Palladium Ions Research Articles

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.

Adsorptive of vanadium and palladium ions using chitin-extracted from shrimp shell wastes: genetic programming modeling

In this study, chitin was extracted from shrimp shells (SS) and characterized by scanning electron microscopy, X-ray diffraction, and Fourier transforms infrared spectroscopy. And investigate the adsorption of vanadium (V) and palladium (Pd) toxic metals onto the chitin. The effect of parameters such as the concentration of V and Pd, contact time, solution pH, adsorbent dose, cations, and anions were studied on the adsorption process. Kinetic, isotherm, and thermodynamic models were investigated. Genetic programming (GP) is used to obtain an appropriate equation showing the relationship between the variables. Experimental optimum conditions were found in the V and Pd concentrations of 25 mg/L, pH of 9, an adsorbent dose of 0.8 g/L and a contact time of 15 minutes. The maximum adsorption capacities (q m) of 13.15 and 12.65 mg/g were obtained for V and Pd, respectively. Among the anions and cations examined in this study, Ca2+ and SO4 2- had the greatest effect on the absorption of V and Pd on chitin. The adsorption kinetics followed a pseudo-second-order kinetic model and the equilibrium data showed a good fit of the Langmuir model and demonstrated a monolayer and favorable physisorption process. The thermodynamic analysis depicted that the process of adsorbing V and Pd using chitin was endothermic and spontaneous. Findings also presented GP as a potential tool for identifying the behavior of V and Pd adsorption. It can be concluded that chitin extracted from SS wastes, as a nontoxic and cheap adsorbent, could efficiently remove V and Pd from aqueous solutions.

Synthesis of sulfur-chlorine-doped fluorescent carbon quantum dots from leachate membrane concentrate as a selective probe for Pd2+ detection

In this work, humic acid-based sulfur-chlorine-doped carbon quantum dots (L-CQDs) were synthesized by using a polyethylene glycol (PEG)-assisted hydrothermal technique using landfill leachate concentrate (LLC) as a carbon source. The prepared L-CQDs contain many oxygen-containing functional groups on the surface with a small average particle size of 4–6 nm, resulting in excellent hydrophilicity and dispensability. The three-dimensional fluorescence spectrum shows that the characteristic peak for humic acid for LLC is redshifted after adding PEG as an inactivator, indicating that L-CQDs are synthesized by PEG encapsulation and linkage. The optimum condition for preparing L-CQDs involves the addition of 0.5 g PEG (MW = 2000) into 20 mL LLC and reaction at 200 °C for 5 h, with the optimal L-CQD quantum yield reaching 5.32%. L-CQDs were used to prepare fluorescent nanoprobes for the detection of palladium ions (Pd2+). The obtained nanoprobe shows admirable performance in detecting Pd2+, with high selectivity, excellent water solubility and stability. The fluorescence intensity of the nanoprobe is selectively quenched through static quenching by Pd2+ in the concentration range of 5–40 μmol L−1. This work provides a simple, easy, and fast detection method for Pd2+ and opens up a way for the resource utilization of LLC.

The Effect of Polymer Matrix on the Catalytic Properties of Supported Palladium Catalysts in the Hydrogenation of Alkynols

Palladium catalysts were obtained by the adsorption method involving the sequential deposition of polyvinylpyrrolidone (PVP) and then palladium ions on a modified zinc oxide surface without high-temperature calcination and reduction stages. The immobilized PVP-palladium catalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET), infrared spectroscopy (IRS), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and elemental analysis methods. It was found that the introduction of polymer into the catalyst’s composition promotes the dispersion and uniform distribution of active phase nanoparticles (PdO, Pd0) on the surface of zinc oxide. The catalysts were tested in the hydrogenation of complex acetylene alcohol, 3,7,11-trimethyldodecyn-1-ol-3 (C15-yn) under mild conditions (0.1 MPa, 40 °C). For comparison, studies on stereoselective hydrogenation of the short-chain alcohol 2-hexynol-1 were performed. It was shown that modification of the catalyst with polymer improves its catalytic properties. High C15-alkenol selectivity (98%), activity (W = 70 × 10−6 mol/s), and stability (turnover number (TON) 62,000) were achieved on a Pd-PVP/ZnO catalyst. Varying the active phase made it possible to reduce the metal content without deteriorating the catalytic performance of the catalyst.

