Electronic Effects Research Articles

Carborane-based BODIPY dyes: synthesis, structural analysis, photophysics and applications

Icosahedral boron clusters-based BODIPY dyes represent a cutting-edge class of compounds that merge the unique properties of boron clusters with the exceptional fluorescence characteristics of BODIPY dyes. These kinds of molecules have garnered substantial interest due to their potential applications across various fields, mainly including optoelectronics, bioimaging, and potential use as boron carriers for Boron Neutron Capture Therapy (BNCT). Carborane clusters are known for their exceptional stability, rigid geometry, and 3D-aromaticity, while BODIPY dyes are renowned for their strong absorption, high fluorescence quantum yields, and photostability. The integration of carborane into BODIPY structures leverages the stability and versatility of carboranes while enhancing the photophysical properties of BODIPY-based fluorophores. This review explores the synthesis and structural diversity of boron clusters-based BODIPY dyes, highlighting how carborane incorporation can lead to significant changes in the electronic and optical properties of the dyes. We discuss the enhanced photophysical characteristics, such as red-shifted absorption and emission poperties, charge and electronic transfer effects, and improved cellular uptake, resulting from carborane substitution. The review also delves into the diverse applications of these compounds. In bioimaging, carborane-BODIPY dyes offer superior fluorescence properties and cellular internalization, making them ideal for cell tracking. In photodynamic therapy, (PDT) these dyes can act as potent photosensitizers capable of generating reactive oxygen species (ROS) for targeted cancer treatment making them excellent candidates for PDT. Additionally, their unique electronic properties make them suitable candidates for optoelectronic applications, including organic light-emitting diodes (OLEDs) and sensors. Overall, carborane-BODIPY dyes represent a versatile and promising class of materials with significant potential for innovation in scientific and technological applications. This review aims to provide a comprehensive overview of the current state of research on carborane-BODIPY dyes, highlighting their synthesis, properties, and broad application spectrum.

Cascade Reactions of Alkynyl Ketones and Amides to Generate Unsaturated Oxacycles and Aromatic Carbocycles.

We describe novel amine-mediated transformation of alkynyl ketones and amides to generate 2-methylene-2H-pyrans, substituted 3-hydroxy-9H-fluoren-9-ones, and amine-incorporated arenes. These cascade processes are initiated by conjugate addition of secondary amine followed by hydrolysis of the enamine/vinylogous amide intermediates. The product distribution is highly sensitive to the steric and electronic effects of the substituents on both the alkyne moieties, the tether structure connecting them, and the nature of the amine. Alkynyl amide participates in the Alder-ene reaction favorably to generate more reactive allene amide that reacts with amine to generate amine-incorporated arene products. These metal-free cascade reactions are a useful synthetic method that can be exploited for the construction of various hetero- and carbocyclic systems.

Electronic effect tuned ion-dipole interactions for low-temperature electrolyte design of LiFePO4-based lithium-ion batteries

Poor low-temperature performance is one of the major challenges hindering the widespread use of lithium-ion batteries. Modulation of Li+ solvation structure to facilitate desolvation process is an important strategy in electrolyte engineering under low temperature. Herein, different electronic effect groups including electron-withdrawing groups (CH2Cl) and electron-donating groups (CH3), are introduced in the weakly solvated solvent tetrahydrofuran (THF), respectively, to compare their effects on the ion-dipole interaction in the electrolyte and thus the regulation of Li+ solvation structure. Theoretical calculations combined with characterization demonstrates that the introduction of electron-withdrawing groups CH2Cl in the solvent can reduce the electron cloud density of oxygen in the THF solvent molecule, weaken the binding energy between Li+ and the solvent, and lead to more anions participating in solvation shell of Li+ and coordinating with Li+, thus accelerating the desolvation kinetics of Li+. This electrolyte-design strategy based on electronic effect tuned ion-dipole interactions has notably increased the cycling stability of the LiFePO4||Li half-cell at −20 °C, that is, it not only increases the capacity by about 10 mAh g−1 at the rate of 0.2 C, but also maintains the capacity retention rate at 97.4 % after 100 cycles. This study reveals an important electrolyte design strategy at the molecular level.

