Electronegative Atoms Research Articles

Insights through molecular modeling into the structural requirement of Phenyl(6-phenylpyrazin-2-yl)methanone derivatives as aldose reductase inhibitors

Aldose reductase, play an important role in the pathogenesis of diabetic complications such as neuropathy, nephropathy and retinopathy. Therefore design of aldose reductase inhibitors has received considerable attention. In the present study molecular insights were explored through docking and QSAR. The quantification of the structural features of Phenyl(6-phenylpyrazin-2-yl)methanone analogs inferred that atomic Senderson electronegativity, van der Waals volume and charge distribution on the molecule are decisive for the aldose reductase inhibitory activity. Moreover, docking study depicted that benzonoid system of scaffold is crucial for - interaction with the side chain of key aromatic amino acids i.e. TRP111 and TRP20. These structural insights might provide significant roadmap for continuing search of potential ARIs prior to synthesis.

B─C Bonding Configuration Manipulation Strategy Toward Synergistic Optimization of Polarization Loss and Conductive Loss for Highly Efficient Electromagnetic Wave Absorption

AbstractIn non‐metallic atom‐doped carbonaceous materials, the disparity in electronegativity between the doped constituents and carbon atoms predetermines the bonding topology of covalent bonds and the distribution of electron density. This, consequently, influences the polarization and electron transport behavior within the doped domain and the electromagnetic wave attenuation attributes of the carbonaceous material. However, the influence of covalent bonds formed by doping with weakly electronegative atoms on electron density distribution, polarization effects, and electromagnetic wave attenuation remains uncharted. To address this deficiency, this study fabricates a porous carbonaceous material (NCP) and incorporates boron‐doped atoms to form a material with tunable B─C bonding configurations (B‐NCP). By modulating the B─C bonding configuration and proportion, it is feasible to achieve the synergistic optimization of conductive loss and polarization loss of the B‐NCP specimen. The optimized prototype B‐NCP‐1200 sample displays exceptionally efficient electromagnetic wave absorption capabilities with a minimum reflection loss (RLmin) of −52.03 dB and an effective absorption bandwidth (EAB) of 5.36 GHz. This study presents a conscientious model for comprehending the electromagnetic attenuation mechanisms associated with weakly electronegative atom doping in carbon‐based electromagnetic wave‐absorbing materials.

Quantitative Structure Activity Relationship Analysis of Benzimidazole Derivatives as Aldose Reductase Inhibitors

Hyperglycemia is involved in the pathogenesis of diabetic neuropathy, retinopathy, nephropathy, and macro-vascular disease via multiple mechanisms, of which increased aldose reductase activity. Aldose reductase inhibitors, when administered from the onset of hyperglycemia, prevent the progression of polyol accumulation–linked complication. In this work, we report quantitative structure activity relationship analysis performed on the Triazino[4,3-α]benzimidazole acetic acid derivatives as aldose reductase inhibitors. The molecular modeling study was performed by using the software BioMed CAChe 6.0 and the regression analysis by SYSTAT 10.2. Various physicochemical parameters belonging to different classes viz. hydrophobic, steric and electronic etc. were calculated. QSAR models were generated using 17 compounds. The model showed a good correlative and predictive ability having convention coefficient (r2) of 0.846 and cross-validated correlation coefficient (q2) of 0.6866 by LOO external validation method. Based on the developed QSAR model, it may be concluded that aldose reductase inhibition activity of benzimidazole acetic acid derivatives is strongly influenced by the thermodynamic and electronic nature of the substituents. QSAR model shows that LOGP, LUMO energy, and steric energy are negatively affecting the biological activity. For a molecule to have higher aldose reductase activity, compound should be less lipophilic and should have more electronegative groups or atoms than electropositive groups or atoms present in the compound.

Computational detangling chalcogen elements substitutions associated ESDPT mechanism for oxazolinyl-substituted hydroxyfluorene derivatives

In view of the distinguished photochemical and photobiological characteristics of oxazolinyl-substituted hydroxyfluorene and its derivatives, herein, we mainly focus on probing into excited state behaviors of the novel 9,9-dimethyl-3,6-dihydroxy-2,7-bis(4,5-dihydro-4,4-dimethyl-2-oxazolyl) fluorene (Oxa-OH) derivatives. In light of the significant effects resulting from substituting oxygen elements, three Oxa-OH derivatives (i.e., Oxa-OO, Oxa-SS and Oxa-SeSe fluorophores) are considered in this work. For these three different fluorophores, we detangle the effects of atomic electronegativity and charge recombination related to oxygen elements in excited state double proton transfer (ESDPT) processes. Because of the low potential energy barriers, we confirm the ESDPT happens by the sequential type. Based on heterosubstituted Oxa-OS and Oxa-OSe compounds, we further verify the chalcogen atomic-electronegativity-regulated stepwise ESDPT mechanism. We sincerely wish our work could provide a theoretical reference for proving this novel mechanism of ESDPT experimentally.