Synthesis, characterization and anticancer properties: A series of highly selective palladium(II) substituted-terpyridine complexes

Ten new palladium(II) complexes [PdCl(L1−10)]Cl have been synthesized by the reaction of palladium(II) chloride and ten 4′-(substituted-phenyl)-2,2′:6′,2′′-terpyridine ligands bearing hydrogen(L1), p-hydroxyl(L2), m-hydroxyl (L3), o-hydroxyl (L4), methyl (L5), phenyl (L6), fluoro (L7), chloro (L8), bromo (L9), or iodo (L10). Their structures were confirmed by FT-IR, 1H NMR, elemental analysis and/or single crystal X-ray diffraction analysis. Their in vitro anticancer activities were investigated based on five cell lines, including four cancer cell lines (A549, Eca-109, Bel-7402, MCF-7) and one normal cell line (HL-7702). The results show that these complexes possess a strong killing effect on the cancer cells but a weak proliferative inhibition on the normal cells, implying their high inhibitory selectivity for the proliferation of the cancer cell lines. Flow cytometry characterization reveals that these complexes affect cell proliferation mainly in the G0/G1 phase and induce the late apoptotic of the cells. The quantity of palladium(II) ion in extracted DNA was determined by ICP-MS, which proved that these complexes target genomic DNA. And the strong affinity of the complexes with CT-DNA were confirmed by UV–Vis spectrum and circular dichroism (CD). The possible binding modes of the complexes with DNA were further explored by molecular docking. As the concentration of complexes 1–10 gradually increases, the fluorescence intensity of bovine serum albumin (BSA) decreases by a static quenching mechanism.

Post-administration labeling with Palladium(II) ions enables ICP-MS-based determination of the biodistribution of carbonized nanogels

Carbonized nanogels (CNGs) are carbon-based nanomaterials possessing excellent antibacterial and antiviral activities for treating infectious diseases. Thus, investigations of the biodistribution of CNGs are crucial in ensuring their biosafety for in vivo applications. In this study, we combined a labeling scheme, employing tetrachloropalladate (PdCl42−) ions to selectively label the administered CNGs in solubilized tissue samples, and an automatic sample pretreatment scheme, using a knotted reactor to effectively separate the PdCl42–-labeled CNGs from the free PdCl42− ions and the tissue matrices, to enable reliable and interference-free quantification of CNGs through measuring the signal intensities of Pd using inductively coupled plasma mass spectrometry (ICP-MS). After optimizing the labeling conditions and the separation scheme, we observed that the PdCl42− ions bound strongly to the CNGs (dissociation constant: 23.0 nM), with the method's detection limits reaching 1.6 fg L−1 and 0.9 μg L−1 within working ranges from 10−4 to 1 μg L−1 and from 1 to 1000 μg L−1, respectively. We verified the reliability and applicability of this analytical method through spike analyses of solubilized rat liver, spleen, kidney, lung, brain, and blood samples (recoveries ranging from 96 to 102%) and through analyses of these rat organ and tissue samples after giving rats an intravenous dose of CNGs (2.5 mg kg−1 body weight). The biodistribution data indicated that these administered CNGs deposited mainly in the liver, lung, and spleen at 10 min and 1 h post-administration. Our study revealed that this post-administration labeling scheme coupled with ICP-MS allows accurate determination of the biodistribution of carbonized nanomaterials.