A very simple synthesis of defect-rich PdAg nanosponges for highly selective hydrogenation of furfural

Furfuryl alcohol (FA) is an important chemical and has extensive applications in varied fields. To realize the highly selective hydrogenation of furfural (FF) to produce FA, the key is the preparation of the catalysts with excellent performance. Herein, a very simple wet chemical method is developed for the one-step preparation of PdAg nanosponges (NSs). Specifically, with Pd(OAc)2 and AgNO3 as precursors, and ethylene glycol (EG) as both solvent and reducing agent, PdAg NSs can be grown and assembled at mild temperature of 40 °C. Throughout the reaction, no any surfactants and additional reducing agents are applied. The as-prepared PdAg NSs possess 3D self-supported alloy structures, “clean” surface, abundant pores, high specific surface area and rich defects. In the FF hydrogenation reaction at 60 °C under 1.5 MPa H2 pressure in the mixed solvent of ethanol and water (1 : 4 in volume ratio), the self-supported PdAg-1 NSs (1 : 1 in Pd/Ag molar ratio) exhibit superior catalytic performance than other PdAg NSs, pure Pd sample and commercial Pd/C (10%). With PdAg-1 NSs as catalyst in the absence of support, 100% FF can be converted and the selectivity toward FA is as high as 97.1% at 36.0 h of reaction. After 4 cycles, PdAg-1 NSs still maintain the high catalytic activity in FF hydrogenation and high selectivity toward FA, which may originate from the 3D self-supported structures, high specific surface area, “clean” surface, rich defects and electronic synergistic effect between Pd and Ag. This simple fabrication of PdAg NSs introduces new ideas for the synthesis of other nanostructured bi- and multi-metallic catalysts for highly selective FF hydrogenation to FA and other advanced applications.

Surface segregation on Ag@MNi (M = Pd, Pt, Rh, and Ru) core–shell nanocrystals for enhancing the oxygen reduction performance

Synthesis of cost-effective electrocatalysts for oxygen reduction reaction (ORR) has received wide attention due to their sluggish kinetics, which limits the development and application of fuel cell technique. In this work, we report a versatile synthetic approach to prepare a series of small-sized Ag@MNi (M = Pd, Pt, Rh, Ru) nanocrystals with core–shell structures by a simple solvothermal method. According to characterization analysis, surface segregation of Pd was proved in the outermost layer with the Pd-rich shell layer, which can regulate the adsorption energy of *OH. Electrochemical results show that the onset potential and half-wave potential of Ag@PdNi nanocrystals (Ag@PdNi NCs) are 1.005 and 0.913 V vs. RHE (reversible hydrogen electrode), respectively, with a Tafel slope of 55.31 mV dec-1 and strong ORR catalytic durability, which is similar to Ag@MNi (M = Pt, Rh, Ru) NCs and slightly higher than that of PdAg alloy nanoparticles (PdAg alloy NPs), PdNi alloy nanoparticles (PdNi alloy NPs), commercial Pd black and even commercial Pt/C, in alkaline medium. Density Functional (DFT) calculations show that the presence of Agcore effectively promotes the segregation of Pd atoms to the outer shell surface, where Ni provides better segregated substitution sites for Pd, which significantly improves the ORR activity and durability due to the electronic synergistic effect between Agcore nuclei and Pdshell can reduce the adsorption strength of OHads.

Revealing the Role of Electronic Effect to Modulate the Photophysics and Z-Scan Responses of o-Locked GFP Chromophores.

