and anticancer activity investigation

BackgroundSchiff base metal complexes are considered promising chemotherapeutic agents due to their potential application in cancer therapy. MethodsThe current work sought to synthesize a brand-new Schiff base ligand obtained from 2-hydroxybenzohydrazide and (E)− 1-(2-(p-tolyl)hydrazono)propan-2-one with metal ions which included Pd(II) and Zn(II) ions. Elemental analyses, FT-IR, mass spectra, 1H NMR, UV-Vis spectrometer, and computational analysis characterized the compound's structure. In vitro, the breast cancer cell line (MCF-7) was tested for its sensitivity to Schiff base (HL) and its Pd(II) and Zn(II) complexes. The half-maximal inhibitory concentration IC50 of the compounds was determined and used to perform the comet assay, which was carried out to reveal the photo-induced DNA damaging ability of the compounds of individual cells. Moreover, the compounds' effects on antioxidant defense systems of enzymes in cells: superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities and oxidant Malondialdehyde (MDA) were examined in MCF-7 cells. ResultsThe Pd(II) complex displayed approximately the same IC50 as Cisplatin, while Zn(II) complex had better activity than Cisplatin with very low IC50, 1.40 μg/ml. Significant alterations in SOD, CAT, GPx, and MDA production were discovered, inducing oxidative stress, enlarging ROS production, and reducing the antioxidant amount. This change was approximately similar in most compounds. Consequently, it promoted apoptosis, particularly the Zn(II) complex, which demonstrated an improved impact because of its ability to influence the antioxidant defense systems of enzymes, mostly SOD and GPx, besides increasing MDA levels. ConclusionIt can be concluded that Zn(II) complex is the most effective anticancer drug since it induced a very similar genotoxic effect as Cisplatin and has a very low IC50 value.

A novel nanomagnetic palladium (II) complex of bisimidazolium-based N[sbnd]heterocyclic carbene; An efficient heterogeneous catalyst for A3 coupling reactions

Herein, a novel nanomagnetic NHC-Palladium complex was successfully prepared applying post-synthetic modification (PSM) condensation between Fe3O4-support imidazole and a synthetic bisamide moiety, carrying the alkyl halide functionalities at the end of its chain, followed by chelation of Pd ions to generate the corresponding complex. The [Fe3O4@bisimidazolium-Pd]2Cl− complex gave the best catalytic performance in synthesizing propargylamines through A3 coupling of various substituted aromatic and cycloaliphatic aldehydes and secondary amines with aromatic and liner alkynes in PEG-400. Primary amines are inefficient to produce unknown byproducts; whereas, secondary amines react quickly. Significantly, alkynes having a high electron density reduce the conversion rate. Moreover, aromatic and aliphatic aldehydes are active, but the electron-drawing substituent on benzaldehyde decreases the rate of conversion. Furthermore, the [Fe3O4@bisimidazolium-Pd]2Cl− catalyst can be reused seven times without metal leaching or losing its ability, which shows how stable it is when used in a reaction.

Palladium Enhanced Iron Active Site - An Efficient Dual-Atom Catalyst for Oxygen Electroreduction.

Metal-nitrogen-carbon (M-C/N) electrocatalysts have been shown to have satisfactory catalytic activity and long-term durability for the oxygen reduction reaction (ORR). Here, a strategy to prepare a new electrocatalyst (Fe&Pd-C/N) using a unique metal-containing ionic liquid (IL) is exploited, in which Fe & Pd ions are positively charged species atomically dispersed by coordination to the N of the N-doped C substrate, C/N. X-ray absorption fine structure, XPS and aberration-corrected transmission electron microscopy results verified a well-defined dual-atom configuration comprising Fe+2.x -N4 coupled Pd2+ -N4 sites and well-defined spatial distribution. Electronic control of a coupled Fe-Pd structure produces an electrocatalyst that exhibits superior performance with enhanced activity and durability for the ORR compared to that of commercial Pt/C (20%, Johnson Matthey) in both alkaline and acid media. Density functional theory calculations indicate that Pd atom can enhance the catalytic activity of the Fe active sites adjacent to Pd sites by changing the electronic orbital structure and Bader charge of the Fe centers. The excellent catalytic performance of the Fe&Pd-C/N electrocatalyst is demonstrated in zinc-air batteries and hydrogen-air fuel cells.

