Synergistic manipulation of sulfur vacancies and palladium doping of In2S3 for enhanced photocatalytic H2 production.

In this study, a simple one-pot synthesis process is employed to introduce Pd dopant and abundant S vacancies into In2S3 nanosheets. The optimized Pd-doped In2S3 photocatalyst, with abundant S vacancies, demonstrates a significant enhancement in photocatalytic hydrogen evolution. The joint modification of Pd doping and rich S vacancies on the band structure of In2S3 result in an improvement in both the light absorption capacity and proton reduction ability. It is worth noting that photogenerated electrons enriched by S vacancies can rapidly migrate to adjacent Pd atoms through an efficient transfer path constructed by Pd-S bond, effectively suppressing the charge recombination. Consequently, the dual-defective In2S3 shows an efficient photocatalytic H2 production rate of 58.4 ± 2.0 µmol·h-1. Additionally, further work has been conducted on other ternary metal sulfide, ZnIn2S4. Our findings provide a new insight into the development of highly efficient photocatalysts through synergistic defect engineering.

Surface crystallized supramolecular to achieve highly dispersed ultrafine nano-palladium in-situ deposition to promote thermal/electrocatalytic reduction.

To promote the greening and economization of industrial production, the development of advanced catalyst manufacturing technology with high activity and low cost is an indispensable part. In this study, nitrogen-doped hollow carbon spheres (NHCSs) were used as anchors to construct a supramolecular coating formed by the self-assembly of boron clusters and ß-cyclodextrin by surface crystallization strategy, with the help of the weak reducing agent characteristics of boron clusters, highly dispersed ultra-small nano-palladium particles were in-situ embedded on the surface of NHCSs. The deoxygenation hydrogenation of nitroaromatics and the reduction of nitrate to ammonia were used as the representatives of thermal catalytic reduction and electrocatalytic reduction respectively. The excellent properties of the constructed Pd/NHCSs were proved by the probe reaction. In the catalytic hydrogenation of nitroaromatics to aminoaromatics, the reaction kinetic rate and activation energy are at the leading level. At the same time, the constructed Pd/NHCSs can also electrocatalytically reduce nitrate to high value-added ammonia with high activity and selectivity, and the behavior of Pd/NHCSs high selectivity driving nitrate conversion was revealed by density functional theory and in situ attenuated total reflection Fourier transform infrared (ATRFTIR) technique. These results all reflect the feasibility and superiority of in-situ anchoring ultra-small nano-metals as catalysts by surface crystallization to build a supramolecular cladding with reducing properties, which is an effective way to construct high-activity and low-cost advanced catalysts.

Support electron inductive effect of Pd-Mn/Ni foam catalyst for robust electrocatalytic hydrodechlorination.

Structural regulation of Pd-based electrocatalytic hydrodechlorination (EHDC) catalyst for constructing high-efficient cathode materials with low noble metal content and high atom utilization is crucial but still challenging. Herein, a support electron inductive effect of Pd-Mn/Ni foam catalyst was proposed via in-situ Mn doping to optimize the electronic structure of the Ni foam (NF), which can inductive regulation of Pd for improving the EHDC performance. The mass activity and current efficiency of Pd-Mn/NF catalyst are 2.91 and 1.34 times superior to that of Pd/NF with 2,4-dichlorophenol as model compound, respectively. The Mn-doped interlayer optimized the electronic structure of Pd by bringing the d-state closer to the Fermi level than Pd on the NF surface, which optimizied the binding of EHDC intermediates. Additionally, the Mn-doped interlayer acted as a promoter for generating H* and accelerating the EHDC reaction. This work presents a simple and effective regulation strategy for constructing high-efficient cathode catalyst for the EHDC of chlorinated organic compounds.

Total Synthesis of Ryanodane Diterpenoids Garajonone and 3-epi-Garajonone.