A theoretical exploration of the influence of oxygen element on photo-induced behaviours for flavonoid derivatives with Me2N substitution

The exceptional properties of flavonoid derivatives are a great inspiration for our research. In the fields of medicine and chemistry, flavonoids present the superior ability to enhance non-specific immune function and humoral immune response. Herein, our primary focus lies in the theoretical exploration of the photo-induced characteristics exhibited by the novel Me2N-substituted flavonoid (MEF) fluorophore. Considering the potential photo-induced properties associated with chalcogen atomic electronegativity in photoexcitation, using density functional theory (DFT) and time-dependent DFT (TDDFT) methods, we primarily pay attention to probing into photo-induced hydrogen bonding effects and concomitant charge reorganisation processes. Given changes in chemical geometries and the infrared (IR) vibrational shifts of three MEF derivatives (MEF-O, MEF-S and MEF-Se), we confirm that intramolecular hydrogen bonding should be strengthened by facilitating excited state intramolecular proton transfer (ESIPT) reactions. Particularly, the redistribution of charge further shows the ESIPT behaviour. By constructing potential energy curves (PECs) and identifying transitional reaction state (TS) structures, we ultimately validate the electronegativity-dependent ESIPT mechanisms of chalcogen elements in MEF derivatives. We sincerely hope that our work can accelerate future development and applications of flavonoid derivatives.

1,4-Bis(pyridin-1-ium)benzene trifluoroacetate coordinated to chloropropyl functionalized SiO2-nano-NiFe2O4 (BPBTCSF): As a novel and effectual mesoporous bi-functional magnetic catalyst for the synthesis pyrido[2,3-d:6,5-d']dipyrimidines

Here in, we report the synthesis of 1,4-Bis(pyridin-1-ium)benzene trifluoroacetate coordinated to chloropropyl functionalized SiO2-nano-NiFe2O4 (BPBTCSF). Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), elemental mapping analysis, Brunauer-Emmett-Teller (BET), thermal gravimetric analysis (TGA), vibrating-sample magnetometry (VSM) and X-ray diffraction (XRD) techniques characterized the framework of this catalyst. The catalytic activity of this nano-composite was then examined in the one-pot four-component reaction of 2-thiobarbituric acid, NH4OAc, and aldehyde for synthesis of pyrido[2,3-d:6,5-d']dipyrimidines under optimal conditions (5 mg of BPBTCSF, H2O, 25 °C). BPBTCSF exhibits benefits as a heterogeneous catalyst, such as exciting performance in the production of derivatives (2 to 5 min, 90 % to 98 %), six times reproducibility with a slight decrease in catalytic activity, the simultaneous presence of acidic and basic sites (Hydrogen attached to the electronegative nitrogen atom and CF3COOˉ, respectively), convenient purification and separation from the reaction mixture.

The molecular structure, electronic properties, and decomposition mechanism of FOX-7 under external electric field were calculated based on density functional theory.

Based on the density functional theory (DFT), we analyzed the changes of the FOX-7 molecule under external electric field (EEF) from multiple perspectives, including molecular structure, electronic structure, decomposition mechanism, frontier molecular orbitals (FMOs), and density of states (DOS). The results revealed that as the intensity of the positive EEF increased, the detonation performance of the FOX-7 molecule was significantly enhanced, while its thermal stability was also improved. This discovery challenges the traditional concept that explosives are inherently dangerous under external electric fields and provides new insights for research in related fields. To further explore the impact of EEF on the thermal stability of FOX-7, we conducted a thorough analysis of the mechanism by which EEF affects the decomposition process. Our findings indicate that applying a positive EEF significantly increases the energy required to overcome intramolecular hydrogen transfer and C-NO2 bond rupture, while having a relatively minor effect on the nitro isomerization process. This observation further demonstrates that the appropriate application of a positive EEF can enhance the detonation performance of FOX-7 without compromising its thermal stability. Further research revealed that as the intensity of the positive EEF increased, the electronegativity of the nitro group gradually enhanced, leading to an increase in the electronegativity of the oxygen atoms within it. This made the oxygen atoms more prone to participating in chemical reactions. This phenomenon also explains why the energy barrier required for nitro isomerization in FOX-7 gradually decreases as the intensity of the positive EEF increases. Based on the density functional theory (DFT), the structural optimizations were performed both under applied EEF and without EEF at the B3LYP/6-311G (d, p) level. All optimized results were converged and exhibited no imaginary frequencies. Based on the optimized structures, single-point energy calculations were further conducted at the B3LYP/def2-TZVPP level. Subsequently, analyses of molecular structure, electronic structure, decomposition mechanism, frontier molecular orbitals, and density of states were carried out.