Three novel core green fluorescent protein (GFP) chromophore analogues, based on a doubly locked conformation and variable electronic effects by replacing one hydrogen with bromine, iodine, and methyl, respectively, have been synthesized to modulate the push-pull effect. These chromophores exhibited intramolecular H-bonding, as evidenced by single-crystal X-ray and 1H NMR studies. The fluorescence quantum yields (ϕf) of all of the chromophores were found to be more than an order of magnitude higher (∼0.2) than the unlocked chromophores (∼0.01). It was found that the electronic effect did affect the nonradiative rates, as the quantum yields were found to vary with respect to different analogues in the same solvents. The effect of the push-pull effect was also evident by a higher Stokes-shifted emission in the case of the methyl derivative with respect to the bromo- and iodo-analogues. Furthermore, the emission spectra of these GFP chromophores were found to show positive solvatochromism, which was supported by a quantum chemical calculation. A detailed study, correlating the observed spectral changes with various solvent functions and supported by computational results, established a facile proton transfer, followed by twisted intramolecular charge transfer (TICT) to be the major nonradiative channels of these chromophores. Besides, a completely novel usage of these chromophores was explored for the first time by studying their third-order nonlinear optical characteristics in DMSO using a single-beam Z-scan technique. All of the chromophores exhibited tunable nonlinear refraction (NLR) and nonlinear absorption (NLA) properties that depend upon different substituent groups present in the chromophores. Here, the NLR was due to the effect of self-defocusing, whereas the NLA was triggered by reverse saturable absorption, which is attributed to the two-photon absorption (TPA) process. Surprisingly, the efficiency of the TPA ability of the chromophores was found to be a function of the induced electronic effect. Hence, this work opens a new route for the utility of the ortho-locked GFP chromophores in the field of nonlinear optical applications.

Monte Carlo modeling of the origin of contaminant electrons on a 0.5T bi-planar Linac-MR.

In the last decade, hybrid linear accelerator magnetic resonance imaging (Linac-MR) devices have evolved into FDA-cleared clinical tools, facilitating magnetic resonance guided radiotherapy (MRgRT). The addition of a magnetic field to radiation therapy has previously demonstrated dosimetric and electron effects regardless of magnetic field orientation. This study uses Monte Carlo simulations to investigate the importance and efficacy of the magnetic field design in mitigating surface dose enhancement in the Aurora-RT, focusing specifically on contaminant electrons, their origin, and energy spectrum. The Aurora-RT 0.5 T Biplanar Linac-MR device was modeled using the BEAMnrc package using the updated EM macros, a magnetic field map generated from Opera 3D. Simulation generated phasespace data at the distal side of the first magnetic pole plate (89cm) and at machine isocenter (120cm) were analyzed with respect to electron energy spectra and electron creation origins, both with and without the static magnetic field. The presence of the main magnetic field was verified to affect the origin and distribution of contaminant electrons, removing them from the air column up to 60cm from the target, and focusing them along the CAX within the region below. Analysis of the remaining electron energy fluence reveals the net removal of electrons with energies>2 MeV and generation of electrons with energies<2 MeV in the presence of the static magnetic field as compared to no magnetic field. Moreover, in the presence of the magnetic field the integral energy contained in the contaminant electrons increases from 89cm to isocenter but is still 15% less overall than the integral energy contained in contaminant electrons without the magnetic field. This study provides an analysis of contaminant electrons in the Aurora-RT 0.5 T Linac-MR, emphasizing the role of magnetic field design in successfully minimizing electron contaminants.

Adjustment of Electronic (OMe and NO2) and Steric (CHPh2) Effects in Bis(imino)pyridinyliron Precatalysts for Producing High Molecular Weight Linear PE