Facile synthesis of a new covalent organic framework (COF-AYLIN) based on polyamide links and their application in C[sbnd]N coupling reaction

Among the reactions, CN coupling is one of the most important and important reactions that have taken a significant part in the industry. This study defines the design/preparation of an eco-friendly recyclable catalyst for CN coupling reaction. For this target, a new policy was designed to manufacture a new amide-based COF via the reaction amid benzidine and Benzene-1,3,5-tricarboxylic acid (BTC). BTC was activated with carbonyl diimidazole (CDI) and then reacted with benzidine for the synthesis of favorable COF (i.e., COF-AYLIN). Subsequent, the as-prepared COF was decorated via palladium ions to synthesize Pd/COF-AYLIN. The synthesized compounds were identified through the required techniques including N2 isotherms, TEM, EDX FT-IR, XRD, SEM, ICP-OES and TG-DTA. The computer simulation results possess suggested multi sheets of the 2D framework of COF-AYLIN. Consequently, It was found that palladium ions are placed between the layers and on the COF surfaces. This nanocatalyst was used in CN Cross-Coupling reaction and showed its usage in a diverse range of different functional groups with good efficiency. The reason for introducing this catalyst system is because of its advantages such as considerably high selectivity, almost complete conversion of products, good turnover frequency (TOF), high yield, convenient separation of catalyst and product. The results show that the highest efficiency of the product in the reaction was obtained in the shortest possible time with the use of Pd/COF-AYLIN.

Novel hydrazine hydrate sensor based on”fish-bait” capture mode

ABSTRACT Coordination reaction is a usual way for the concentration of metal ions in aqueous solution. In this work, 5-(5-iodine-2-pyridine azo)-2,2 amie toluene (5-PADAT) was firstly casting onto carbon glass electrode (GCE), play a role of ‘bait’; then, immersed 5-PADAT modified GCE into immersed aqueous solution containing order of magnitude ppm Palladium ions (Pd2+, play a role of ‘fishes’); ‘Fishes’ were captured by ‘bait’ with the reaction process of 5-PADAT and Pd2+, leading to the concentration of Pd2+ onto the GCE; Cyclic voltammetry was employed to reduce Pd2+ in situ, formed Pd nanoparticles (PdNPs) modified GCE. It can be used to detect the oxidation of hydrazine hydrate at a very low potential, 0.1 V.

Bent Dithienoporphyrin(2.1.2.1): Synthesis, Structure, Optical and Electronic Properties, and Metal Complexation

Four kinds of isomeric dithienoporphyrins(2.1.2.1) were prepared using two di(1H-pyrrolo-2-yl)thiophenes as building blocks and two arylaldehydes under mild acid-catalyzed conditions. The molecular conformation and optical and electronic properties of dithienoporphyrins(2.1.2.1) were investigated by NMR spectroscopy, X-ray diffraction, UV–vis absorption spectroscopy, electrochemical measurements, and theoretical calculations. The crystal structure of [2,3]F5TP has the largest angle between the two planes of the dipyrrin units among dibenzo-/dinaphthoporphyrins(2.1.2.1). This result indicates that the incorporation of thiophene subunits into a porphyrin(2.1.2.1) macrocycle results in the alteration of the molecular geometry to a more planarized structure. Dithienoporphyrin(2.1.2.1) is found to act as a ligand that can form metal complexes with nickel(II), copper(II), and palladium(II) ions. The molecular structures of the dithienoporphyrin(2.1.2.1) metal complexes exhibited bent molecular conformations. The red-shifted absorption, reversible redox processes, and theoretical calculations indicated that the electronic properties of the dithienoporphyrin(2.1.2.1) metal complexes are controlled by the inserted metal ions.

Highly adsorptive removal of palladium and platinum ions from wastewater using novel ethylenediamine-glutaraldehyde-grafted metal organic framework

