Strategy For Synthesis Research Articles

Ionic Porous Aromatic Frameworks Embedding Polyoxometalates for Heterogeneous Catalysis.

Porous aromatic frameworks (PAFs) are promising functional porous solids known for their feasible amenability and extraordinary stability. When the frameworkmodified by ionic functional groups, the given ionic PAFs (iPAFs) exhibited charged channels for adsorption, separation and catalysis. However, the surface areas of ionic porous frameworks are usually lower than the neutral ones, and their synthesis limited by specific strategies and complex modifying processes. To overcome these problems, we proposed an intuitive route to construct ionic porous framework with high specific surface area, through a multivariable synthesis strategy. Herein, multivariate ionic porous aromatic framework (MTV-iPAFs) material named PAF-270 was synthesized from readily available building units with ionic functional groups. PAF-270 exhibited hierarchical structure with the highest specific surface area among reported imidazolium functionalized PAFs. Leveraging its physical and chemical properties, we explored its availability for polyoxometalates loading and heterogeneous catalysis. PAF-270 exhibited high adsorption capacity up to 50% for both H3O40PW12 (HPW) and (NH4)5H6PV8Mo4O40 (V8). HPW@PAF-270 and V8@PAF-270 exhibited excellent catalytic abilities for oleic acid esterification and extractive oxidative desulfurization, respectively. Due to the stability of PAFs, these materials also showed remarkable resistance to temperature and pH changes. These results highlight the potential application of MTV-iPAFs as functional porous materials.

The Synthesis of Amino-Acid-Anchored Two-Dimensional Silicoaluminophosphates and Congo Red Adsorption Application.

Two-dimensional (2D) materials with nanometer thickness have the advantage of a large specific surface area and excellent surface accessibility. They have great potential for adsorption, catalysis, and many other applications. 2D zeolitic silicoaluminophosphates (SAPOs) can be synthesized through a dual structure directing agent (SDA) strategy. But the materials have been primarily used in their organic-free form. In this work, we demonstrate that the same synthesis strategy is effective for developing amino-acid-anchored 2D SAPOs through a one-step synthesis. Because of the addition of amino acids, the surficial amino and carboxylic groups serve as active sites for adsorption and catalysis. Congo red adsorption is used to evaluate the potential of using the organic functional groups as active adsorption sites. The 2D SAPO materials have demonstrated excellent Congo red removal efficiency with close to complete removal for certain concentrations. The effects of the amino acid concentration and hydrothermal synthesis time on material morphology development will be discussed. Thorough characterization by SEM, TEM, FTIR, XRD, and nitrogen adsorption has been done to reveal the properties of the amino-acid-anchored 2D SAPOs.

Optimizing the Synthesis Strategy of the Chlorinated Chain Characteristic to the Enacyloxin Series Using Models.

In this paper are presented the results of the preliminary studies conducted on two model substrates that allowed the testing of various strategies and set the proper conditions that thereafter culminated in the synthesis of the C1-C23 chain of enacyloxin-IIa and its congeners. Innovative strategic options were explored on each model allowing the stereochemical control of the following two elements: (a) the 2E, 4E, 6E, 8E, and 10Z chlorinated undecapentaenoic chain, thanks to Z-selective Kaneda's alkyne allylchlorination and an E-selective Pd/Cu allene-alkyne coupling and (b) the unusual syn-anti -OH/-Cl/-OCONH2 C17-C19 triad, thanks to a highly diastereoselective Mukaiyama aldol reaction.

Organocatalytic [3+2] annulation of β-tetralones with α, β-unsaturated aldehydes

The NBS-mediated organocatalytic cascade synthesis of 4,5-dihydronaphtho[2,1-b]furan-1-carbaldehydes from α, β -unsaturated aldehydes and 2-tetralones have been developed. In this synthesis strategy, the C1 of in-situ-generated brominated 2-tetralone as an identical twin electron donor-acceptors, and the Cβ and Cα of enals as the heterogenous twin electron acceptor-donors. The process has been realized by a synergistic amine/ p-TSA catalyzed one-pot cascade Michael addition-cyclopropanation-ring opening-Oxa Michael addition in mild condition and without the use of transition metals.

