Electronic Absorption Research Articles

Optimizing strength-ductility synergy of the solid-solution Ti50–ZrVNbCr MEAs via coordinately adjusting VEC and lattice constant

In this study, a series of Ti50–ZrVNbCr alloys were designed under with the constant atomic radius mismatch. It was suggested that valence electron concentration (VEC) and lattice constant, which evolve oppositely in the series of the Ti50–ZrVNbCr alloys, jointly influence the mechanical properties. Based on modeling, the evolution of ductility and yield strength of the designed alloys was predicted. Ductility was predicted to be superior in the VEC range from 4.22 to 4.25, with the lattice constant correspondently ranging from 3.340 Å to 3.334 Å. The optimization of strength-ductility synergy was discussed in terms of coordinately adjusting VEC and lattice constant. The experimental results were quite consistent with the prediction results, showing that the alloy with the VEC value of 4.25 and the lattice constant of 3.334 Å, which consisted of 50 at.%Ti, 28.1 at.%Zr, 9.4 at.%V, 9.4 at.%Nb, and 3.1 at.%Cr, possessed the best ductility and superior strength-ductility synergy.

Synthesis and Characterization of Solvated Lanthanide(II) Bis(triisopropylsilyl)phosphide Complexes.

Lanthanide (Ln) silylamide chemistry is well-developed, but the corresponding silylphosphide chemistry is immature; there are only ten structurally characterized examples of Ln(II) bis(trimethylsilyl)phosphide complexes to date and no reported derivatives with bulkier R-groups. Here, we report the synthesis of the first f-block bis(triisopropylsilyl)phosphide complexes, [Ln{P(SiiPr3)2}2(THF)x] (1-Ln; Ln = Sm, Eu, x = 3; Ln = Yb, x = 2), by the respective salt metathesis reactions of parent [LnI2(THF)2] with 2 equiv of [Na{P(SiiPr3)2}]n in toluene. Complexes 1-Ln were characterized by a combination of NMR, EPR, ATR-IR, electronic absorption and emission spectroscopies, elemental analysis, SQUID magnetometry, and single crystal X-ray diffraction. These data contrast with those obtained for related Ln(II) bis(trimethylsilyl)phosphide complexes due to the bulkier ligands in 1-Ln and also with Ln(II) bis(triisopropylsilyl)amide complexes due to a combination of longer Ln-P vs. Ln-N bonds and the softer nature of P- vs. N-donor ligands.

Crystallographic and Optical Spectroscopic Study of Metal–Organic 2D Polymeric Crystals of Silver(I)– and Zinc(II)–Squarates

Metal–organic framework materials, as innovative functional materials for nonlinear optical technologies, feature linear and nonlinear optical responses, such as a laser damage threshold, outstanding mechanical properties, thermal stability, and optical transparency. Their non-centrosymmetric crystal structure induces a higher-order nonlinear optical response, which guarantees technological applications. ZnII– and AgI–squarate complexes are attractive templates for these purposes due to their good crystal growth, optical transparency, high thermal stability, etc. However, the space group type of the catena-((μ2-squarato)-tetra-aqua-zinc(II)) complex ([Zn(C4O4)(H2O)4]) is debatable, (1) showing centro- and non-centrosymmetric monoclinic C2/c and Cc phases. The same is valid for the catena-((μ3-squarato)-(μ2-aqua)-silver(I)) complex (Ag2C4O4), (2) exhibiting, so far, only a C2/c phase. This study is the first to report new crystallographic data on (1) and (2) re-determined at different temperatures (293(2) and 300(2)K) and the non-centrosymmetric Cc phase of (2), having different numbers of molecules per unit cell compared with the C2/c phase. There are high-resolution crystallographic measurements of single crystals, experimental electronic absorption, and vibrational spectroscopic data, together with ultra-high-resolution mass spectrometric ones. The experimental results are supported for theoretical optical and nonlinear optical properties obtained via high-accuracy static computational methods and molecular dynamics, using density functional theory as well as chemometrics.

Dual-gate AlGaN channel HEMTs: advancements in E-mode performance with N-shaped graded composite barriers