Ryanodane diterpenes are structurally complex natural products that are well-known for their high degree of oxidation and the challenges associated with synthesizing them within the terpene class. Herein, we present a two-stage synthetic strategy that draws inspiration from the broad biosynthesis of terpenes, allowing us to successfully achieve the first chemical synthesis of garajonone, a ryanodane diterpenoid that occurs naturally at low abundance, as well as its epimer, 3-epi-garajonone. The key to this success lies in the rapid construction of the carbon framework of target molecule by employing an early-stage palladium-catalyzed Heck/carbonylative esterification cascade annulation, followed by successive late-stage selective redox manipulation to establish the desired oxidation state of the molecule. This research not only showcases the synthesis of garajonone and its epimer but also provides a platform for the chemical synthesis of other members and analogs within this complex diterpenoid family.

Nanoscale Imaging of Palladium-Enhanced Photocatalytic Reduction of 4-Nitrothiophenol on Tungsten Disulfide Nanoplates.

Two-dimensional (2D) dichalcogenides are modern nanomaterials with unique physical and chemical properties. These materials possess band gaps in the infrared and visible regions of the electromagnetic spectrum that can be tuned by their molecular composition. Excitons generated as a result of such light-matter interactions are capable of catalyzing chemical reactions in molecular analytes present on the dichalcogenide surfaces. However, the photocatalytic properties of such nanomaterials remain poorly understood. In the current study, we utilize tip-enhanced Raman spectroscopy (TERS) to examine photocatalytic reduction of 4-nitrothiophenol (4-NTP) to p,p'-dimercaptoazobisbenzene (DMAB) on tungsten disulfide (WS2) nanoplates and WS2 coupled with palladium nanoparticles (WS2@PdNPs). Our results indicate that although both WS2 and WS2@Pd were capable of reducing 4-NTP into DMAB, the metallic hybrid demonstrated much greater yield and rates of DMAB formation compared to WS2 nanoplate. These results indicate that coupling of catalytic metals to dichalcogenides could be used to enhance their catalytic properties.

Acidic oral environment's potential contribution to palladium-induced systemic contact dermatitis: Case report.

Acidic oral environments may trigger systemic contact dermatitis via ionization of metals, including palladium. A patch test revealed a late delayed positive response to palladium, emphasizing the need for nuanced diagnostic approaches for allergy management.

Synthesis, Structural Characterization and Catalytic Application of Ferrocenyl based Bis(pyrazolyl) Palladium Complexes.

Here we report, synthesis of ferrocenyl based bis(pyrazolyl) palladium complexes. The catalytic utility of the complexes in the cross-coupling of triarylbismuthanes and aryl bromides was evaluated. Our ferrocenyl based palladium complex showed wide substrate scope for both triarylbismuthanes and aryl bromides. Further, the current catalytic system also showed superior activity over the well-established palladium-phosphine catalytic system using triarylbismuthanes as reagents.

N-Doped and Bowl-Shaped Azabenzo[3,4]azulenofluorene: Synthesis and Characterization of Bridged Aza-Triarylamines.

Triarylamines are frequently employed as electron donor functional groups in a variety of organic electronic materials. We herein report the synthesis and in-depth characterisation of aza-analogues of fully bridged triarylamines, consisting of 5-, 6- and 7-membered rings. The impact of nitrogen doping and π-extension on the structural, electronic and optical-properties of these contorted heteroaromatic PAHs is thoroughly investigated and paves the way for an improved understanding of the structure-property relationships.

New Tricyclic Aryl Quinazoline Derivatives by Suzuki-Miyaura Cross-Coupling.

