Palladium Complexes Research Articles

Theoretical Studies on Relative Stability of Cationic 1,10-Phenanthroline Palladium Complexes Bearing Alkyl Groups by Using Designed Alkane Templates

Theoretical Studies on Relative Stability of Cationic 1,10-Phenanthroline Palladium Complexes Bearing Alkyl Groups by Using Designed Alkane Templates

Comparative Linkage of Novel Anti-Tumor Pd(II) Complex with Bio-Macromulecules: Fluorescence, UV-Vis, DFT, Molecular Docking and Molecular Dynamics Simulation Studies.

A novel mononuclear palladium complex, [Pd(dach)(SSA)], where dach and SSA are diaminocyclohexane and sulfosalicylic acid ligands, respectively, has been synthesized and identified utilizing analytical and spectral methods. DFT calculations, namely geometry optimization, MEP, HOMO-LUMO and NBO analysis, have been conducted at B3LYP level by aug-ccpVTZ-PP and 6-311G(d, p) basis sets. NBO and HOMO-LUMO analysis exhibited that the palladium compound is stable. MEP showed the potential sites of molecule for the interaction. By employing MTT assay, the cytotoxicity activity of the aforesaid compound was examined on K562 cell line, which revealed a proper activity compared to cisplatin. To ascertain the lipophilicity of the newly made compound, the partition coefficient measurement was accomplished, which follows the order of cisplatin < Pd(II) complex. Next, investigation of binding properties of the studied compound with DNA of calf thymus and BSA were done by spectroscopic (CD, fluorescence emission and electronic adsorption) and non-spectroscopic (viscosity measurements, DNA gel electrophoresis, molecular docking and molecular dynamics simulation) methods. The outcomes of CD and UV-Vis spectroscopy demonstrated that the title compound refolded the protein via increasing the alpha helix percentage. The data obtained from UV-Vis studies indicated the non-intercalative mutual action between Pd(II) complex with DNA. It also revealed that the Kapp magnitude of CT-DNA (7.43 × 104 M- 1) is higher than the BSA (5.17 × 103 M- 1), and L1/2 (midpoint of transition) of CT-DNA (5 µM) is lower than the BSA (5.7 µM), indicating that the complex has a greater binding affinity to CT-DNA than BSA. Fluorescence quenching mechanism of the two biomolecules by the metal complex is static and the calculated thermodynamic parameters (ΔS° < 0 and ΔH° < 0) suggested the hydrogen bonding and/ or van der Waals forces with DNA and BSA. Further, molecular docking indicated that the studied compound fits into the groove of DNA and the site I of BSA. The stability of metal compound-DNA/-BSA in the presence of H2O solvent and over the time were validated via molecular dynamics simulation.

Dioxime palladium (II) complex: Synthesis, characterization, and dual anticancer mechanisms of topoisomerase II inhibition and Bax/caspase 3

Dioxime palladium (II) complex: Synthesis, characterization, and dual anticancer mechanisms of topoisomerase II inhibition and <i>Bax</i>/caspase 3

Compounds with Chelating 3-Dimethylamino-1-propyl Ligands as Chemical Vapor Deposition Precursors. Synthesis and Characterization of M[(CH2)3NMe2]2 Complexes of Nickel(II), Palladium(II), and Platinum(II)

Compounds with Chelating 3-Dimethylamino-1-propyl Ligands as Chemical Vapor Deposition Precursors. Synthesis and Characterization of M[(CH₂)₃NMe₂]₂ Complexes of Nickel(II), Palladium(II), and Platinum(II)

C[sbnd]H activation of furanyl and thiofuranyl substrates catalyzed by trans-dichloro[1-cinnamyl-3-arylmethyl-benzimidazol-2-yliden]pyridine palladium(II) complexes