Abstract This work evaluates the performance of dual gate AlGaN channel HEMTs on SiC substrate. The study analyzes two HEMT structures that differ only in barrier design, one design consists of fixed composite barriers (FCB-HEMT) i.e. there is fixed Aluminum composition x = 0.48 in the first Al x Ga1−x N barrier and x = 0.42 in the second Al x Ga1−xN barrier while the other design comprises N-shaped graded composite barriers (NGCB-HEMT) i.e. the Aluminum content varies gradually from 0.4 to 0.48 in the first AlGaN barrier and from 0.34 to 0.42 in the second AlGaN barrier. The paper concentrates on energy band diagrams, electron concentration profile, electric field distribution, drain and transfer characteristics, and the effects of high temperature on drain characteristics and mobility of the NGCB-HEMT. It has been reported that at zero gate bias, the FCB-HEMT has a drain current density of 0.137 A mm−1 while it decreases to 0.0058 A mm−1 in the case of NGCB-HEMT, thus presenting a novel approach towards enhancement-mode AlGaN HEMTs. Hence, grading can be optimized in the composite barriers to achieve enhancement mode operation of AlGaN channel HEMTs. Furthermore, the study reveals that the critical electric field of FCB-HEMT is 6.9975 M V cm−1, while that of NGCB-HEMT is 5.3124 M V cm−1, demonstrating their usefulness in electronic devices that operate at high voltages and harsh temperatures. Moreover, at higher temperatures, the phenomenon of optical phonon scattering leads to decreased mobilities, which in turn causes low drain currents relative to the drain voltage.

Computational prediction of Thermo-Elastic and charge carriers transport properties of Ba2MnReO6, Ba2NiReO6, and Sr2MnReO6 double Perovskite compounds

The present work involves a computational investigation of the elastic, thermal, and thermoelectric characteristics of Ba2MnReO6, Ba2NiReO6, and Sr2MnReO6 from the Double Perovskite family. The study verified the mechanical stability of the three compounds and investigated Young’s modulus, Poisson, bulk, and shear modulusin various stress orientations. We were also able to compute longitudinal, transverse, and average sound velocities (Vl, Vt, and Vm, in m/s), and the findings revealed that Sr2MnReO6 had a greater longitudinal velocity than the other two compounds. Thermodynamic characteristics revealed that Ba2MnReO6, Ba2NiReO6, and Sr2MnReO6exhibit low lattice thermal conductivity (Kl) at medium temperatures, strong heat absorption, and a moderate coefficient of thermal expansion.The analysis of the electron and hole charge carriers’ transport characteristics revealed that, when doped with an electron concentration close to 1020 cm−3, the two materials, Ba2MnReO6 and Sr2MnReO6, may have an excellent figure of merit surpassing 0.6 at temperatures over 600 K.

High-temperature transport properties of a two-dimensional weakly doped parabolic semiconductor

A version of the Mexican-hat Hamiltonian is used to study high-temperature transport properties of a two-dimensional weakly doped semiconductor with electron-hole symmetric bands. For a finite doping level and a temperature-dependent band gap, we find a closed analytical form of the temperature-dependent chemical potential. The effective concentrations of charge carriers participating in transport coefficients are analyzed in the space spanned by the total electron concentration and temperature. It is shown that these concentrations are the sum of a residual contribution and two thermally activated contributions, with a complicated dependence on temperature. The analytical expression for the Hall coefficient RHis also found. It is argued that it is a non-monotonic function of the doping level with the maximum at the doping nmax that is a linear function of temperature at high enough temperatures. The analysis of the real part of the interband conductivity shows that it is inversely proportional to incoming photon energy at low temperatures and that it is nearly constant over a wide energy range at high temperatures. This results are expected to be of significant importance in understanding transport and optical properties of weakly doped two-dimensional semiconductors with nearly symmetric parabolic bands.&#xD.

Structural Aspects, Binding Interactions, Biological Activity of Co(II)‐ and Ni(II)‐N′‐(2‐fluorobenzoyl)benzo[d]thiazole‐2‐carbohydrazide Chelatess

ABSTRACTN′‐(2‐Fluorobenzoyl)benzo[d]thiazole‐2‐carbohydrazide (OFBBTCH, HL) and its chelates with Co(II) and Ni(II) have been synthesized and characterized by elemental analysis, liquid chromatography‐mass spectrometry (LC–MS), Fourier transform infrared spectroscopy (FT‐IR), ultra‐violet visible (UV–vis), nuclear magnetic resonance (NMR) spectroscopy, thermogravimetric analysis (TGA), and powder X‐ray diffraction. The conductance measurements reveal that the chelates are non‐electrolytic, and the spectral analysis indicates octahedral geometry of the chelates. The kinetic and thermodynamic parameters were obtained by Coats–Redfern relations, which shows positive Gibbs's free energy and negative entropy for both chelates. The equilibrium studies carried out by pH‐metry revealed the dissociation constant (pKa) of OFBBTCH as 8.13 and the formation of 1:1 and 1:2 Co(II)‐L and Ni(II)‐L complexes in solution. The CT‐DNA binding studies carried out by electron absorption, fluorescence quenching, steady state emissions and viscosity studies revealed hyperchromism and groove binding for HL and chelates. The Kb values calculated from electron absorption studies are 2.4 × 106, 4 × 106, and 9 × 106 M−1, from the fluorescence quenching studies Ksv values are 0.1722, 0.278, and 0.748 M−1, and Kapp values are 5.9 × 104, 1.3 × 105, and 2.9 × 105 M−1 for HL, Co(II)‐OFBBTCH and Ni(II)‐OFBBTCH, respectively. Bovine serum albumin (BSA) and human serum albumin (HSA) binding interactions were carried out by electron absorption and fluorescence quenching studies. The light switching properties of the chelates, the hydrolytic and oxidative cleavage of CT‐DNA, and the antioxidant properties were evaluated. Anti‐microbial studies carried out by pour plate method showed high activity for Ni(II)‐OFBBTCH chelate. Cytotoxicity of the compounds was performed for HeLa and MCF cell lines by MTT assay. Molecular docking studies revealed the docking of HL and Co(II)‐HL at the minor groove, and Ni(II)‐HL was docked at the major groove with hydrogen bonding.