A number of new deoxyvasicinone (2,3-dihydropyrrolo[2,1-b]quinazolin-9(1H)-one) and mackinazolinone (6,7,8,9-tetrahydro-11H-pyrido[2,1-b]quinazolin-11-one) derivatives with aryl substituents at C7/C8 and at C5 are reported. These compounds are rare representatives of their kind and were prepared in high yields by Suzuki-Miyaura cross-coupling reactions between 7-bromo-2,3-dihydro[2,1-b]quinazoline-9-(1H)-one, 5,7-dibromo-2,3-dihydro[2,1-b]quinazoline-9-(1H)-one or 8-bromomackinazolinone and respective arylboronic acids with palladium acetate as the catalyst. The products were characterized spectroscopically and, in addition, by X-ray crystal structure analyses in six cases.

Visible-light induced effective and sustainable remediation of nitro organics pollutants using Pd-doped ZnO nanocatalyst.

Nitroaromatic compounds represent a class of highly toxic pollutants discharged into aquatic environments by various industrial activities, posing significant threats to ecological integrity and human health due to their persistent and hazardous nature. In this study, Pd-doped ZnO nanoparticles were investigated as a potential solution for the degradation of nitro organics, offering heightened photocatalytic efficacy and prolonged stability. The synthesis of Pd-doped ZnO NPs was achieved via the hydrothermal method, with subsequent analysis through XRD spectra and XPS confirming successful Pd doping within the ZnO matrix. Characterization through FESEM and HRTEM unveiled the heterogeneous morphologies of both undoped and Pd-doped ZnO nanoparticles. Additionally, UV-vis and PL spectroscopy provided insights into the optical properties, chemical bonding, and defect structures of the synthesized Pd-doped ZnO NPs. Pd doping induces a redshift in ZnO's absorption spectra, reducing the bandgap from 3.12 to 2.94 eV as Pd concentration rises from 0 to 0.2 wt.%. The photocatalytic degradation, following pseudo-first-order kinetics, achieved 90% nitrobenzene abatement (200 µg/L, pH 7) under visible light within 320 min with a catalyst loading of 16 µg/mL. The photocatalytic efficacy of 0.08 wt% Pd-doped ZnO (k = 0.058 min⁻1) exhibited a 25-fold enhancement compared to bare ZnO (k = 3.1 × 10-4 min-1). Subsequent quenching and ESR experiments identified hydroxyl radicals (OH•) as the predominant active species in the degradation mechanism. Mass spectrometry analysis unveiled potential breakdown intermediates, illuminating a plausible degradation pathway. The investigated Pd-doped ZnO nanoparticles demonstrated reusability for up to five successive treatment cycles, offering a sustainable solution to nitro organics contamination challenges.

Highly Durable Chemoresistive Micropatterned PdAu Hydrogen Sensors: Performance and Mechanism.

Hydrogen (H2) is a promising alternative energy source for Net-zero, but the risk of explosion requires accurate and rapid detection systems. As the use of H2 energy expands, sensors require high performance in a variety of properties. Palladium (Pd) is an attractive material for H2 detection due to its high H2 affinity and catalytic properties. However, poor stability caused by volume changes and reliability due to environmental sensitivity remain obstacles. This study proposes a micropatterned thin film of PdAu with optimized composition (Pd0.62Au0.38) as a chemoresistive sensor to overcome these issues. At room temperature, the sensor has a wide detection range of 0.0002% to 5% and a fast response time of 9.5 s. Significantly, the sensor exhibits excellent durability for repeated operation (>35 h) in 5% H2 and resistance to humidity and carbon monoxide. We also report a negative resistivity change in PdAu, which is opposite to that of Pd. Density functional theory (DFT) calculations were performed to investigate the resistance change. DFT analysis revealed that H2 penetrates specific interstitial sites, causing partial lattice compression. The lattice compression causes a decrease in electrical resistance. This work is expected to contribute to the development of high-performance H2 sensors using Pd-based alloys.

Advances in Group-10 Transition Metal Dichalcogenide PdSe2-Based Photodetectors: Outlook and Perspectives.