Efficient Removal and Preconcentration of Pd(II) Ions in Environmental Water Using Co2SiO4 Nanoparticles Modified by Mordant Red 3 as a Novel Adsorbent

Efficient Removal and Preconcentration of Pd(II) Ions in Environmental Water Using Co2SiO4 Nanoparticles Modified by Mordant Red 3 as a Novel Adsorbent

Recovery of Pd(II) Ions from Aqueous Solutions Using Activated Carbon Obtained in a Single-Stage Synthesis from Cherry Seeds

This paper describes a single-stage synthesis process for activated carbon using cherry seeds. The influences of the carbonization temperature and the time were investigated. Using the BET method, the surface area of the obtained activated carbons was determined, as well as the pore distribution, while SEM images provided further insight into the structure of the surface. Next, the adsorption isotherm was derived. For the test, Pd(II) chloride complex ions were used. It was found that the obtained activated carbon were suitable for palladium(II) recovery from diluted aqueous solutions. Out of the tested parameters of carbon synthesis, the most optimal one was found to be 500 °C for 3 h. Additionally, it was confirmed that the increase in the adsorption temperature affects the increase in palladium load from 1.6 mg/g at 20 °C to 15.6 mg/g at 50 °C (for the best-performing sample). This fact may suggest that the process of adsorption is associated with chemical reactions.

Highly effective recovery of palladium from a spent catalyst by an acid- and oxidation-resistant electrospun fibers as a sorbent

Palladium is not only a precious metal but also is widely used in catalyst production, therefore it is of significance to recover palladium from spent catalysts. In this paper, Nanofiber modified by 2-Thionicotinic acid (TN-Nanofiber) featuring acid- and oxidation-resistant was fabricated through electrospinning and chemical grafting, which can trap efficiently Pd(II) ions from the extremely acidic and oxidizing systems derived from the leaching of spent catalyst. The adsorption kinetic data of Pd(II) ions was well described by the pseudo-second-order model, and the times required to reach equilibrium was 60 min. The Langmuir isotherm model provided better fitting for the Pd(II) ions adsorption, and the maximum uptake capacity of TN-Nanofiber was evaluated as 348.4 mg/g for Pd(II) ions. Furthermore, the column adsorption experiments proved the feasibility of TN-Nanofiber separation of Pd(II) ions from the spent catalyst. Investigation of the adsorption mechanism demonstrated a planar quadrilateral coordination pattern between the Pd(II) ions and the adsorption sites of TN-Nanofiber, which includes one N and one S atom sourced from the adsorption sites and two Cl atoms derived from the original PdCl42−. In summary, TN-Nanofiber may serve as the next generation of emerging adsorbents to recover palladium from the strongly acidic and oxidizing systems due to its excellent performance.

A highly efficient and selective fluorescent probe for Pd (II) based on benzotriazole-coumarin derivative and its catalytic application in Sonogashira reaction

Palladium-catalyzed coupling reactions have become effective tools for forming new carbon–carbon bonds. In this work, a novel fluorescence active benzotriazole-coumarin derivative, (E)-N'-((1H-benzo[d][1,2,3]triazol-6-yl)methylene)-7-(diethylamino)-2-ox o-2H-chromene-3-carbohydrazide (BTANC), was synthesized as ligand in Pd(II) cation coordination. It is shown that BTANC has a strong fluorescent emission at 483 nm and Pd(II) can effectively quench the fluorescence of BTANC and BTANC shows excellent sensitivity and selectivity towards Pd (II) ions. Otherwise, the BTANC-Pd(II) complex was also tested in the Sonogashira coupling reaction of phenylacetylene and aryl halides. The desired product was obtained with high yield (up to 99%) under the optimized reaction conditions. More to that, Low fluorescence emission was observed during the Pd-catalyzed reaction process and the fluorescent emission of BTANC was recovered at the end of the Pd-catalyzed reaction because the oxidative addition of the aryl halide towards Pd (0) was shut down at the end of the Pd-catalyzed reaction. This fluorescence properties of BTANC indicates the feasibility of using fluorescence signal as a potential tool to monitor the completion of the Sonogashira coupling reaction.