Impact of molecular structure on the biological removal efficiency of fluoroquinolone antibiotics: An in-silico approach

Fluoroquinolone antibiotics (FQs), one of the most widely used antibacterials, have been recognized as emerging contaminants with adverse human health concerns. To overcome the adverse effects, a theoretical molecular design and screening approach was developed in this study to improve the removal efficiency of FQs by Chlorella in artificial or natural wetland systems. Among the 189 designed norfloxacin (NOR) derivatives, NOR-140 was screened with significantly improved biosorption, bioaccumulation, and biodegradation removal and functional effects, and reduced human health and ecological risks. The removal mechanism NOR-140 was also analyzed using adsorption kinetics, molecular docking, molecular dynamics simulations and machine learning models. Protein and polysaccharide structures play a major role in the adsorption process, polarizability and molecular volume of NOR-140 affect the bioaccumulation ability, and hydrogen bonding was found as the key force promoting the degradation ability of NOR-140. Modifying specific sites (5, 8, and 13) with functional groups containing highly electronegative atoms (O, F) significantly enhances the biodegradability of FQs alternatives by Chlorella. This study provided theoretical support for designing environmentally friendly FQs alternatives with improved degradation ability and advanced the understanding of how the FQs' molecular structures affect its removal by Chlorella.

DFT molecular modeling investigation and optical properties characterization of CR-39 films

Abstract In this study, the structural and optical characteristics of CR-39 films were investigated both theoretically and experimentally. A number of parameters for the CR-39 structure were theoretically computed by the density functional theory (DFT) method at B3LYP/6–311 G (p, d) level of theory. FTIR and UV/Vis spectroscopy were used to determine the structure compositions and the optical parameters of the CR39 film, respectively. The computed and experimental findings show good concordance. It was found that the CR-39 compound’s total energy, dipole moment, and energy difference between the LUMO and HOMO were, respectively, −994.575 a.u., 2.772 Debye, and 7.045 eV. The MEP showed a progressive change in color, with blue signifying a low electron density and red denoting a high electron density linked to nucleophilic reactivity and electrophilic reactivity. Further, the positive charges on all hydrogen atoms, which range from 0.16506 to 0.22032 a.u., imply that they are acceptors. The positive H34 is strongly produced when electrons from the negatively charged C17 are taken up. Because they are donor atoms, part of the carbon atoms in the structure is negative, while the other atoms are positive. The highest electronegative atoms H23 and H24 were substituted, resulting in the extremely negative carbon atom C7 (−0.32436). According to the experimentally determined absorption coefficient and energy gap values, CR-39 films may find application in optoelectronic devices.

Tactfully regulating the ESIPT mechanism of novel benzazolyl-4-quinolones fluorophore by atomic electronegativity

The effects of atomic electronegativity (O, S and Se) on the excited state intramolecular proton transfer (ESIPT) behavior of fluorescent benzazolyl-4-quinolones derivatives have been investigated theoretically. Analysis of structure parameters and infrared vibrational spectra indicate that the intramolecular hydrogen bonds (O1H1⋯N1) are gradually strengthened in the first (S1) excited state as the atomic electronegativity diminishes (O → S → Se). The topological parameters, reduced density gradient (RDG) scatter plots and interaction region indicator (IRI) isosurface further confirm our results. The energy gap of molecular orbitals reflect that the less atomic electronegativity prompt greater excited state reactivity. In addition, the constructed potential energy curves (PECs) reveal that Se substituent has lower potential barrier (0.42 kcal/mol), which is more likely to accelerate the occurrence of ESIPT process. These results show that the atomic electronegativity helps to regulate the ESIPT process, which will pave the way for the design and synthesis of ESIPT-based fluorophores in future.