Deciphering the Origin of Regioselectivity in Ru(II)-Catalyzed C-H Annulation of N-Chlorobenzamides with 1,3-Diynes.

Understanding the reaction mechanism and origin of regioselectivity in transition metal-catalyzed C-H activation/annulation reactions with 1,3-diynes has remained an intriguing challenge. In this article, to establish the mechanism and decipher the origin of regioselectivity, we report a detailed computational density functional theory-based mechanistic investigation on the recently developed Ru(II)-catalyzed [4 + 2] annulation of N-chlorobenzamides with 1,3-diynes for the synthesis of 3-alkynylated isoquinolone derivatives. Our calculations reveal a redox-neutral pathway for the annulation reaction. The stepwise analysis of the reaction channels indicates the migratory insertion step and the concerted reductive elimination/oxidative addition of the Ru(p-cymene) moiety to form the N-C bond leading to the 3-alkynylated product to be the selectivity- and rate-determining steps, respectively. Finally, the distortion/interaction analysis using the activation-strain model suggests the steric effect as the determining factor for the observed regioselectivity for the formation of the 3-alkynylated product. Overall, the computationally obtained key insights into the catalytic mechanism and the origin of regioselectivity in the C-H activation/annulation reaction can be used as a guide to rationally design and develop novel transformation strategies for heterocycle synthesis.

Cr3+‐doped far‐red phosphors with zero thermal quenching and excellent spectral matching for plant lighting application

AbstractFar‐red‐emitting (700−740 nm) phosphors are essential for the fabrication of plant lighting phosphor‐converted light‐emitting diodes (pc‐LEDs). However, the development of highly efficient, thermally stable, and spectrally matched far‐red phosphors still remains a challenge. Herein, far‐red GdAlO3:Cr3+ (GAO:Cr3+) phosphors were synthesized via solid‐state reaction and investigated for plant lighting pc‐LED applications. A low‐temperature flux‐assisted synthesis strategy was adopted to improve the crystalline quality, suppress the defect formation, and maintain the valence state of Cr3+ in the phosphors, finally leading to significant luminescent enhancement (∼10 times). The GAO:Cr3+ phosphors show the 2E sharp‐line emissions around 730 nm, which is highly matched with the far‐red absorption band of plants. The optimized GAO:0.01Cr3+ phosphor exhibits a high internal quantum efficiency of 98.3% and zero thermal quenching even up to 250°C. The fabricated pc‐LED can generate an overall output power of 78.1 mW at 100 mA drive current, with a high energy conversion efficiency of 25.3%. The findings demonstrate the great potential of GAO:Cr3+ as far‐red‐emitting phosphor materials for plant growth pc‐LED applications.

One‐step Synthesis of Organic Terminal 2D Ti3C2Tx MXene Nanosheets by Etching of Ti3AlC2 in an Organic Lewis Acid Solvent

AbstractThe surface and interface chemistry are critical for controlling the properties of two‐dimensional transition metal carbides and nitrides (MXenes). Numerous efforts have been devoted to the functionalization of MXenes with small inorganic ligands; however, few etching methods have been reported on the direct bonding of organic groups to MXene surfaces. In this work, we demonstrated an efficient and rapid strategy for the direct synthesis of 2D Ti3C2Tx MXene nanosheets with organic terminal groups in an organic Lewis acid (trifluoromethanesulfonic acid) solvent, without introducing additional intercalations. The dissolution of aluminum and the subsequent in situ introduction of trifluoromethanesulfonic acid resulted in the extraction of Ti3C2Tx MXene (T=CF3SO3−) (denoted as CF3SO3H−Ti3C2Tx) flakes with sizes reaching 15 μm and high productivity (over 70 %) of monolayers or few layers. More importantly, the large CF3SO3H−Ti3C2Tx MXene nanosheets had high colloidal stability, making them promising as efficient electrocatalysts for the hydrogen evolution reaction.