AbstractBased on variations in steric and electronic substituents in the N‐aryl unit, a set of five 2‐[1‐(arylimino)ethyl]‐6‐[1‐(2‐benzhydryl‐4‐nitro‐6‐methoxyphenylimino)ethyl]pyridyliron dichloride complexes (where aryl=2,6‐dimethylphenyl (Fe‐Me2), 2,6‐diethylphenyl (Fe‐Et2), 2,6‐diisopropyl (Fe‐iPr2), 2,4,6‐trimethylphenyl (Fe‐Me3), 2,6‐diethyl‐4‐methylphenyl (Fe‐Et2Me)) were synthesized and investigated for ethylene polymerization. Their structures and compositions were confirmed by FTIR, elemental analysis, and X‐ray diffraction analysis (Fe‐Et2 and Fe‐iPr2), revealing a distorted square pyramidal geometry around the iron center. When activated in situ with MAO or MMAO, these iron complexes acted as highly active precatalysts, achieving activity levels up to 29.0×106 gPE molFe−1 h−1 for a 5‐min reaction at 60 °C. A notable characteristic of these precatalysts is their high thermal stability, maintaining significant activity (2.0×106 gPE molFe−1 h−1) at temperatures up to 100 °C. Importantly, the incorporation of strong electron‐withdrawing groups in the ligand structure favored the production of polyethylene with high molecular weights (up to 407.5 kg mol−1) across various reaction conditions, surpassing those of most previously reported iron complexes. Moreover, less hindered iron precatalysts showed higher activity compared to more hindered ones. However, the trend reversed when comparing the molecular weight of obtained polyethylene: more sterically hindered precatalysts yielded higher molecular weight polymers. The molecular weight distributions ranged from monomodal to bimodal with broad dispersity. DSC thermograms and 1H/13C NMR spectra of the polyethylene confirmed its highly linear microstructure, evidenced by sharp endothermic peaks and pronounced singlets for the −(CH2)n− repeating units.

Coordination tuning of FeNi-HMT Framework derived effective hybrid catalysts for water oxidation.

FeNi-based hybrid materials are promising oxygen evolution reaction (OER) catalysts for water electrolysis in hydrogen generation. In this work, the coordination tuning of FeNi-HMT frameworks was achieved by simply changing the Fe/Ni ratios using hexamethylenetetramine (HMT) as an organic ligand, and the derived hybrid FeNi catalysts with varied compositions were probed for OER. Incorporating varying amounts of Fe3+ by adjusting the Ni/Fe ratio results in different metal-organic framework (MOF) structures, and higher Fe feed leads to the formation of amorphous structures due to the coordination structure destruction from the weaker coordination capacity of Fe3+ compared to Ni2+ combining with the tertiary amine ligand. Among them, the FeNi-HMT (with the Fe/Ni molar ratio of 1/1) derived catalyst, consisting of Fe0.36Ni0.64 alloy/Ni0.4Fe2.6O4 spinel oxide heterostructures supported by graphitized carbon matrix, exhibits the highest OER performance. The unique structure facilitates significant electron transfer at the alloy/spinel interface due to the large work function difference between each phase. This strong electronic effect downshifts the d-band center of the catalyst and optimizes the binding energies to the crucial oxygenated intermediates, thereby promoting the OER kinetics. This work highlights the importance of the coordination tuning of FeNi-HMT frameworks for highly efficient catalyst development.

Sterically Hindered Derivatives of Pentacene and Octafluoropentacene.

6,13-Diethynylpentacene derivatives with sterically bulky substituents (Tr*, tris(3,5-di-tert-butylphenyl)methyl groups) appended to the ethynyl moieties at the 6- and 13-positions have been synthesized, as well as derivatives with electron-withdrawing fluorine groups on the 1,2,3,4,8,9,10,11-positions. These molecules are designed to investigate relationships between steric and electronic effects on the stability of pentacene toward endoperoxide formation via reaction with photosensitized oxygen in solution under ambient light (i. e., 'laboratory' conditions). It is evident from the study that stabilization through changes to the electronic characteristics of pentacene are more effective than the incorporation of sterically bulky groups at the acetylenic termini. Selected pentacene derivatives have been made into binary, amorphous films with the fullerene derivative PCBM to investigate the stability imparted by substituents against cycloaddition reactions. Overall, the introduction of steric protection through the incorporation of Tr* groups is not an efficient strategy for enhancing the persistence of pentacenes. Stabilization through fluorination proves successful for extending the lifetime of the pentacene derivatives by an order of magnitude in solution. Notably, the persistence of pentacene derivatives in solution can also be enhanced through the use of ethereal solvents stabilized with butylated hydroxy toluene (BHT) and/or an increased number of trialkylsilyl groups as substituents.