Functionalized Quasi-Solid-State Electrolytes in Aqueous Zn-Ion Batteries for Flexible Devices: Challenges and Strategies.

The rapid development of wearable and intelligent flexible devices has posed strict requirements for power sources, including excellent mechanical strength, inherent safety, high energy density, and eco-friendliness. Zn-ion batteries with aqueous quasi-solid-state electrolytes (AQSSEs) with various functional groups that contain electronegative atoms (O/N/F) with tunable electron accumulation states are considered as a promising candidate to power the flexible devices and tremendous progress has been achieved in this prospering area. Herein, this review proposes a comprehensive summary of the recent achievements using the AQSSE in flexible devices by focusing on the significance of different functional groups. The fundamentals and challenges of the ZIBs are introduced from a chemical view in the first place. Then, the mechanism behind the stabilization of the flexible ZIBs with the functionalized AQSSE is summarized and explained in detail. Then the recent progress regarding the enhanced electrochemical stability of the ZIBs with the AQSSE is summarized and classified based on the functional groups on the polymer chain. The advanced characterization methods for the AQSSE are briefly introduced in the following sections. Last but not least, current challenges and future perspectives for this promising area are provided from the authors' point of view.

Understanding Cation-Anion Ionic Bonding in Tetramethylammonium Salts: Insights from Density Functional Theory and X-ray Crystallography.

In describing the charge on tetraalkylammonium ions, a charge of +1 is usually assigned. This is both the actual charge as well as the "formal charge" which is usually written on the nitrogen atom to indicate the electron deficiency experienced by the nitrogen atom relative to the valence electrons. Nitrogen is the most electronegative atom in the ion. The results in this study show that despite the convention of writing the positive charge on nitrogen, the ion is polarized through the σ bond framework to present four tetrahedral faces, each having close to a full charge of +1 to any anionic species which approach the cation.

Exploring the impact of Anions, Alkyl group and confinement effect in ionic liquid @ UiO-66(Zr) MOF: A DFT study

Metal organic frameworks (MOFs) have emerged as a strong research material due to their exceptional porosity and tunable functional nature. MOF structures consist of metal nodes with organic linker, which can be functionalized depending on the required application. With the tunable properties, it has wide range of applications in energy, environmental and therapeutic approaches. Nevertheless there are several factors which can affect their performance such as lower affinity towards target molecules, chemical and thermal stability etc. To counter these issues several studies have been devoted on functionalizing the MOF. In this work, we have considered UiO-66 (University of Oslo-66) MOF because of its exceptional thermal and chemical stability with a series of versatile ionic liquids (ILs). The selected ILs are 1-ethyl-3-methylimidazolium ([C2MIm]+) and 1‑butyl‑3-methylimidazolium ([C4MIm]+) cations with various anions [X]−, where X = acetate (OAc), tetrafluroborate (BF4), dicyanamide (DCA), nitrite (NO2) and chloride (Cl) anions. These ILs have been impregnated in tetrahedral (∼10 Å) and octahedral (∼16 Å) pores of UiO-66 structure. First principle density functional theory (DFT) approach is used to study the structure, stability, spectral properties and charge transfer between IL/UiO-66 interfaces. Our calculations suggest that, IL does not affect the structure of UiO-66 surface. The anion and the alkyl group in the cations play a vital role in the stability of the complexes. Furthermore, confinement effect influence the stability of the complexes, irrespective nature of anion and cation. Electron density and charge transfer analyses reveal that anions have profound liking towards MOF because of having high electronegative atoms. Our study will help to understand the molecular level interaction between IL@MOF interface, and these composite can be utilized for the energy and environment related applications.