Stabilizing Few‐Atom Platinum Clusters by Zinc Single‐Atom‐Glue for Efficient Anti‐Markovnikov Alkene Hydrosilylation

Few‐atom metal clusters (FAMCs) exhibit superior performance in catalyzing complex molecular transformations due to their special spatial environments and electronic states, compared to single‐atom catalysts (SACs). However, achieving the efficient and accurate synthesis of FAMCs while avoiding the formation of other species, such as nanoparticles and SACs, still remains challenges. Herein, we report a two‐step strategy for synthesis of few‐atom platinum (Pt) clusters by predeposition of zinc single‐atom‐glue (Zn1) on MgO nanosheets (Ptn‐Zn1/MgO), where FAMCs can be obtained over a wide range of Pt contents (0.09 to 1.45 wt%). Zn atoms can act as Lewis acidic sites to allow electron transfer between Zn and Pt through bridging O atoms, which play a crucial role in the formation and stabilization of few‐atom Pt clusters. Ptn‐Zn1/MgO exhibited a high selectivity of 93% for anti‐Markovnikov alkene hydrosilylation. Moreover, an excellent activity with a turnover frequency of up to 1.6 ×104 h−1 can be achieved, exceeding most of the reported Pt SACs. Further theoretical studies revealed that the Pt atoms in Ptn‐Zn1/MgO possess moderate steric hindrance, which enables high selectivity and activity for hydrosilylation. This work presents some guidelines for utilizing atomic‐scale species to increase the synthesis efficiency and precision of FAMCs.

Stabilizing Few-Atom PlatinumClusters by ZincSingle-Atom-Glue for Efficient Anti-Markovnikov Alkene Hydrosilylation.

Few-atom metal clusters (FAMCs) exhibit superior performance in catalyzing complex molecular transformations due to their special spatial environments and electronic states, compared to single-atom catalysts (SACs). However, achieving the efficient and accurate synthesis of FAMCs while avoiding the formation of other species, such as nanoparticles and SACs, still remains challenges. Herein, we report a two-step strategy for synthesis of few-atom platinum (Pt) clusters by predeposition of zincsingle-atom-glue (Zn1) on MgO nanosheets (Ptn-Zn1/MgO), where FAMCs can be obtained over a wide range of Pt contents (0.09 to 1.45 wt%). Zn atoms can act as Lewis acidic sites to allow electron transfer between Zn and Pt through bridging O atoms, which play a crucial role in the formation and stabilization of few-atom Pt clusters. Ptn-Zn1/MgO exhibited a high selectivity of 93% for anti-Markovnikov alkene hydrosilylation. Moreover, an excellent activity with a turnover frequency of up to 1.6 ×104 h-1 can be achieved, exceeding most of the reported Pt SACs. Further theoretical studies revealed that the Pt atoms in Ptn-Zn1/MgO possess moderate steric hindrance, which enables high selectivity and activity for hydrosilylation. This work presents some guidelines for utilizing atomic-scale species to increase the synthesis efficiency and precision of FAMCs.