Herein, a metal–organic framework (MIL-101(Cr)) was synthesized and functionalized with ethylenediamine-glutaraldehyde (ED-GA for removal of palladium (Pd2+) and platinum (Pt4+) from wastewater. The chemical structure, surface properties, morphology, and adsorption energy of the prepared materials, MIL-101(Cr) and MIL-101(Cr)/ED-GA were analyzed using several analytical techniques and density functional theory (DFT). The prepared MIL-101(Cr)/ED-GA was efficient in removing Pd2+ and Pt4+ from aqueous solution with the percentage removal reaching 95% for Pd2+ and 85% for Pt4+. Furthermore, the adsorption data demonstrated a good fit to the Langmuir isotherm model and gave the maximum adsorption capacity values of 416.17 mg g−1 for Pt4+ and and 322.6 mg g−1 for Pd2+ ions. Kinetics data obeyed a pseudo-second-order model and revealed the rapid adsorption of Pd2+ and Pt4+ ions by MIL-101(Cr)/ED-GA which reached equilibrium within 10 and 40 min, respectively. Lastly, DFT studies revealed that the adsorption of Pd2+ ions by the composite forms a more thermodynamically stable compound than adsorption of Pt4+, suggesting that the material easily interacts with Pd and high selectivity is thus expected. This was indeed confirmed by experimental selectivity test results. Owing to their high affinity for PGMs, N atoms depicted large adsorption energy values compared to other adsorption sites. The MIL-101(Cr)/ED-GA could act as an efficient and cost effective adsorbent for removal of platinum group metals from wastewater.

Alkaline ethanol oxidation on porous Fe/Pd–Fe nanostructured bimetallic electrodes

In this work, to prepare nanostructured and porous Fe/Pd–Fe bimetallic catalysts, the iron coating is applied firstly onto the copper substrate by the electrochemical deposition method. Subsequently, iron-zinc alloy coating is deposited on the underlayer iron. Eventually, by immersing this alloy coating in an alkaline solution containing palladium ions, the palladium will replace the zinc, resulting in porous Fe/Pd–Fe catalysts. The X-ray diffraction (XRD) technique was used for the characterization of the physical properties of the as-prepared electrocatalysts. Their electrocatalytic activity was studied by electrochemical methods such as cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). The XRD results showed that the zinc element was the main component of the Fe/Zn-Fe alloy and was replaced by palladium as a result of leaching-galvanic replacement. The electrochemical investigations showed that a new porous Fe/Pd-Fe bimetallic catalyst had higher electro-catalytic activity and stability than pure Pd and Fe electrodes for ethanol electro-oxidation in alkaline media. The superiority of the Fe/Pd–Fe catalyst is related to the high surface area and a synergistic effect between Fe and Pd in Fe/Pd–Fe catalysts. Therefore, the nanostructured Fe/Pd–Fe catalysts can be proposed as potential anode materials for alkaline ethanol fuel cells. A new porous Fe/Pd–Fe bimetallic catalyst shows higher electro-catalytic activity and stability than pure Pd and Fe electrodes for ethanol electro-oxidation in alkaline media. The superiority of the Fe/Pd–Fe catalyst is related to the high electrochemical surface area and a synergistic effect between Fe and Pd in Fe/Pd–Fe catalysts

Spectrophotometric Study of Palladium(II) Complexation with Elementary Amino Acids in Aqueous Solution

Complex formation of aqua palladium(II) ions with glycine (Gly), β‑alanine (β-Ala), and taurine (Tau) in aqueous solution was studied by spectrophotometric titration at I = 1.0 mol/L (HClO4 + NaClO4) and T = 25 ± 1°C. A monoligand complex appeared at pH 0 in the H‒Pd–Gly system under the conditions of our experiment; mono- and biscomplexes were formed at pH 1. In the H‒Pd‒β-Ala system, a monoligand complex was formed at pH 1 and mono- and biscomplexes were formed at pH 2. In the H‒Pd‒Tau system, a monoligand complex was formed at pH 1 and 2. Molar absorption coefficients were calculated: the peak absorption occurs at λ = 370 nm and ε = 203 L/(mol cm) for the monoligand glycinate complex [PdGly(H2O)2]+; at λ = 325 nm and ε = 274 L/(mol cm) for the biscomplex [PdGly2]0; at λ = 365 nm and ε = 342 and 297 L/(mol cm) for the β‑alaninate [Pdβ‑Ala(H2O)2]+ and taurinate [PdTau(H2O)2]+ monoligand complexes, respectively; and at λ = 330 nm and ε = 549 L/(mol cm) for the β‑alaninate biscomplex [Pdβ‑Ala2]0. Logarithmic concentration formation constants were calculated for glycinate (log β1 = 15.03 ± 0.07, and log β2 = 28.97 ± 0.28), β-alaninate (log β1 = 13.94 ± 0.05, and log β2 = 25.24 ± 0.06), and taurinate (log β1 = 9.74 ± 0.08) palladium(II) complexes.