CURRENT OSCILLATIONS IN IMPURITY SEMICONDUCTORS WITH BOTH SIGNS OF CURRENT CARRIERS IN THE PRESENCE OF AN EXTERNAL ELECTRIC FIELD, A TEMPERATURE GRADIENT AND A WEAK MAGNETIC FIELD (μ_± H<<C)

It is theoretically shown for the first time that in an external electric and weak magnetic fields, when there is a temperature gradient, an impurity semiconductor radiates energy from itself with a certain frequency. The values of the frequency of current oscillations and the limit of change of the external electric field are found. It is shown that the resistance in the medium has only ohmic character. It is stated that in the above semiconductor, when the concentration of electrons and holes are determined from the obtained expression in theory, the injection of contacts plays a major role for the appearance of the indicated current oscillation in the circuit.

Two-frequency pulsed laser irradiation to stimulate the development of coniferous trees

The possibility of using radiation from a two-frequency pulsed copper vapor laser with wavelengths of 510.6 nm and 578.2 nm with an exposure of 30 to 120 s to stimulate the development of coniferous trees (spruce, pine, larch) with a single seed irradiation is shown. The stimulation effect manifests itself at various early stages of development, such as the awakening of seeds in the aquatic environment in the first hours of the experiment (according to electron absorption spectroscopy data), seed germination, and seedling growth under stressful cultivation conditions. Possible causes of light exposure to plant seeds are discussed.

Surface acoustic wave amplification by drifting electrons in semiconducting epitaxial graphene on silicon carbide

Abstract A theory is presented for the amplification of a surface acoustic wave (SAW) due to its interaction with conduction electrons in gate-controlled epitaxial graphene (epigraphene) on a SiC substrate. It is assumed that the SAW is launched onto the substrate in the direction of an external dc electric field applied to the graphene sample and causing the conduction electrons to drift at a speed greater than the speed of the SAW. The wavelength of the SAW is assumed to be shorter than the mean free path of the electrons, so that the quantum regime of interaction of those electrons with the SAW is realized. The Green’s function method is used to calculate the SAW gain as a function of the electron concentration in epigraphene and the external dc electric field strength. It is shown that the substrate-induced band gap in the electronic spectrum of epigraphene leads to a significant (at least an order of magnitude) increase in the SAW gain as compared to the case of gapless graphene. In addition, the opening of the band gap results in a non-monotonic dependence of the SAW gain on the electron concentration, controlled by the gate voltage applied to the graphene sample. This dependence is characterized by the presence of a distinct maximum at a certain value of electron concentration (of about 2 × 10 12 cm−2 for typical values of the other parameters involved), which distinguishes it from the monotonic concentration dependence of the SAW gain in gapless graphene.

A Multielectron and High-Potential Spirobifluorene-Based Posolyte for Aqueous Redox Flow Batteries.

The rising energy demand driven by human activity has posed pressing challenges in embracing renewable energy, necessitating advances in energy storage technologies to maximize their utilization efficiency. Recent studies in aqueous organic redox flow batteries have focused primarily on the development of organic negative electrolytes, while the progress in organic positive electrolytes remains constrained by limitations in their redox potentials and effective electron concentrations. Herein, we report a spatially twisted chlorinated spirobifluorene ammonium salts (CSFAs), created through an unexpected green chlorination-protection pathway during the initial cycling in the flow battery cell, utilizing chloride ions from counterions in aqueous solution. The chlorinated, nonplanar spiral structure of CSFAs possesses a one-step four-electron transfer electrochemical property and offers exceptional resistance to nucleophilic attacks, exhibiting an unprecedented redox potential as high as 1.05 V (vs. SHE). A full redox flow battery based on CSFA-Cl (chloride ions as the counter ions) with 1.4 M electron concentration achieved an average coulombic efficiency exceeding 99.4 % and a capacity utilization reaching 95 % of the four-electron capacity for a stable cycling over 250 cycles (~22 days). The present work exemplifies the use of side reactions to develop new redox species, which can be extended to create more structurally versatile energy storage materials.