The present study explores the potential of six NHC-palladium(II) complexes derived from N-cinnamyl-N’-alkylbenzimidazolium salts, namely trans-dichloro[1,3-dicinnamyl-benzimidazol-2-yliden]pyridine palladium(II) (3a), trans-dichloro[1-cinnamyl-3-benzyl-benzimidazol-2-yliden]pyridine palladium(II) (3b), trans-dichloro[1-cinnamyl-(fluorobenzyl)-benzimidazol-2-yliden]pyridine palladium(II) (2-fluorobenzyl 3c, 3-fluorobenzyl 3d and 4-fluorobenzyl 3e,) and trans-dichloro[1-cinnamyl-(4-nitrobenzyl)-benzimidazol-2-yliden]pyridine palladium(II) (3f), as precatalyst for the cross-coupling reactions between furanyl and thiofuranyl derivatives and arylbromides via CH activation of the heterocycles. The structure of the six palladium(II) complexes has been elucidated through the use of multinuclear NMR, FT-IR and mass spectroscopy. Furthermore, the square-planar geometry of the organometallic ion was confirmed by single crystal X-ray diffraction study carried out on complex 3c. The latter complex proved to be the most effective precatalyst agent, with observed conversions higher than 78% when 4-bromoacetophenone and 1-bromonaphthalene were employed.

Stepwise Construction of Multimetallic Complexes Supported by Heteroditopic NHC/MIC Ligands

AbstractWe report the stepwise synthesis of a novel series of heterometallic gold(I)/palladium(II) complexes supported by heteroditopic imidazol‐2‐ylidene/triazol‐5‐ylidene ligands. All new compounds were characterized by means of 1H and 13C NMR spectroscopy, melting points, and elemental analyses. The versatility of the ligand platforms, additionally allows for the preparation of cationic chelate biscarbenic palladium(II) complexes through full deprotonation of the mixed azolium precursors. Characterization studies were completed by the determination of the molecular structures of some synthetic intermediates. The new biscarbenic palladium(II) complexes were tested as catalysts in the cross‐coupling of boronic acid to a variety of chloroarenes and the hydrosilylation of terminal alkynes. Both catalytic processes provide good to excellent yields under low catalyst loadings.

Palladium(II) complexes of amino acid derived ONO-tridentate enamine ligand for Suzuki-Miyaura cross-coupling reaction

Three palladium(II) complexes with an ONO-tridentate enamine ligand were synthesized by reacting the glycine derivative ligand with palladium(II) acetate in the presence of selected ancillary ligands. The structures of the Pd(II) complexes were determined through melting point, C, H, N elemental analysis, ATR-FTIR, and NMR. Additionally, the molecular structures of two complexes were confirmed using single-crystal X-ray crystallography studies, revealing that the ligand coordinates to palladium(II) via ONO-chelation, resulting in a square planar geometry around the metal center. Catalytic activities of these compounds were assessed in the Suzuki-Miyaura cross-coupling reaction of phenylboronic acid with the different aryl halides.

Magnetic Nanoparticles Immobilized Palladium Complex: A Novel and Highly Active Catalyst for Synthesis of Sulfonamides

Magnetic Nanoparticles Immobilized Palladium Complex: A Novel and Highly Active Catalyst for Synthesis of Sulfonamides

P,N-Coordinating Ylide-Functionalized Phosphines (NYPhos): A Ligand Platform for the Selective Monoarylation of Small Nucleophiles.

Palladium-catalyzed coupling reactions of small nucleophiles are of great interest, but challenging due to difficulties in selectivity control. Herein, we report the development of a new platform of P,N-ligands consisting of ylide-functionalized phosphines with aminophosphonium groups (NYPhos) to address this challenge. These phosphine ligands are easily accessible in a wide structural diversity with highly modular electronic and steric properties. Based on a family of 14 ligands the selective monoarylation of acetone as well as other challenging ketones and amides was accomplished with record-setting activities even for aryl chlorides at room temperature including late-stage functionalizations of drug molecules. Moreover, ammonia and other small primary amines could be coupled at mild conditions. Isolation and structure analyses of palladium complexes within the catalytic cycle confirmed that the P,N-coordination mode is necessary to achieve the observed selectivities. It also demonstrated the facile adjustability of the N-donor strength, which is beneficial for the targeted design of tailored P,N-ligands for future applications.