Utilizing a Carbazole‐Incorporated Regioisomeric Synthesis Strategy to Design Hole Transporting Materials for Perovskite Solar Cells

Two new p‐type molecules, namely TAT‐TY3 and TAT‐TY4, featuring triazatruxene endcaps and carbazole π‐bridges, were synthesized. The photophysical and electrochemical properties of synthesized materials were comparatively investigated based on their 2,7‐ and 3,6‐carbazole conjugation pathways. Optical characterizations revealed the impact of non‐bonding electron delocalization of triazatruxene through carbazole moieties, resulting in a significant increase in absorption intensity corresponding to n‐π* energy transitions and a red shift of triazatruxene moieties. Consequently, the optical band gaps of TAT‐TY3 and TAT‐TY4 were measured at 3.0 and 3.2 eV, respectively. Moreover, the molecules' first oxidation potentials exhibited a drastic difference due to the electrochemical behavior of 2,7‐ and 3,6‐carbazole moieties. The highest occupied molecular orbital (HOMO) level for TAT‐TY3 was measured to be ‐5.02 eV, while for TAT‐TY4, it was measured as ‐4.67 eV. Hole‐extraction properties were explored using steady‐state and time‐resolved photoluminescence spectroscopy, revealing enhanced charge transfer between the TAT‐TY3/Perovskite interface due to the better alignment of HOMO energy levels. The photovoltaic performances of the hole‐transporting materials (HTMs) were successfully characterized in triple‐cation perovskite solar cells and efficiencies of up to 17.9%, 16.2%, and 9.8% were achieved for Spiro‐OMeTAD, TAT‐TY3, and TAT‐TY4, respectively.

Synergistic strategy of surface-induced spinel structure and F doping to improve the electrochemical performance of Li-rich cathodes

Li-rich Mn-based materials provide higher capacity than commercial NCM layered materials due to the synergistic redox effect of cations and anions. However, lattice straining and structural collapse caused by the irreversible oxygen release at high voltage range during cycling, which results in severe capacity and voltage decay. Herein, a synergistic strategy of surface-induced spinel structure and F doping is provided to improve the structural stability. The surface spinel structure helps to reduce the structural collapse caused by electrolyte corrosion on the cathode and effectively inhibits voltage decay resulted from structural evolution. The stronger Mn-F bonds are formed by F doping to inhibit migration of transition metal (TM) and induce the uniform deposition of LiF to form the thinner and more stable CEI on the cathode. Accordingly, the designed cathode (LMNO-NF) shows remarkable cycling performance with the capacity retention of 86.68 ​% and voltage retention of 96.6 ​% for 200 cycles at 1C, higher than pristine material (68.76 ​% and 85.75 ​%). Therefore, this simple dual-modification strategy of one-step synthesis is promising for solving the structural evolution and voltage decay of Li-rich Mn-based cathode materials effectively, achieving further commercialization.

Exploring the role of surface and porosity in CO2 capture by CaO-based adsorbents through response surface methodology (RSM) and artificial neural networks (ANN)

In this study, synthetic CaCO3 materials were utilized as precursors for CaO-based CO2 sorbents. The investigation examined how various operating parameters—such as synthesis temperature (ST), stirring rate (SR), and surfactant percentage (SP)—impact the properties of the adsorbents. Samples were firstly characterized by X-ray diffraction and Scanning Electron Microscopy (SEM), which revealed that the prevalence of calcite or aragonite crystal phases in the synthetic CaCO3 precursors can be tuned by adequately choosing the dose of surfactant (Triton-X100®), so that it can be used as a crystal habit and growth modifier. The calcination process applied to the CaCO3 precursors leads to the formation of partially sinterized cubic crystals of CaO, accompanied by minor quantities (< 5 %) of additional compounds like Ca(OH)2 or CaSO4. Specific surface area (SBET) and porosity were determined by measuring the N2 adsorption isotherms. A CaCO3 sample with an unprecedented value of SBET as large as 116 m2/g was prepared operating under optimal conditions. SBET and pore volumes were successfully correlated with the CO2 uptake capacity of the samples. SBET is more influential for experiments carried out under diluted CO2 atmosphere. When pure CO2 is used, the influence of meso- and micropore volumes (Vme and Vmi) is clearly predominant, which suggests that in this latter case diffusion through the porous texture of the samples plays a more remarkable role. A double-way approach through Response Surface Methodology (RSM) and the use of Artificial Neural Networks (ANNs) has been used to analyze the CO2 uptake capacity of the samples. Within the operational interval, excellent results were obtained for pure and diluted CO2 flow, and RSM and ANNs have demonstrated to be a very efficient tool to correlate the behavior of the CaO-based materials as CO2 sorbents with the surface area and pore volumes of the samples. Valuable information on (i) the importance of the different factors under study; (ii) their influence on the surface and porosity of the CaO-derived sorbents; and (iii) the subsequent CO2 capture performance of the sorbents has been obtained. The results suggest that four parameters have a statistically significant influence on CO2 uptake. These parameters are SR, the square of SR, its interaction with SP, and the square of SP. Additionally, the study assessed the stability of the CaO-based sorbents over 11 consecutive calcination-carbonation cycles. By adequately choosing the synthesis strategy and conditions, an almost negligible shrinkage effect can be achieved, resulting in a more sustained uptake capacity throughout the cycles.