Electronegativity Effects on Conformational Stability Using Bent's Rule: From Simple Molecules to Acetylcholine

Hybridization and electronegativity are fundamental concepts in chemistry connected by Bent's rule. This rule explains many aspects of the structural chemistry and reactivity of organic and inorganic compounds. Over decades, the application of Bent's rule has expanded, demonstrating its wide-ranging utility in elucidating molecular stability due to the substitution of highly electronegative atoms. This study successfully leverages Bent's rule to explain conformational energy difference in acetylcholine case using density-functional calculations. We used butane (Group 2) and butanone (Group 3) families to model the head of ACh+ and substituted one of the carbons with highly electronegative atoms: B, C, N, and O. This enabled us to evaluate the effects of electronegativity, as well as the presence of carbonyl groups, on their conformational stability and s character. There were three highlighted results. First, our calculations result in the s character are consistent with Bent's rule. Second, the high conformational energy differences can be attributed to the changes of s character in C2–Z bond: linear in Group 2 and exponential in Group 3, indicating the strong contribution of the carbonyl group. Third, the key determining factor in ACh+ conformational stability is the carbonyl group, which also strongly contributes to the solute-solvent interactions. Therefore, our study can be further applied to other similar molecules, potentially leading to broader applications in chemistry, especially for understanding ACh+ stability for Alzheimer’s Disease treatment.

Theoretical Investigation on Proton Transfer Directionality and Dynamics Behavior of 3-(Benzo[d]thiazol-2-yl)-2-hydroxy-5-methoxybenzaldehyde with Two Asymmetric Proton Acceptors.

A detailed theoretical investigation on the excited state intramolecular proton transfer (ESIPT) directionality and dynamics behavior of 3-(benzo[d]thiazol-2-yl)-2-hydroxy-5-methoxybenzaldehyde (BTHMB) with two unsymmetric proton acceptors (N and O2) has been performed. The hydrogen bond O1-H···N in BTHMB-a formed by the O1-H group with the N atom or O1-H···O2 in BTHMB-b formed by the O1-H group with the O2 atom is enhanced upon photoexcitation, and the strength of the O1-H···N bond is stronger, which will drive the O1-H proton to the N atom. Potential energy curves further confirm that ESIPT occurs in the N atom because of the smaller energy barrier (0.39 kcal/mol). Results of dynamics simulations manifest that no surface hopping exists between the S0 and S1 states within 300 fs, and ESIPT time constants of BTHMB-a and BTHMB-b are 48 and 151 fs, respectively. While the reverse ESIPT is observed in BTHMB-b at 294 fs, implying that the O1-H proton is transferred to the N atom instead of the O2 atom. The consistency of the calculated absorption (390 nm) and fluorescence spectra (443 and 602 nm) of BTHMB-a with the experimental values (390, 410, and 605 nm) confirms this conclusion again. The charge distribution analysis shows that the charge on the proton acceptors increases, and the O2 atom has higher electronegativity because it has more negative charges. The minimum surface electrostatic potential on the N atom in BTHMB-b correlating with the pKb value is -47.38 kcal/mol, indicating that the N atom has strong basicity. Therefore, the basicity of the N atom dominates the ESIPT process rather than the electronegativity of the O2 atom.

Drying temperature effect on the characteristics of cationically polymerized kraft lignin

In this work, the effect of drying temperature (55–130 °C) on the properties of kraft lignin (KL) polymerized with [2-(methacryloyloxy)ethyl] trimethyl ammonium chloride, as a sustainable polymer (KLM) was investigated. KLM exhibited a 3-fold drop in charge density and a 10 % reduction in water solubility. These alterations were found to be associated with both chemical and physical changes determined by NMR and XPS analyses. At 55 °C, chain interactions were predominant due to electrostatic interactions amongst the pMETAC chains with the electronegative atoms present in KL. At 80, 105, and 130 °C drying temperatures, hydrolysis reactions predominated. The KLM polymer possessed, comparatively, a lesser resistance to thermal degradation than KL, and the KLM polymer had a more uniform thermal degradation behavior across the drying temperatures. Glass transition temperature, Tg, was shown to be comparable for KL across the various drying temperatures. KLM, however, showed an increasing trend as drying temperature increased, up to 130 °C, at which point Tg dropped due to KL degradation. Therefore, the drying temperature has a significant impact on the properties of kraft lignin and its cationic polymerized derivative, and it should be carefully selected to minimize the undesired changes in lignin properties.

Quantitative Characterization of Fluorine-Centered Noncovalent Interactions in Crystalline Benzanilides.