Synthesis, Spectral Characterization, Crystal Structure, and Antioxidant Properties of novel Palladium(II) Complex from ONS Donor 1,5-bis(2-hydroxybenzylidene)thiocarbohydrazone

A new Pd(II) complex, [Pd(PPh3)(L)] (L = 1,5-bis(2-hydroxybenzylidene)thiocarbohydrazone, PPh3 = triphenylphosphine), was synthesized and characterized by FTIR, 1H NMR and UV-Vis spectroscopies and elemental analysis. The molecular structure of [Pd(PPh3)(L)] was confirmed by the single-crystal X-ray diffraction technique. Palladium ion has distorted square planar geometry according to X-ray diffraction studies. The free thiocarbohydrazone (L), potentially a pentadentate ONSNO donor, acted as a tridentate ONS donor. The antioxidant capacity of the free thiocarbohydrazone and Pd(II) complex was determined using the CUPRAC (cupric reducing antioxidant capacity) method. Also, the DPPH method was used to test the free radical scavenging activity of the free thiocarbohydrazone and Pd(II) complex. Antioxidant activity studies showed that free thiocarbohydrazone exhibited better activity than Pd(II) complex.

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.

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.

Recent Advances in the Synthesis of Five‐membered Nitrogen Heterocycles Induced by Palladium Ions and Complexes

AbstractThis review aims to collect and analyze recent results with respect to the use of varied palladium preparations in the synthesis of five‐membered nitrogen heterocycles including condensed derivatives. Results have been selected with focus on studies of the last three years. Furthermore, a common feature of all methods treated here is that the nitrogen‐containing five‐membered ring is formed via ring closing of appropriate starting materials. Selected examples discussed will reveal that a plethora of products from small monocycles to condensed multi‐ring systems can be successfully accessed. Major features are wide product ranges, high product yields and stereoselectivities often achieved under mild reaction conditions.

Synthesis and Studies Pd(II)-NHC complexes with thiosaccharinate, saccharinate or benzothiazolinate ligands

Three cis-chelating di-N-heterocyclic carbene palladium(II) complexes [Pd(X)2(di- NHC)] (X= tsac, sac and bit) tsac= thiosaccharinate, sac= saccharinate, bit= benzisothiazolinate, bearing different anionic co-ligand was synthesized and characterized. A series of palladium(II) complexes (2-5) bearing cis-chelating homo-dicarbene ligand with varying propylene-bridged (C3) and N-heterocyclic backbones (imidazole) have been synthesized by reaction of [Pd(OAc)2] with the respective diazolium bromides in DMSO, have been prepared and characterized by elemental analysis, infrared spectra and 1H NMR. These compounds are all stabilized in the sold state. The bidentate (diNHC) ligand together with two N-coordenated sac , bit and two S-coordenated tsac ligand, from the square planar coordination geometry around the palladium(II) ion.

Visible-Light-Driven Porphyrin-Based Bimetallic Metal–Organic Frameworks for Selective Photoreduction of Nitro Compounds under Mild Conditions

Selective reduction of nitroaromatics to the corresponding amines generally requires complex conditions, involving pressurized hydrogen, higher temperatures, or organic acids. In this work, we successfully prepared a series of porphyrin-based MOF photocatalysts (Pd-PMOFs, In-PMOFs, and In/Pd-PMOFs) via a facile solvothermal method for the efficient selective reduction of nitroaromatics to corresponding anilines with deionized water as the hydrogen donor. Being a new structured material (monoclinic, C52H40InN6O8Pd), on account of the abundant pore channels, strong light absorption capability, well-matched bandgap, as well as the coordination of indium ions and palladium ions, In/Pd-MOFs have excellent migration efficiency of photo-induced electrons and holes. Specifically, the In/Pd-PMOF photocatalyst manifested superior conversion (100%) and selectivity (≥80%) toward the screened nitro compounds under mild conditions. This work avoids the use of strong reductants, organic acids, and pressurized hydrogen gas as hydrogen sources, providing a promising concept for developing green catalytic systems.