Functionalization Ti3C2Tx as highly sensitive and selective SERS substrate by reduction rapid synthesis strategy

Functionalization Ti3C2Tx as highly sensitive and selective SERS substrate by reduction rapid synthesis strategy

Isolation, characterization, identification and quantification of 6-F oxyphenisatin dipropionate, a novel illegal additive, from a fruit-flavored jelly.

This study is aimed to screen, identify and detect illegal additives from healthcare products which claim or imply to have weight-loss effects. Ultra-high performance liquid chromatography-quadruple-time-of-flight mass spectroscopy (UPLC-Q-TOF/MS) was employed to perform non-targeted screening of illegal additives from a total of 26 batches of healthcare products with weight-loss effects. A novel oxyphenisatin dipropionate analog was discovered in a fruit-flavored jelly that was not clearly labeled as containing added drugs. After being separated and purified by silica gel column chromatography, the analog was unambiguously characterized by one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) spectroscopies. The molecular structure of the analog was finally identified by comparing the spectra of the analog with those of suspected candidates prepared by de novo synthesis strategy. Thereafter, a sensitive and precise reversed phase ultra performance liquid chromatography coupled with photodiode array (UPLC-PDA) detection method was developed and verified for the determination of the analog in 15 batches of real samples. In the MS/MS spectra, the signal intensity of mass/charge ratios (m/z, 242 and 214) of the novel analog fragments was highly similar to that of mass/charge ratios (m/z, 224 and 196) of oxyphenisatin dipropionate fragments. Additionally, the 1D NMR spectrum of the analog was completely consistent with that of one of the suspected candidates prepared by the de novo synthesis strategy. Based on the above analysis, the structure of the analog was determined as 3,3-bis[4'-(propionyloxy)phenyl]-6-fluoro-2-oxoindoline, which was briefly named 6-F oxyphenisatin dipropionate. A developed quantitative method showed good linearity (R2>0.999) in a concentration range of 1.0-100μg/mL. The limits of detection (LOD) and quantification (LOQ) for the analog was 3mg/kg and 10mg/kg, respectively. The average recoveries of the analog from spiked three different matrix samples in low (1 time of LOQ), medium (2 times of LOQ), and high (10 times of LOQ) concentrations were varied from 93.9% to 107.8% with a precision of 0.03-1.56%. Results of quantitative analysis in 15 batches of healthcare products revealed that the content of 6-F oxyphenisatin dipropionate in a fruit-flavored jelly and a solid beverage was 118mg/kg and 330mg/kg, respectively. In terms of its structure, 6-F oxyphenisatin dipropionate replaces hydrogen atom by the fluorine atom at position 6 on the indolinone fragment in oxyphenisatin dipropionate. To our best knowledge, 6-F oxyphenisatin dipropionate has never been detected as an illegal additive in foods. Such illegal addition of the analog to foods is more concealing, thus the supervision and testing departments should attach great importance to its application in food markets.