N-doping strategy for enhancing the adsorption performance of Ti2CT2 MXene for Sr ion

Radionuclides, such as strontium (Sr), are hazardous radioactive isotopes commonly found in nuclear waste, posing serious environmental and health risks due to their long half-lives and ability to bioaccumulate. Inspired by the electronic modification effect, this study theoretically predicts that doping can significantly enhance the adsorptive performance of MXenes for radionuclides. Specifically, we employed comprehensive first-principles simulations to investigate the impact of nitrogen (N) doping on the adsorption behavior of Ti2CT2 (T = O, F, OH) MXenes for Sr ions, focusing on surface N doping and C-site N doping as effective strategies to improve adsorption. The results confirmed that both types of N doping are beneficial for the adsorption performance of Ti2CT2, and the adsorption strengths of Ti2CT2 with surface N doping are significantly enhanced. This was analyzed and attributed to the ability of N doping to enhance the charge transfer between the Ti2CT2 surface and Sr ions, thus enhancing the adsorption properties. By elucidating the N doping mechanisms, this study is expected to provide theoretical guidance for the design of high-performance MXene materials in radionuclides remediation applications.

Unraveling the influence of oxygen vacancy with and without replacement on Cu&lt;i&gt;2&lt;/i&gt;O: A DFT Study

This study delves into the structural and electronic effects of oxygen vacancies in Cu2O using density functional theory (DFT) enhanced with Hubbard U corrections (DFT+U). A 3x2x1 supercell of Cu2O was employed. The study meticulously investigates the removal of 1, 2, and 3 oxygen atoms, analyzing the ensuing changes in both structural stability and electronic properties, with particular emphasis on the band gap.The structural analysis revealed that oxygen vacancy formation induces significant modifications in Cu-O and Cu-Cu bond lengths, with elongations observed around the vacancy sites in which the Cu-Cu bond length decreased to 2.4035 Å, compared to 3.0066 Å in the pristine structure. The structural distortion followed the Jahn-Teller effect, leading to the formation of isolated units and transformation in bond angles. The introduction of oxygen vacancies without replacement (WOR) caused significant distortions in the Cu2O lattice, which were more pronounced with increasing vacancy concentration. The Cu-O bond length increased from 1.8492 Å in the pristine structure to 1.9840 Å in the single vacancy configuration. However, in the oxygen vacancies with replacement (WR) the Cu-Cu bond length increased slightly to 3.0218 Å, with the Cu-O bond length expanding to 1.8505 Å. The band structure analysis indicated a decrease in the band gap with increasing vacancy concentration. The pristine Cu2O exhibited a band gap of 1.67 eV as calculated, which was increased to 1.97 eV with a single vacancy and 1.16 eV with two vacancies, reflecting the significant impact of oxygen vacancies on the material’s optoelectronic properties. The findings underscore the critical role of oxygen vacancies in modulating the structural and electronic properties of Cu2O, providing insights that are pivotal for optimizing its performance in applications like photocatalysis and solar cells.

Improved Energy Transfer in the Sensitization of Americium Enables Observation of Circularly Polarized Luminescence

AbstractThe first example of circularly polarized luminescence (CPL) from a molecular americium (Am) complex is reported. Coordination of Am(III) by a combination of thenoyltrifluoroacetonate and a chiral diphosphine oxide ligand yielded a complex with strong sensitized metal‐centered luminescence. The energy transfer process for sensitization appears to occur via a unique resonant pathway, which results in the removal of the overlap between ligand phosphorescence and sensitized Am luminescence that has often been observed. Owing to this feature, and despite the limited amount of material that could be used due to the radioactivity of 241Am, CPL could be measured. The collected luminescence and CPL spectra provide insight into the crystal field splitting of the 5D1→7F1 transition. These results pave the way for future studies of Am(III) luminescence to investigate electronic structure effects in this and other 5 f elements.