Six isomeric molecules, featuring a minimum of three fluorine atoms on either the benzoyl or aniline side, have been synthesized, crystallized and characterized through single crystal X-ray diffraction (SCXRD). In addition, two other compounds, containing six fluorine atoms, three on each of the benzoyl and aniline side of the benzanilide scaffold have also been characterized through SCXRD. This current study aims to augment the capacity for hydrogen bond formation, specifically involving organic fluorine, by elevating the acidity of the involved hydrogens through the incorporation of highly electronegative fluorine atoms, in the presence of strong N-H⋅⋅⋅O=C H-bonds. Lattice energy calculations and assessment of intermolecular interaction energies elucidate the contributions of electrostatics and dispersion forces in crystal packing. The topological analysis of the electron density is characterized by the presence of bond critical points (BCPs) involving C-H⋅⋅⋅F and F⋅⋅⋅F contacts, thus establishing the bonding nature of these interactions which play a crucial role in the crystal packing in addition to the presence of traditional N-H⋅⋅⋅O=C H-bonds.

What can attribution methods show us about chemical language models?

Language models trained on molecular string representations have shown strong performance in predictive and generative tasks. However, practical applications require not only making accurate predictions, but also explainability - the ability to explain the reasons and rationale behind the predictions. In this work, we explore explainability for a chemical language model by adapting a transformer-specific and a model-agnostic input attribution technique. We fine-tune a pretrained model to predict aqueous solubility, compare training and architecture variants, and evaluate visualizations of attributed relevance. The model-agnostic SHAP technique provides sensible attributions, highlighting the positive influence of individual electronegative atoms, but does not explain the model in terms of functional groups or explain how the model represents molecular strings internally to make predictions. In contrast, the adapted transformer-specific explainability technique produces sparse attributions, which cannot be directly attributed to functional groups relevant to solubility. Instead, the attributions are more characteristic of how the model maps molecular strings to its latent space, which seems to represent features relevant to molecular similarity rather than functional groups. These findings provide insight into the representations underpinning chemical language models, which we propose may be leveraged for the design of informative chemical spaces for training more accurate, advanced and explainable models.

A first-principles study on structural stability and magnetoelectric coupling of two-dimensional BaTiO3 ultrathin film with Cr and Cu substituting Ti site

A study on Jahn–Teller distortion reveals that the configuration with Ti-substitution is more stable than that in the case of Ba-replacement. However, magnetoelectric coupling is weak as no spontaneous polarization is formed in the doped unit cell. Taking the atomic radius, low price, and electronegativity into account, Cu was selected to replace Ti together with Cr. Formation energy and phonon spectrum show structural stability. The spontaneous polarization was calculated to be 0.110, 0.114, and 0.247 and 8.078, 0.288, and 0.255 μC/cm2, respectively, in the Cr- and Cu-doped unit cell, corresponding to the directions [100], [010], and [001]. With the application of electric fields, the total magnetic moment was generally enhanced, which resulted in a strong magnetoelectric coupling. In addition, the corresponding coefficient is more than 10 V/cmOe, indicating that the modified BaTiO3 may be a good candidate for single-phase multiferroics. Clearly, co-doping with nonferromagnetic and nonmagnetic elements increases the diversity of new multiferroics.

Encapsulation of Pd Single-Atom Sites in Zeolite for Highly Efficient Semihydrogenation of Alkynes.

Palladium (Pd)-based single-atom catalysts (SACs) have shown outstanding selectivity for semihydrogenation of alkynes, but most Pd single sites coordinated with highly electronegative atoms (such as N, O, and S) of supports will result in a decrease in the electron density of Pd sites, thereby weakening the adsorption of reactants and reducing catalytic performance. Constructing a rich outer-shell electron environment of Pd single-atom sites by changing the coordination structure offers a novel opportunity to enhance the catalytic efficiency with excellent alkene selectivity. Therefore, in this work, we first propose the in situ preparation of isolated Pd sites encapsulated within Al/Si-rich ZSM-5 structure using the one-pot seed-assisted growth method. Pd1@ZSM-5 features Pd-O-Al/Si bonds, which can boost the domination of d-electron near the Fermi level, thereby promoting the adsorption of substrates on Pd sites and reducing the energy barrier for the semihydrogenation of alkynes. In semihydrogenation of phenylacetylene, Pd1@ZSM-5 catalyst performs the highest turnover frequency (TOF) value of 33582 molC═C/molPd/h with 96% selectivity of styrene among the reported heterogeneous catalysts and nearly 17-fold higher than that of the commercial Lindlar catalyst (1992 molC═C/molPd/h). This remarkable catalytic performance can be retained even after 6 cycles of usage. Particularly, the zeolitic confinement structure of Pd1@ZSM-5 enables precise shape-selective catalysis for alkyne reactants with a size less than 4.3 Å.