Mononuclear palladium(II) complexes of tridentate S,E,S (E = P, As) pincer ligands

The mononuclear palladium(II) complexes [Pd{PhAs(2-SC6H4)2-κ3S,S’,As}L] (L = PnBu3 (1), PMe2Ph (2)) and [Pd{(Tipp)P(2-SC6H4)2-κ3S,S’,P}(PMe2Ph)] (Tipp = 2,4,6-triisopropylphenyl) (3) bearing tridentate S,E,S (E = P or As) pincer ligands have been prepared and structurally characterised, complexes 1 and 3 also by X-ray diffraction.

Synthesis and Characterization of New Bases Derived from Nitrophenylpyrazoles, Coordination to Palladium and Antifungal Activity and Catalytic Activity in Mizoroki–Heck Reactions

In this study, we report the synthesis of eight Schiff bases (3–10) type N-heterocycle (N-het) using conventional refluxing conditions as well as different eco-friendly techniques such as grinding, thermal fusion, microwave irradiation (MWI) and ultrasound, all of them in the presence of a catalytic amount of acetic acid. These procedures had the additional advantage of being environmentally friendly and high-yield, making these protocols an alternative for Schiff-base syntheses. The obtained Schiff bases were coordinated to palladium, generating new complexes of type [Pd2Cl4(N-het)2]. Complexes [Pd2Cl4(5)2] and [Pd2Cl4(9)2] showed high activity and selectivity for a model Mizoroki–Heck C-C coupling reaction of styrene with iodobenzene and bromobenzaldehydes. All compounds and complexes were evaluated for antifungal activity against clinically important fungi such as Candida albicans and Cryptococcus neoformans. Although the Schiff bases (3–10) showed low antifungal activity against both fungi, some of their palladium complexes such as [Pd2Cl4(3)2], [Pd2Cl4(5)2], [Pd2Cl4(8)2] and [Pd2Cl4(10)2] showed comparatively higher antifungal effects mainly against C. neoformans. The product of the Mizoroki–Heck-type C-C coupling reactions, 4-styrylbenzaldehyde, was isolated and purified to be later used in the synthesis of four new nitrophenylpyrazole derivatives of styrylimine, which also displayed antifungal activity, especially against C. neoformans.

N-alkylbenzimidazolepalladium(II) complexes: Synthesis and their catalytic activities in direct C-H functionalization of pyrrole, furan and 2-acetylthiophene

Herein, we reported the synthesis of six new palladium complexes (2a-2f) containing benzimidazole core and examined their catalytic activities in the direct arylation of heteroaromatic species with aryl bromides. For this purpose, a new series of palladium(II) complexes bearing N-coordinated benzimidazole complexes have been synthesized and fully characterized by elemental analysis, FT-IR, 1H NMR and 13C NMR spectroscopies. Additionally, the structures of the complexes 2a-2e have been characterized by X-ray crystallography. Further, direct arylation reactions, using KOAc as base and DMAc as solvent under inert conditions, were carried out with the synthesized complexes in the presence of various aryl bromides, and 1-methylpyrrole-2-carboxaldehyde, furfuryl acetate, 2-acetylfuran and 2-acetylthiophene. Moreover, moderate to high yields were obtained in the direct arylation of heteroarenes and aryl bromides under 1 % mol catalyst loading conditions.

Relevance of Oxocyclam from Palladium(II) Coordination to Radiopharmaceutical Development.