Ethylenediamine functionalized waste polyethylene terephthalate-derived metal-organic framework for adsorption of palladium ions from aqueous solutions

The recovery of palladium metal is essential in order to meet its growing global demand and also to address water pollution crisis. Herein, MIL-101(Cr)/ED was fabricated from waste polyethylene terephthalate (PET) bottles and modified using ethylenediamine (ED) to retrieve divalent palladium (Pd(II)) metal ions from aqueous environment. The successful grafting of ED moieties onto MIL-101(Cr) was established by the appearance of broad bands at around 2800–3300 cm−1 on the Fourier transform infrared spectrum which was supported by the increase in binding energy using density functional theory. The adsorption experiments revealed that higher Pd(II) ion intake occurred using 30 mg of MIL-101(Cr)/ED in acidic media of pH = 3.0. The data fit better on the Langmuir isotherm with the correlation coefficient (R2) 0.9089. At 25 °C, the MIL-101(Cr)/ED achieved a substantial enhancement in the intake capacities of 454.2 mg.g−1. Kinetics data demonstrated to comply with pseudo-second order, achieving a rapid rate of Pd(II) adsorption by the MIL-101(Cr)/ED in less than 3 min given by the rate constant k2 = 0.02065 g.mg−1.min−1. The MIL-101(Cr)/ED has high affinity for Pd(II) ions as more than 80% removal was achieved even in presence of other ions. These observations revealed the potential utilization of MIL-101(Cr)/ED as an adsorbent to efficiently extract Pd(II) ions from wastewater.

Preparation, Characterization, Antioxidant and Antibacterial Studies of New Metal (II) Complexes with Schiff Base for 3-amino-1-phenyl-2- pyrazoline-5-one

A new ligand complexes have been synthesis from reaction of metal ions of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II), Pd(II) and Pt(II) with schiff base LH. 5-[(2-Hydroxy-naphthalen-1-ylmethylene)-amino]-2-phenyl-2,4-dihydro-pyrazol-3-one, this ligand was characterized by Fourier transform infrared (FTIR), UV-vis, 1H, 13CNMR, and mass spectra. All complexes were characterized by techniques micro analysis C.H.N, UV-vis and FTIR spectral studies, atomic absorption, chloride content, molar conductivity measurements and magnetic susceptibility. The ligand acts as bidentate, coordination through nitrogen atom from azomethin group and deprotonated phenolic oxygen atom. The spectroscopic and analytical measurements showed that the geometric shape of the prepared complexes is octahedral, while the square planar of the palladium and platinum complexes. The ligand and its complexes were having been screened for their antimicrobial activities and antioxidant

Front Cover: Chiral Self‐Sorting in Pd6L12 Metal‐Organic Cages (Chem. Asian J. 8/2023)

The origin of chiral self-sorting in the building blocks of life remains a fundamental question. Chiral self-sorting in the formation of supramolecular cages expands our understanding of the phenomenon in general. It controls the choice of the selective chiral isomer against numerous possible mixtures. This work reports chiral social self-sorting in the diastereoselective self-assembly of Pd6L12 metal-organic cages with a racemic mixture of axially chiral bis-pyridyl ligand with Pd(II) ions. More information can be found in the Research Article by Ramalingam Natarajan et al.

Synthesis and structural characterization of palladium pincer complexes: Sustainable synthesis of benzothiazoles

An efficient Pd(II)N^N^S pincer type catalysts‐promoted sustainable construction of pharmaceutically important benzothiazole derivatives from primary alcohols and 2‐aminothiophenol via acceptorless dehydrogenative coupling (ADC) method has been described. The newly synthesized ligand L2 and the Pd(II) complexes in addition to L1 and L3 were characterized by analytical and Fourier transform infrared spectroscopy (FT‐IR), UV–visible (UV–vis), and nuclear magnetic resonance (NMR) spectral techniques. Further, the ORTEP views of the complexes 2 and 3 were established by a single crystal XRD study, which evidenced the coordination of the thiosemicarbazone ligands and disclose the square‐planar geometry around the Pd(II) ion. The present homogeneous catalytic system involves synthesizing a range of benzothiazoles via C−S and C−N bond formation with excellent yields up to 93%. The described methodology employs a sustainable, highly abundant, and inexpensive alcohol as starting material using 1 mol% catalyst loading, and water and hydrogen gas are the only by‐products. Furthermore, a plausible mechanism involving in situ aldehyde formation via dehydrogenation of primary alcohols has been proposed. A large‐scale synthesis of 2‐(4‐methoxyphenyl)benzo[d]thiazole illustrates the synthetic utility of the present catalytic protocol.