Dissecting the hydrogen bond network of water: Charge transfer and nuclear quantum effects

The molecular structure of water is dynamic, with intermolecular (H)-bond interactions being modified by both electronic charge transfer and nuclear quantum effects (NQEs). Electronic charge transfer and NQEs potentially change under acidic / basic conditions, but such details have not been measured. Here, we developed correlated vibrational spectroscopy, a symmetry-based method that distinctively separates interacting from non-interacting molecules in self- and cross-correlation spectra, giving access to previously inaccessible information. We found that OH − donated ~8% more negative charge to the H-bond network of water and H 3 O + accepted ~4% less negative charge from the H-bond network of water. D 2 O had ~9% more H-bonds compared to H 2 O, and acidic solutions displayed more dominant NQEs than basic ones.

Systematic Investigation on Acid-Catalyzed Truncation of N-Acylated Peptoids

Peptoids have emerged as a useful alternative to peptides. However, N-acylated peptoids have occasionally undergone truncation at the terminal peptoid unit under acidic conditions. We previously reported on the mechanistic and electronic aspects of the acid-catalyzed truncation of N-acylated peptoids. To gain further insight, we systematically investigated the conformational and electronic effects of the terminal side chains of peptoids. The n→π* interaction, based on cis/trans-amide bond conformation, is considered to be one of the determining factors. In this study, it was demonstrated that both conformational and electronic factors contribute to this unusual truncation.

Synthesis of New Silylated and N-Si-N bridged Urea Derivatives from Aminosilanes and Diisocyanates.

Urea derivatives of the general motifs R1(N(SiMe3)C(O)NR2R3)2 and [R1(NC(O)NR2R3)2SiMe2]n (R1=difunctional organic linker, i. e., core of diisocyanate used; R2,R3= H,nPr; H,Ph; Et,Et) were synthesized by insertion of four different diisocyanates (1,6-HMDI, 2,4-TDI, 1,3-TMXDI and 4,4'-MDI) into aminotrimethylsilanes Me3SiNR2R3 and diaminodimethylsilanes Me2Si(NR2R3)2. The products obtained were analyzed by NMR and IR spectroscopy. Insertion into aliphatic aminosilanes was found to be favored for primary over secondary amino groups. For insertion into 4,4'-methylenebis(phenylisocyanate) (4,4'-MDI), good results were obtained for silanes derived from secondary amines as well. Insertion into aminosilanes with aromatic N-bound substituents turned out to be kinetically inhibited. Elucidation of molecular structures of the products by crystallography and NMR spectroscopy revealed interesting differences in N-Si connectivity, caused by steric and electronic effects of the reactants and migration of -SiMe3 and -(SiMe2)- moieties.

Electronic Effects in Cobalt Phthalocyanine Catalysts Towards Noble-Metal-Free, Photocatalytic CO2-to-CO Reduction

Noble-metal-free CO2 reduction systems based on cobalt phthalocyanine (CoPc) and its derivatives have demonstrated remarkable photocatalytic performances; however, their structure-activity relationship with electronic tuning remains unexplored. Herein, we now provide a systematic study to investigate the electron effects of substituents on the CoPc family in photocatalytic CO2 reduction, where a Cu(I) heteroleptic photosensitizer is utilized. The highest performance can be achieved using cobalt tetracarboxylphthalocyanine in light-driven CO2-to-CO reduction, with a maximum turnover number of 2950 at 450 nm and an outstanding apparent quantum yield of 63.5% at 425 nm, over ten times the activity with the tetra-dimethylamino-substituted CoPc derivative. The favorable electron-withdrawing effects have been further verified by DFT calculations and cyclic voltammetry, which reduces the overpotential required for CO2 reduction and decreases the Gibbs free energy of the catalyst active intermediates, particularly the CO-desorption energetics.