The recent advancements in low-dimensional material-based photodetectors have provided valuable insights into the fundamental properties of these materials, the design of their device architectures, and the strategic engineering approaches that have facilitated their remarkable progress. This review work consolidates and provides a comprehensive review of the recent progress in group-10 two-dimensional (2D) palladium diselenide (PdSe2)-based photodetectors. This work first offers a general overview of the various types of PdSe2 photodetectors, including their operating mechanisms and key performance metrics. A detailed examination is then conducted on the physical properties of 2D PdSe2 material and how these metrics, such as structural characteristics, optical anisotropy, carrier mobility, and bandgap, influence photodetector device performance and potential avenues for enhancement. Furthermore, the study delves into the current methods for synthesizing PdSe2 material and constructing the corresponding photodetector devices. The documented device performances and application prospects are thoroughly discussed. Finally, this review speculates on the existing trends and future research opportunities in the field of 2D PdSe2 photodetectors. Potential directions for continued advancement of these optoelectronic devices are proposed and forecasted.

Crystal structure and Hirshfeld surface analysis of di-chlorido-[2-(3-cyclo-pentyl-1,2,4-triazol-5-yl-κN 4)pyridine-κN]palladium(II) di-methyl-formamide monosolvate.

This study presents the synthesis, characterization and Hirshfeld surface analysis of the title mononuclear complex, [PdCl2(C12H14N4)]·C3H7NO. The compound crystalizes in the P21/c space group of the monoclinic system. The asymmetric unit contains one neutral complex Pd(HL c-Pe)Cl2 [HL c-Pe is 2-(3-cyclo-pentyl-1,2,4-triazol-5-yl)pyridine] and one mol-ecule of DMF as a solvate. The Pd atom has a square-planar coordination. In the crystal, mol-ecules are linked by inter-molecular N-H⋯O and C-H⋯N hydrogen bonds, forming layers parallel to the bc plane. A Hirshfeld surface analysis showed that the H⋯H contacts dominate the crystal packing with a contribution of 41.4%. The contribution of the N⋯H/H⋯N and H⋯O/O⋯H inter-actions is somewhat smaller, amounting to 12.4% and 5%, respectively.

Allosteric Inhibition of the ß2-Adrenergic Receptor: Design and Synthesis of Cmpd-15 Analogs.

We designed and synthesized 27 new amide and dipeptide derivatives containing a substituted phenylalanine as negative allosteric modulators (NAMs) for the beta-2 adrenergic receptor (ß2AR). These analogs aimed to improve the activity of our lead compound, Cmpd-15, by introducing variations in three key regions: the meta-bromobenzyl methylbenzamide (S1), para-formamidophenylalanine (S2), and 1-cyclohexyl-1-phenylacetyl (S3) groups. The synthesis involved the Pd-catalyzed ß-C(sp3)-H arylation of N-acetylglycine with 1-iodo-4-substituent-benzenes as the key step. GloSensor cAMP accumulation assay revealed that six analogs (A1, C5, C6, C13, C15 and C17) surpass Cmpd-15 in ß2AR allosteric function. This highlights the crucial role of the S1 region (meta-bromobenzyl methylbenzamide) in ß2AR allostery while suggesting potential replaceability of the S2 region (para-formamidophenylalanine). These findings serve as a valuable springboard for further optimizing Cmpd-15, potentially leading to smaller, more active, and more stable ß2AR-targeting NAMs.

Photoinduced Pd-Catalyzed Direct Sulfonylation of Allylic C-H Bonds.

Allylic sulfones are valuable motifs due to their medicinal and biological significance and their versatile chemical reactivities. While direct allylic C-H sulfonylation represents a straightforward and desirable approach, these methods are primarily restricted to terminal alkenes, leaving the engagement of the internal counterparts a formidable challenge. Herein we report a photocatalytic approach that accommodates both cyclic and acyclic internal alkenes with diverse substitution patterns and electronic properties. Importantly, the obtained allylic sulfones can be readily diversified into a wide range of products, thus enabling formal alkene transposition and all-carbon quaternary center formation through the sequential C-H functionalization.