Dynamic Monitoring of the Structural Evolution of Au@Pd under Electrochemistry

Core–shell nanocatalysts have shown superior catalytic activity than monometallic catalysts. However, these metastable materials are susceptible to structural changes during catalysis. Comprehending the evolution of surface sites and their stability under different reaction conditions is crucial for designing durable and highly active core–shell nanocatalysts. Herein, structural transformation of the atomic layer thickness of Pd shells on Au nanocubes in different electrolytes at various electrochemical windows was investigated by a combination of cyclic voltammetry (CV), surface-enhanced Raman spectroscopy (SERS) of adsorbed probe molecules, and elemental analysis. Pd sites are stable under basic and neutral conditions but experience severe structure evolution under acidic conditions. Pd atoms that are directly coordinated by Au atoms, upon oxidation at evaluated potential, transform into Pd ions via the reaction with H+ which would also be adsorbed on the Au sites. These Pd ions are easily coreduced with the formed Au ions into surface alloys in the backward CV scan. In contrast, Pd atoms in the thick Pd overlayer (>1 monolayer) are likely to dissolute into the electrolyte solution and leach. SERS revealed that the change of Pd sites primarily occurred at contiguous Pd sites and isolated Pd sites were relatively stable. This evolution mechanism provides new insight into the rational design of efficient and stable catalysts and is expected to promote further application of core–shell nanocatalysts.

Cd(II) and Pd(II) Mixed Ligand Complexes of Dithiocarbamate and Tertiary Phosphine Ligands-Spectroscopic, Anti-Microbial, and Computational Studies.

Mixed ligand complexes of Pd(II) and Cd(II) with N-picolyl-amine dithiocarbamate (PAC-dtc) as primary ligand and tertiary phosphine ligand as secondary ligands have been synthesized and characterized via elemental analysis, molar conductance, NMR (1H and 31P), and IR techniques. The PAC-dtc ligand displayed in a monodentate fashion via sulfur atom whereas diphosphine ligands coordinated as a bidentate mode to afford a square planner around the Pd(II) ion or tetrahedral around the Cd(II) ion. Except for complexes [Cd(PAC-dtc)2(dppe)] and [Cd(PAC-dtc)2(PPh3)2], the prepared complexes showed significant antimicrobial activity when evaluated against Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger. Moreover, DFT calculations were performed to investigate three complexes {[Pd(PAC-dtc)2(dppe)](1), [Cd(PAC-dtc)2(dppe)](2), [Cd(PAC-dtc)2(PPh3)2](7)}, and their quantum parameters were evaluated using the Gaussian 09 program at the B3LYP/Lanl2dz theoretical level. The optimized structures of the three complexes were square planar and tetrahedral geometry. The calculated bond lengths and bond angles showed a slightly distorted tetrahedral geometry for [Cd(PAC-dtc)2(dppe)](2) compared to [Cd(PAC-dtc)2(PPh3)2](7) due to the ring constrain in the dppe ligand. Moreover, the [Pd(PAC-dtc)2(dppe)](1) complex showed higher stability compared to Cd(2) and Cd(7) complexes which can be attributed to the higher back-donation of Pd(1) complex.

Chiral Self-Sorting in Pd6 L12 Metal-Organic Cages.

Chiral self-sorting during the formation of cage-like molecules continues to fascinate and advance our understanding of the phenomenon in general. Herein, we report the chiral self-sorting in the Pd6 L12 -type metal-organic cages. When a racemic mixture of axially chiral bis-pyridyl ligands undergo coordination-driven self-assembly with Pd(II) ions to form Pd6 L12 -type cages, the system has the option of chiral self-sorting to afford any of at least 70 pairs of (one homochiral and 69 heterochiral) enantiomers and 5 meso isomers or a statistical mixture of everything. However, the system resulted in diastereoselective self-assembly through a high-fidelity chiral social self-sorting to form a racemic mixture of D3 symmetric heterochiral [Pd6 (L6R/6S )12 ]12+ /[Pd6 (L6S/6R )12 ]12+ cages.

SYNTHESIS AND INVESTIGATING OF THE NOVEL OF ES-PANI@PDNPSNANOCOMPOSITE

The aim of this research is the synthesize materials Novel of ES-PANI@PdNPs nanocomposites obtained chemically. The synthesis of ES-PANI@PdNPs nanocomposite was prepared by the chemical method using FeCl3 as a redox initiator (insitu) and refluxed for 48 hours at 500C, then dried at 500C for 24 hours, obtained a brown-black solid and no water-soluble.The nanocomposite is characterized by UV-Vis and Fourier transform infrared (FTIR) spectroscopy, the composite shows absorption of Pd(0) nanoparticles along with ES-PANI peaks at 312 nm. FTIR and UV-visible spectra show an interaction between Pd(0) and ES-PANI. This indicated that Pd(0) zero valence had been formed and that internal reduction processes had occurred by imines and amines toward Pd(II) ions.