A study of optical properties and electron energy loss spectra of ZnS by linear response theory

The linear response theory has been applied to study the optical properties and electron energy loss spectra of ZnS. The ground state is built using the Full-Potential Linearized Augmented Plane Wave method. Thereafter, the electronic properties such as band structure and density of states are calculated. Calculations of electron energy loss spectra and optical properties are performed on the top of these ground state electronic properties. The calculations are performed using three exchange–correlation kernels namely, adiabatic local density approximation, long range contribution, and the bootstrap. The random phase approximation is also considered. An approach proposed by us to find the material dependent parameter α is used in long range contribution kernel to capture more accurate optical properties. Three values of α viz 0.78, 1.09, and 1.22 are considered. It is observed that the α = 0.78 gives very good results. This proposed scheme is found to work very well for ZnS also. The effect of local field and electron–hole interaction on the spectra is examined. For example after incorporating local field effect the high frequency dielectric constant ε∞ [i.e. ε1E→0eV ], reduces by 9.19, 12.26, 13.51 and 11.02% for random phase approximation, adiabatic local density approximation, long range contribution and bootstrap kernel respectively. In EELS plasmon peak positions are found using the three kernels and random phase approximation. A good accord with experimental results is noted after incorporating local field effects. It is observed that local field effect causes redshift of prominent peak (i.e. plasmon peak) in electron energy loss spectra by 0.61 eV.

Electronic effect in bromide-modified noble metal catalysts promotes highly stable and selective hydrogenation

Halides with strong affiliation to metals are traditionally viewed as positions in heterogeneous catalysis. This study introduces a method to enhance the selective hydrogenation performance of noble metal nanoparticle catalysts (Pd, Pt, and Rh hosted on N-doped carbon, SiO2, and Al2O3) by gas-phase bromination with 1-bromooctane. Brominated Pd catalysts, particularly those supported on N-doped carbon, show significant improvements in total butene selectivity and stability in butadiene hydrogenation reactions, displaying >97.5 % selectivity to total butenes at complete conversion with 50 h stable performance even at excessive H2 (H2:butadiene = 50) and a high temperature of 473 K. Comprehensive characterizations coupled with density functional theory calculations reveal that bromide species enhance selective hydrogenation by preferentially adsorbing at stepped Pd sites, altering reaction kinetics and preventing over-hydrogenation. Bromination influences reactant and intermediate adsorption, leading to increased competitive adsorption compared to pristine catalysts. Chemisorption studies on butadiene and 1-butene support altered kinetic behaviors post-bromination. X-ray photoelectron spectroscopy analysis demonstrate an increase in surface Pdδ+ species, owing to the electron-pulling character of nearby adsorbed bromide. In situ diffuse reflection infrared Fourier transform spectroscopy with CO probe molecules confirms Br species adsorption at unsaturated Pd sites. Overall, the study provides an effective approach to tuning the electronic properties of metal catalysts and highlights the positive impact of bromination on improving the hydrogenation performance.

Synthesis of novel indazole derivatives as inhibitors of diabetics II along with molecular docking and simulation study

In the light of the pharmacological significance of the indazole and 1, 3, 4-thiadiazole scaffold, hybrid analogs of indazole and 1, 3, 4-thiadiazole (1–14) were synthesized, identified using HREI-MS, 1H, and 13CNMR, and their capability for inhibition of α-amylase and α-glucosidase enzymes was evaluated. Generally, most of the synthesized derivatives of the series exhibited good inhibition activity in comparison to the reference drug acarbose with IC50 value of 10.30 ± 0.20 for α-amylase, and 9.80 ± 0.20 for α-glucosidase. Amongst the synthesized derivatives, fluoro substituted analog 10 appeared to be the most potent inhibitor having IC50 value of 9.90 ± 0.30 for α-amylase and 9.20 ± 0.30 for α-glucosidase. A structure activity relationship (SAR) for the series was established based on electronic effects and the positions of various groups on the phenyl ring. To comprehend the chemicals' binding interactions, molecular docking along with simulation study were also carried out. Compound 10 was ranked top in the series based on docking score and interactions with receptors. Compound 10 establish more H-bond contacts with the active site's residue of alpha-amylase and α-glucosidase as compared to all other compounds. Furthermore, 10 was found to be highly stable throughout 50 ns MD simulation. As compared to the control drug, 10 revealed high stability with both α-amylase and α-glucosidase enzymes during molecular dynamics simulation.