Synthesis, Characterization And Antimicrobial Study of Pd(II) and Pt(II) complexes of 4-methyl-5-Imidazolecarboxaldehyde Thiosemicarbazone

Schiff bases are regarded as “privileged ligands” due to their capability to form complexes with a wide range of transition metal ions yielding stable and intensely colored metal complexes. In this study, equimolar amounts of 4-methyl-5-imidazolecarboxaldehyde and thiosemicarbazide were combined and the Schiff base 4-methyl-5-imidazolecarboxaldehyde thiosemicarbazone was prepared as a new bidentate complexing agent. The synthesized ligand was reacted with palladium (II) and platinum (II) ions yielding air-stable complexes. For characterization purpose, mass spectra and x-ray analysis of the ligand and infrared spectra, electronic spectra, thermal analysis, proton nuclear magnetic resonance and 13-carbon nuclear magnetic resonance spectra studies were carried out on the obtained ligand and its complexes. The characterization data showed that the ligand acts as a bidentate coordinate to the metal ions through azomethine nitrogen and sulfur atom. An in vitro antimicrobial investigation was also carried out for the free ligand and its metal complexes against four bacteria; Bacillus cereus, Staphylococcus aureus (Gram-positive), Escherichia coli and Salmonella typhimurium (Gram-negative) and one Fungi; Candida albicans. The results showed that the antimicrobial activity of the prepared complexes showed higher activity than the free ligand.

Facile synthesis of a new covalent organic nanosheet (CON-KEY1) based on polyamide links as an effective heterogeneous catalyst in C-C cross coupling reactions.

C-C coupling reactions represent a fundamental synthetic methodology widely employed in academic and industrial settings. Herein, we present a report on developing and synthesizing a heterogeneous catalyst that is environmentally compatible and has recycling capabilities. Furthermore, the utilization of this catalyst for C-C coupling reactions was explored. A novel amide-based CON was prepared via the reaction of a novel [2,2'-bipyridine]-5,5'-diamine (BDA) and 1,3,5-tris(4-carboxyphenyl) (TCB). TCB was activated with carbonyl diimidazole (CDI) and then reacted with BDA to synthesize favorable CON (i.e., CON-KEY1). Finally, the CON synthesized was reacted with palladium chloride ions, and the palladium-containing organocatalytic complex was decorated with the abbreviated Pd/CON-KEY1. This new heterogeneous complex was fully characterized through the required techniques, including FT-IR, EDX, XRD, TEM, SEM, ICP, TGA-DTA, N2 isotherms, and elemental mapping analysis. Computer simulation results include a multi-sheet 2D framework proposed by CON-KEY1. As a result, palladium ions were found to be arranged between the layers and on the CON surface. This heterogeneous complex functioned as a catalyst precursor in both the Suzuki-Miyaura coupling reaction of aryl boronic acids with aryl halides and the Heck reaction of aryl halides with acrylate derivatives or styrene. The desired coupling products with various functional groups were successfully attained with excellent yields of up to 98%. Simple set-up, improved yields, short reaction times, non-toxic solvents, catalyst durability, and high turnover frequency are among the distinct advantages of this synthetic method. Some other outstanding features of this catalytic system include convenient separation of catalysts and products, high yields, almost complete conversion, high selectivity, and good turnover frequency (TOF). The results show that the highest product efficiency in the reaction was achieved in the shortest possible time using Pd/CON-KEY1. Theoretical studies demonstrated the precedence of the palladium complexation with nitrogen atoms of CON-KEY1 rather than oxygen ones. Natural Bond Orbital (NBO) analysis affirmed that the system with Pd-N bonds (Eg = 0.089 eV) is more reactive with high electron conductivity compared to the Pd-O system (Eg = 0.120 eV).