Palladium(II)-catalyzed annulation of N-methoxy amides and arynes: computational mechanistic insights and substituents effects.

The combined use of transition metal-catalyzed C-H activation with aryne annulation reactions has emerged as an important strategy in organic synthesis. In this study, the mechanisms of the palladium(II)-catalyzed annulation reaction of N-methoxy amides and arynes were computationally investigated by density functional theory. The role of methoxy amide as a directing group was elucidated through the calculation of three different pathways for the C-H activation step, showing that the pathway where amide nitrogen acts as a directing group is preferable. At the reductive elimination transition state, an unstable seven-membered ring is formed preventing the lactam formation. A substituent effect study based on an NBO analysis, Hammet, and using a More O'Ferall-Jenks plot indicates that the C-H activation step proceeds via an electrophilic concerted metalation-deprotonation (eCMD) mechanism. The results show that electron-withdrawing groups increase the activation barrier and contribute to an early Pd-C bond formation and a late C-H bond breaking when compared with electron-donating substituents. Our computational results are in agreement with the experimental data provided in the literature. All calculations were performed using Gaussian 16 software. Geometry optimizations, frequency analyses at 393.15 K, and IRC calculations were conducted at the M06L/Def2-SVP level of theory. Corrected electronic energies, NBO charges, and Wiberg bond indexes were computed at the M06L/Def2-TZVP//M06L/Def2-SVP level of theory. Implicit solvent effects were considered in all calculations using the SMD model, with acetonitrile employed as the solvent.

Covalent triazine framework-based porous mixed matrix membranes for highly efficient dye/salt separation

Mixed matrix membranes (MMMs) incorporating porous covalent organic frameworks (COFs) as fillers have garnered significant attention in membrane separation for water purification. Covalent triazine frameworks (CTFs) possess high thermochemical stability, an inherent triazine conjugate structure, and tunable pore size. Despite these attributes, CTFs have been underutilized in MMMs. In this study, CTF-based porous MMMs were fabricated by blending 4,4′-biphenyldicarbonitrile (BPCN) monomer with polyacrylonitrile (PAN) and employing titanium dioxide nanoparticles (TiO2 NPs) as a pore-forming agent. The nature of PAN also makes the mixed matrix membranes have better hydrophilicity and mechanical properties. The optimized CTF-MMM exhibited an impressive water permeance of ∼ 204 L m−2 h−1 bar−1, accompanied by a remarkable dye rejection of ∼ 99 % and a low salt rejection. Moreover, the CTF-MMM demonstrated sustained water permeance and separation performance even after 48 h. This work introduces a synthesis strategy for fabricating high-performance CTF-based porous mixed matrix membranes, showcasing significant potential for applications in dye/salt separation.

Copper Phenylacetylide and TiO2 Modification for an Efficient Visible-Light-Driven Oxidative Coupling of Amines.

The selective oxidation of amines to imines under mild conditions has attracted much attention. Our study reveals that copper phenylacetylide (PhC2Cu) could serve as an efficient photocatalyst for imine synthesis under visible-light irradiation (>400 nm). Utilizing benzylamine as a model reactant, PhC2Cu achieves an imine yield of 50.4%, which is 5 times higher than that of P25 under the same conditions and comparable to the yield obtained by the 3 wt % Au/P25 photocatalyst (55.4%). Further loading 3.9 nm TiO2 onto PhC2Cu through tetrabutyl titanate hydrolysis increases the imine yield to 84.7%, with a Ti:Cu atomic ratio of 3.65%. Control experiments, photoluminescence (PL) spectra, optical pump terahertz probe (OPTP) spectra, and electron spin resonance (ESR) tests confirm that the optimized TiO2 modification promotes the separation of excited carriers and electron transfer in PhC2Cu and facilitates the activation of surface oxygen, thereby enhancing the formation of superoxide radicals, a key active oxygen species in the reaction system. This work presents a promising strategy for efficient imine synthesis via amine coupling and expands the application field of PhC2Cu-based photocatalysts.