We provide a comprehensive study of the coordination of oxocyclam with palladium(II), including presentation of a novel bifunctional analogue, p-H2N-Bn-oxocyclam, bearing an aniline pendant. The complexation of palladium(II) with oxocyclam was examined by various techniques, including NMR analysis and potentiometric titrations which revealed that the Pd(II) complex can adopt different configurations such as trans-I and trans-III. In addition, oxocyclam forms a thermodynamically stable palladium(II) complex, the stabilization being attributed to the deprotonation of the amide function. The crystal structures of [Pd(H-1oxocyclam)]+ and [Pd(oxocyclam)]2+ were obtained, revealing the structural details previously anticipated, including, in the second case, the presence of the proton on the carbonyl oxygen atom. Additionally, the study explored the redox behavior of the Pd(II)-oxocyclam complex through reduction and oxidation voltammograms at different pH values. Successful 109Pd-labeling of oxocyclam and p-H2N-Bn-oxocyclam at pH 3.5 demonstrated high labeling efficiencies, whatever the species formed. The stability of the radiocomplexes was assessed and moderate transchelation toward EDTA was observed. Overall, oxocyclam displayed favorable properties for Pd(II) coordination and radiolabeling, suggesting its potential as a chelating agent for this metal in palladium-based applications.

New palladium(II) metallates containing ON donor Schiff base ligand. synthesis, spectral characterization, x-ray crystallography, photo physical and in vitro cytotoxicity

Two new Palladium(II) complexes were synthesized by reacting (3‑hydroxy-naphthalene-2-carboxylic thiophen-2-ylmethylene-hydrazide) with [PdCl2(EPh3)2] (E = P, As). The complexes [Pd(L-N,O)Cl(PPh3)] (1) [Pd(L-N,O)Cl(AsPh3)] (2), HL = 3‑hydroxy-naphthalene-2-carboxylicthiophen-2-ylmethylenehydrazide formation was analysed through various spectroscopic investigations (IR, Uv-Visble, 1HNMR ) and structural confirmation was obtained from single crystal x-ray crystallography, which indicated that the complex 1 having distorted square planar geometry. DNA/protein binding ability of the ligand and complexes were commenced using absorption and emission titrations and found that the complex 2 have better binding ability with tyrosine and tryptophan residues and by quenching the fluorescence of BSA through static quenching mechanism. Their antioxidant and in vitro anticancer activities were assessed, where complex 2 displayed better radical scavenging properties and cancer cell death inducing ability. Further, DAPI staining assay was performed to detect the mode of cell death and found complex 2 having better towards to cell death.

Metal‐Mediated Synthesis of a Mixed Arduengo‐Fischer Carbodicarbene Ligand

Carbodicarbenes are strong C‐donor ligands, which have found numerous applications in organometallic and main group element chemistry. Herein, we report a structurally distinct carbodicarbene ligand, which is formed by dinitrogenative coupling of a Fischer carbene complex with an N‐heterocyclic diazoolefin. The resulting carbonyl complex serves as a stable source for the mixed Arduengo‐Fischer carbodicarbene ligand. Facile ligand transfer reactions were demonstrated to occur with gold(I), copper(I), palladium(II), and rhodium(I) complexes.

Metal-Mediated Synthesis of a Mixed Arduengo-Fischer Carbodicarbene Ligand.

Carbodicarbenes are strong C-donor ligands, which have found numerous applications in organometallic and main group element chemistry. Herein, we report a structurally distinct carbodicarbene ligand, which is formed by dinitrogenative coupling of a Fischer carbene complex with an N-heterocyclic diazoolefin. The resulting carbonyl complex serves as a stable source for the mixed Arduengo-Fischer carbodicarbene ligand. Facile ligand transfer reactions were demonstrated to occur with gold(I), copper(I), palladium(II), and rhodium(I) complexes.