A six-membered N-heterocyclic polyionic liquids with palladium nanoparticles as a heterogeneous catalyst for the multicomponent one-pot reaction of carbon dioxide.

A series of heterogeneous catalysts, designated as POP-n-Pd (where n = 1, 2, 3, or 4), were synthesized by polymerizing a six-membered N-heterocyclic compound with an alkyl substituted group monomer (S1), using divinylbenzene (DVB) as crosslinkers. This process was followed by the incorporation of palladium (Pd) nanoparticles. The impact of the substituted group and the S1:DVB ratio in the catalysts, together with the reaction conditions, was investigated to assess their influence on the catalytic performance in converting propylamine, carbon dioxide (CO2) and 4-iodoanisole to oxazolidinones. The POP-1-Pd catalyst, featuring a methyl substituted group and a S1:DVB ratio of 1:4, exhibited remarkable efficiency, resulting in an excellent yield of 96 % under room temperature and ambient pressure conditions. Furthermore, it has demonstrated wide applicability across a variety of substrates and in the treatment of lime kiln exhaust gas. Additionally, POP-1-Pd can be used in a gram-scale reaction and maintains its performance after six recycles, with no significant decline in yield. The possible catalytic mechanism is proposed as follows: the catalyst's pores adsorb both CO2 and substrates, creating a high concentration reactant enrichment microenvironment. This facilitates the activation of both CO2 and substrates by the imidazole moiety and Pd nanoparticles in the catalyst, thereby generating oxazolidinones.

Palladium-catalyzed C(sp3)-H activation in a monoterpene-based compound under mild conditions: a combined experimental and theoretical mechanistic study.

The first example of the palladium-catalyzed sp3 C-H bond activation in a monoterpene-based compound has been observed in the reaction of PdCl2 with a (+)-3-carene-based ligand HL (HL = N-((1aS,3S,7bR)-1,1,3-trimethyl-7-phenyl-5-(pyridin-2-yl)-1a,2,3,7b-tetrahydro-1H-cyclopropa[f]quinolin-3-yl)acetamide), which yielded the [PdLCl] complex. In contrast to the vast majority of C(sp3)-H activation reactions which require prolonged heating and mixing due to the inert character of the corresponding bond, the reaction reported herein proceeds rapidly under mild conditions. A theoretical insight into the ligand deprotonation has been performed by DFT calculations. The mechanism of the C-H activation involves (i) simultaneous coordination of the CH3 group of HL to the Pd2+ ion and decoordination of the Cl- anion with consequent formation of a Cl⋅⋅⋅H-N hydrogen bond with the amide group, (ii) approximation of the out-of-sphere Cl- anion to one of the hydrogen atoms of the CH3 group mediated by the crane motion of the amide group and (iii) the ejection of the HCl molecule, which increases the entropy of the system and serves as a driving force for the reaction.

Pd Catalysts Supported on Mixed Iron and Titanium Oxides in Phenylacetylene Hydrogenation: Effect of TiO2 Content in Magnetic Support Material.