An efficient and durable bifunctional electrocatalyst based on PdO and Co2FeO4 for HER and OER

The adoption of effective, minimal, and versatile electrocatalysts for water splitting to generate hydrogen fuels is of critical importance. The bulk of newly described materials have considerable onset potential, but their electrocatalytic activity is limited by weak electrical conductivity and a limited range of catalytic sites. The combination of a few precious metals added with transition metal-based compounds is a novel and captivating approach. Herein, cobalt ferrite oxide (Co2FeO4) @ palladium oxide (PdO) nanostructures have been prepared through the combined use of hydrothermal and ultraviolet (UV) irradiation techniques. For hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) kinetics, the modified composition offers a high concentration of active sites, improved electrical conductivity, and stability. The Co, Fe, and Pd ions at the composite system's interface may affect the adsorption energy of reaction intermediates synergistically, enabling the process to continue with less potential. The electrocatalyst Co2FeO4@PdO demonstrates an excellent bifunctional approach to electrochemical water splitting (EWS) for HER and OER in alkaline medium. As-prepared electrocatalyst shows an overpotential value of 269 and 259 mV for HER and OER at 10 and 20 mA/cm2 current densities respectively. The low charge transfer resistance values such as 72.2 and 62.4 Ω and durability for 48 h has been observed toward HER and OER, support this material as an efficient and durable electrocatalyst for energy conversion systems.

Identification of genes responsible for absorbing palladium ion in Escherichia coli.

The capability of Escherichia coli BW25113 to adsorb palladium (Pd) ions in a single-gene-knockout library was investigated using high-throughput screening. The results revealed that compared to BW25113, nine strains promoted Pd ion adsorption, whereas 22 strains repressed. Although further studies are required because of the first screening results, our results will provide a new perspective for improving the biosorption.

Post-synthetic modification of dual-porous UMCM-1-NH2 with palladacycle complex as an effective heterogeneous catalyst in Suzuki and Heck coupling reactions

Herein, the synthesis of a novel functionalized metal-organic-framework (MOF) UMCM-1-NH2-furfural/Pd Nano composite [UMCM-1-NH2-F2C-Pd Nano composite] is reported using the post-synthetic modification of UMCM-1-NH2. The targeted complex was prepared while chemically attaching the furfural – using Schiff base reaction followed by complexation with Pd ions. Afterward, the synthesized solid was applied as a very effective multifunctional catalyst in Suzuki and Heck coupling reactions. This technique which was facile, clean, and economically justified used only 0.01 g of the catalyst during the reaction. The easy setup, nontoxic solvent, enhanced yield, short reaction times, high turnover frequency, and catalyst durability are among the marked benefits of this synthesis method. Overall, the high catalytic activity of UMCM-1-NH2-F2C-Pd Nano composite may be due to the obtained high surface area and the synergistic features created between Lewis acidic Zn nodes and Pd ions.

Electrocatalytic Performance of Ethanol Oxidation on Ni and Ni/Pd Surface-Decorated Porous Structures Obtained by Molten Salts Deposition/Dissolution of Al-Ni Alloys.

Ni coatings with high catalytic efficiency were synthesised in this work, obtained by increasing the active surface and modifying Pd as a noble metal. Porous Ni foam electrodes were obtained by electrodeposition of Al on a nickel substrate. Deposition of Al was carried out with potential -1.9 V for a time of 60 min in NaCl-KCl-3.5 mol%AlF3 molten salt mixture at 900 °C, which is connected with the formation of the Al-Ni phase in the solid state. Dissolution of Al and Al-Ni phases was performed by application of the potential -0.5 V, which provided the porous layer formation. The obtained porous material was compared to flat Ni plates in terms of electrocatalytic properties for ethanol oxidation in alkaline solutions. Cyclic voltammetry measurements in the non-Faradaic region revealed the improvement in morphology development for Ni foams, with an active surface area 5.5-times more developed than flat Ni electrodes. The catalytic activity was improved by the galvanic displacement process of Pd(II) ions from dilute chloride solutions (1 mM) at different times. In cyclic voltammetry scans, the highest catalytic activity was registered for porous Ni/Pd decorated at 60 min, where the maximum oxidation peak for 1 M ethanol achieved +393 mA cm-2 compared to the porous unmodified Ni electrode at +152 mA cm-2 and flat Ni at +55 mA cm-2. Chronoamperometric measurements in ethanol oxidation showed that porous electrodes were characterised by higher catalytic activity than flat electrodes. In addition, applying a thin layer of precious metal on the surface of nickel increased the recorded anode current density associated with the electrochemical oxidation process. The highest activity was recorded for porous coatings after modification in a solution containing palladium ions, obtaining a current density value of about 55 mA cm-2, and for a flat unmodified electrode, only 5 mA cm-2 after 1800 s.