Exploring Raloxifene-Based Metallodrugs: A Versatile Vector Combined with Platinum(II), Palladium(II) and Nickel(II) Dichlorides and Carborates against Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) poses challenges in therapy due to the absence of target expression such as estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Frequently, the treatment of TNBC involves the combination of several therapeutics. However, an enhanced therapeutic effect can be also achieved within a single molecule. The efficacy of raloxifene can be improved by designing a raloxifene-based hybrid drug bearing a 2,2'-bipyridine moiety (2). Integration of platinum(II), palladium(II), and nickel(II) complexes into this structure dramatically changed the cytotoxicity. The platinum(II) dichloride complex 3 did not demonstrate any activity, while palladium(II) and nickel(II) dichloride complexes 4 and 5 exhibited various cytotoxic behavior towards different types of hormone-receptor positive (HR+) cancer and TNBC cell lines. The replacement of the two chlorido ligands in 3-5 with a dicarbollide (carborate) ion [C2B9H11]2- resulted in reduced activity of compounds 6, 7, and 8. However, the palladacarborane complex 7 demonstrated higher selectivity towards TNBC. Furthermore, the mechanism of action was shifted from cytotoxic to explicitly cytostatic with detectable proliferation arrest and accelerated aging, characterized by senescence-associated phenotype of TNBC cells. This study provides valuable insights into the development of hybrid therapeutics against TNBC.

Design, structural characterization, DFT, molecular docking, and chemotherapeutic activity of novel platinum(II) and palladium(II) complexes derived from Metformin-based Schiff base

Two novel bidentate Schiff bases ligands derived from Metformin with aldehydic molecules, including o-Ethoxy benzaldehyde (L1) and thiophene-2-carbaldehyde (L2) and Pt(II) and Pd(II) complexes were prepared. Numerous techniques were used to study the ligands and their metal complexes, including mass spectroscopy, IR, UV–Vis, molar conductivity, magnetic moment measurement, 1HNMR, PXRD, and 13CNMR. The preceding two Schiff bases were coordinated to Pd (II) and Pt (II) in the molar ratio of (1:1) (M:L) with the molecular structure [MLCl2]. The chemical quantum characteristics were calculated, and Schiff bases' optimized geometric structures and their complexes were revised theoretically. The MCF-7 breast cancer model was used to test the anticancer effects of metformin Schiff bases and their complexes in vitro. Additionally, using the EGFR tyrosine kinase of the selected proteins, a molecular docking study was carried out to learn more about the docking active site interactions. Ultimately, the conventional DPPH method was used to assess the antioxidant activity of the free ligands and their metal chelates. Pt (II) complexes demonstrated greater free radical scavenging activity than ascorbic acid. Furthermore, Pt (II) complexes showed more effective interactions with the selected mTOR protein, which is assumed to help the COVID-19 virus proliferate. Thus, Pt (II) has a bright future in the realm of chemotherapy.

Recyclable Palladium-Catalyzed Carbonylative Coupling of Aryl Halides and Organoaluminum Compounds with tert-Butyl Iso­cyanide as CO Equivalent Leading to 1,2-Diketones

AbstractAn efficient heterogeneous palladium-catalyzed carbonylative coupling of aryl halides and organoaluminum compounds has been developed using tert-butyl isocyanide as CO equivalent. The carbonylation reaction proceeds smoothly in toluene with KOtBu as a base at 100 °C by using 10 mol% of an SBA-15-anchored bidentate phosphine palladium(0) complex [2P-SBA-15-Pd(0)] as the catalyst and provides a general and practical approach for the assembly of 1,2-diketones in good to excellent yields. This heterogenized palladium catalyst can be readily separated and recovered via a simple centrifugation process and reused for more than seven cycles with almost consistent catalytic efficiency.

Catalytic Properties of Sterically Shielded Carbene Complexes of Palladium in C–C and C–N Coupling Reactions of Haloarenes

Catalytic Properties of Sterically Shielded Carbene Complexes of Palladium in C–C and C–N Coupling Reactions of Haloarenes