Synthesis of natural oxygen-doped bamboo-derived hierarchical micro-mesoporous composite carbon materials using a green activation strategy

Utilizing biomass waste to synthesize hierarchical micro-mesoporous composite carbon materials for application in the field of supercapacitors realized green and sustainable energy development. This paper efficiently synthesized natural O-doped carbon materials using bamboo as biomass material by simple air pre-oxidation and secondary carbonization methods. Among them, KCl acted as a recyclable templating agent and flame retardant, facilitating the construction of mesoporous structures. The green activator CH3COOK promoted the generation of micropores. The combination of dual activation strategies (physical and chemical) contributed to the conversion of bamboo to hierarchical micro-mesoporous composite carbon materials. During pre-carbonization, air was used as a natural dopant which etched the carbon material and promoted the creation of oxygenated functional groups. The best carbon material exhibited an excellent electrochemical capacity of 321.65 F/g in 6 M KOH electrolyte. Furthermore, the symmetric supercapacitor exhibited high cycling stability (95.52 %) and outstanding power density. This work provided a new idea for preparing controllable biomass-derived carbon materials, while offering a reference for applying dual activation strategies in carbon material synthesis.

Trinitromethyl-Substituted 1H-1,2,4-Triazole Bridging Nitropyrazole: A Strategy of Utterly Manipulable Nitration Achieving High-Energy Density Material.

Nitro groups have been demonstrated to play a decisive role in the development of the most powerful known energetic materials. Two trinitromethyl-substituted 1H-1,2,4-triazole bridging nitropyrazoles were first synthesized by straightforward routes and were characterized by chemical (MS, NMR, IR spectroscopy, and single-crystal X-ray diffraction) and experimental analysis (sensitivity toward friction, impact, and differential scanning calorimetry-thermogravimetric analysis test). Their detonation properties (detonation pressure, detonation velocity, etc.) were predicted by the EXPLO5 package based on the crystal density and calculated heat of formation with Gaussian 09. These new trinitromethyl triazoles were found to show suitable sensitivities, high density, and highly positive heat of formation. The combination of exceedingly high performances superior to those of HMX (1,3,5,7-tetranitrotetraazacyclooctane), and its straightforward preparation highlights compound 8 as a promising high-energy density material (HEDM). This work supports the effectivity of utterly manipulable nitration and provides a generalizable design synthesis strategy for developing new HEDMs.

A Versatile Strategy for the Controlled Synthesis of Atomically Precise Palladium Nanoclusters.

The study of the structures, applications, and structure-property relationships of atomically precise metal nanoclusters relies heavily on their controlled synthesis. Although great progress has been made in the controlled synthesis of Group 11 (Cu, Ag, Au) metal nanoclusters, the preparation of Pd nanoclusters remains a grand challenge. Herein, a new, simple, and versatile synthetic strategy for the controlled synthesis of Pd nanoclusters is reported with tailorable structures and functions. The synthesis strategy involves the controllable transformations of Pd4(CO)4(CH3COO)4 in air, allowing the discovery of a family of Pd nanoclusters with well-defined structure and high yield. For example, by treating the Pd4(CO)4(CH3COO)4 with 2,2-dipyridine ligands, two clusters of Pd4 and Pd10 whose metal framework describes the growth of vertex-sharing tetrahedra have been selectively isolated. Interestingly, chiral Pd4 nanoclusters can be gained by virtue of customized chiral pyridine-imine ligands, thus representing a pioneering example to shed light on the hierarchical chiral nanostructures of Pd. This synthetic methodology also tolerates a wide variety of ligands and affords phosphine-ligated Pd nanoclusters in a simple way. It is believed that the successful exploration of the synthetic strategy would simulate the research enthusiasm on both the synthesis and application of atomically precise Pd nanoclusters.