Recently, Pd catalysts supported on magnetic nanoparticles (MNPs) have attracted a great attention due to their ability of easy separation with an external magnet. Modification of MNPs is successfully used to obtain Pd magnetic catalysts with enhanced catalytic activity. In this work, we discussed the effect of titania content in TiO2/MNPs support materials on catalytic properties of Pd@TiO2/MNPs catalysts in phenylacetylene hydrogenation. TiO2/MNPs composites were prepared by simple ultrasound-assisted mixing of TiO2 and MNPs, synthesized by co-precipitation method. This was followed by deposition of palladium ions on the mixed metal oxides using NaOH as precipitant. The supports and catalysts were characterized using XRD, BET, STEM, EDX, XPS, and a SQUID magnetometer. Pd nanoparticles (5-6 nm) formed were found to be homogeneously distributed on support materials representing the well-mixed metal oxides with TiO2 content of 10, 30, 50, or 70%wt. Testing of the catalysts in phenylacetylene hydrogenation showed that their activity increased with increasing TiO2 content, and the process was faster in alkali medium (pH = 10). The hydrogenation rates of triple and double C-C bonds on Pd@70TiO2/MNPs achieved 9.3 × 10-6 mol/s and 23.1 × 10-6 mol/s, respectively, and selectivity to styrene was 96%. The catalyst can be easily recovered with an external magnet and reused for 12 runs without significant degradation in the catalytic activity. The improved catalytic properties of Pd@70TiO2/MNPs can be explained by the fact that the surface of the support is mainly composed of TiO2 particles, affecting the state and size of Pd species.

Breaking New Ground towards Innovative Synthesis of Palladacycles: The Electrochemical Synthesis of a Tetranuclear Thiosemicarbazone-[C,N,S] Palladium(II) Complex.

The electrochemical oxidation of anodic metals (M = nickel and palladium) in an acetonitrile solution of the thiosemicarbazone ligands (E)-2-(1-(4-methoxyphenyl)ethylidene)-N-methylhydrazine-1-carbothioamide (a), (E)-2-(1-(p-tolyl)ethylidene)hydrazine-1-carbothioamide (b), and (E)-N-phenyl-2-(1-(p-tolyl)ethylidene)hydrazine-1-carbothioamide (c) yielded the homoleptic complexes [ML2], 1a, 1b, 1c, and 2c and [M4L4], 2a as air-stable solids. The crystal structures for 1a, 1b, 1c, and 2c show the ligands in a transoid disposition with the [S,S] and [N,N] donor atom pairs occupying cis positions on the nearly square planar coordination plane of the metal. The structure for 2a of S4 symmetry comprises a tetranuclear palladacycle where the metalated ligands are arranged around a central Pd4S4 environment: a crown ring with alternating palladium and sulfur atoms. The latter complex is the first example of an electrochemical preparation of a cyclometalated palladium compound, marking a milestone in the chemistry of such species. The compounds have been fully characterized by elemental microanalysis, mass spectrometry, infrared (IR), and 1H nuclear magnetic resonance (NMR) spectra.

High N2-selectivity of nitrite reduction by palladium-laden nanocomposite with self-sufficient electron donators.

Selectively reducing nitrite to gaseous nitrogen (N2) with an effective and recyclable fashion stands as an attractive alternative for treating the relevant wastewater. Herein, a Pd-based nanocomposite (Pd@EDA-CMPS) was subtly assembled by encapsulating Pd(0) nanoparticles into a porous polystyrene carrier, which was aforehand functionalized with ethylenediamine (EDA) as the endogenous electron donator. Systematical macroscopic experiments confirm that the pre-grafted EDA groups can substantially stimulate the catalytic activity of the laden Pd(0) nanoparticles with high removal efficiency and N2 selectivity of Pd@EDA-CMPS toward nitrite; specifically, high N2 selectivity (86%) was achieved by Pd@EDA-CMPS with an excellent anti-interference ability against competing anion and a broad pH-range applicability (4-11), whereas no N2 production was detected for its counterparts (CMPS, EDA-CMPS, and Pd@CMPS). Spectroscopic analyses reveal that the grafted EDA groups played a decisive role in the formation of H-loaded Pd(0) nanoparticles inside the porous substrate, which joint with the unique pH-buffering ability of EDA drove the reaction to the production of nitrogen (N2) rather than ammonia (NH3). The exhausted Pd@EDA-CMPS can be promisingly regenerated by NaOH (eluting) and NaBH4 (restoring) solution without obvious loss in treatment capacity and N2 selectivity. This work provides a feasible strategy for catalytically reducing nitrite into N2 without the provision of exogenous reductor such as hydrogen.