Effect of cell structures on electrical degradation of GaAs laser power convertors after 1 MeV electron irradiation and structure-optimization for improving radiation resistance

Laser wireless power transfer (LWPT) technology holds significant promise for wireless power transmission in space, necessitating that high-efficiency GaAs laser power convertors (LPCs) have strong tolerance to high-energy particle radiation. Therefore, the degradation characteristics of GaAs LPCs with different architectures under 1 MeV electron irradiation were investigated. Experimental and simulation results demonstrate that LPCs with thicker bottom cells suffer from significantly more electrical degradation. The degradation is primarily due to a reduction in electron concentrations in the base of the bottom cells, which is considerably less pronounced as the thickness of the bottom cells decreases. Based on these analyses, thinning the thickness and optimizing the doping profile for the bottom cells are proposed to improve the radiation resistance of the LPCs. Simulations show that the electrical degradation of the optimized four-junction LPCs is notably less than that of the original four-junction LPCs under the same irradiation conditions, indicating that the proposed strategies effectively enhance the radiation resistance of the LPCs.

Multifunctional gold nanoparticles for cancer theranostics.

The diagnosis and treatment of cancer can often be challenging requiring more attractive options. Some types of cancers are more aggressive than others and symptoms for many cancers are subtle, especially in the early stages. Nanotechnology provides high sensitivity, specificity and multimodal capability for cancer detection, treatment and monitoring. In particular, metal nanoparticles (NPs) such as gold nanoparticles (AuNPs) are attractive nanosystems for researchers interested in bioimaging and therapy. The size, shape and surface of AuNPs can be modified for improving targeting and accumulation in cancer cells, for example through introduction of ligands and surface charge. The interactions of AuNPs with electromagnetic radiation (e.g., visible-near-infrared, X-rays) can be used for photothermal therapy and radiation therapy, through heat generated from light absorption and emission of Auger electrons, respectively. The subsequent expansion and high X-ray attenuation from AuNPs can be used for enhancing contrast for tumor detection (e.g., using photoacoustic, computed tomography imaging). Multi-functionality can be further extended through covalent/non-covalent functionalization, for loading additional imaging/therapeutic molecules for combination therapy and multimodal imaging. In order to cover the important aspects for designing and using AuNPs for cancer theranostics, this review focuses on the synthesis, functionalization and characterization methods that are important for AuNPs, and presents their unique properties and different applications in cancer theranostics.

Toward a realistic theoretical electronic spectra of metal aqua ions in solution: The case of Ce(H2O)n3+ using statistical methods and quantum chemistry calculations.

Accurately predicting spectra for heavy elements, often open-shell systems, is a significant challenge typically addressed using a single cluster approach with a fixed coordination number. Developing a realistic model that accounts for temperature effects, variable coordination numbers, and interprets experimental data is even more demanding due to the strong solute-solvent interactions present in solutions of heavy metal cations. This study addresses these challenges by combining multiple methodologies to accurately predict realistic spectra for highly charged metal cations in aqueous media, with a focus on the electronic absorption spectrum of Ce3+ in water. Utilizing highly correlated relativistic quantum mechanical (QM) wavefunctions and structures from molecular dynamics (MD) simulations, we show that the convolution of individual vertical transitions yields excellent agreement with experimental results without the introduction of empirical broadening. Good results are obtained for both the normalized spectrum and that of absolute intensity. The study incorporates a statistical machine learning algorithm, Gaussian Mixture Models-Nuclear Ensemble Approach (GMM-NEA), to convolute individual spectra. The microscopic distribution provided by MD simulations allows us to examine the contributions of the octa- and ennea-hydrate of Ce3+ in water to the final spectrum. In addition, the temperature dependence of the spectrum is theoretically captured by observing the changing population of these hydrate forms with temperature. We also explore an alternative method for obtaining statistically representative structures in a less demanding manner than MD simulations, derived from QM Wigner distributions. The combination of Wigner-sampling and GMM-NEA broadening shows promise for wide application in spectroscopic analysis and predictions, offering a computationally efficient alternative to traditional methods.

Giant and negative magnetoresistances in conical magnets in the nonequilibrium Boltzmann equation approach

We study magnetotransport in conical helimagnet crystals using the nonequilibriun Boltzmann equation approach. Spin dependent magnetoresistance exhibits dramatic properties for high and low electron concentrations at different temperatures. For spin up electrons we find negative magnetoresistance despite only considering a single carrier type. For spin down electrons we observe giant magnetoresistance due to depletion of spin down electrons with an applied magnetic field. For spin up carriers, the magnetoresistance is negative, due to the increase in charge carriers with a magnetic field. In addition, we investigate the spin dependent Hall effect. If a magnetic field reaches some critical value for spin down electrons, giant Hall resistance occurs, i.e. Hall current vanishes. This effect is explained by the absence of spin down carriers. For spin up carriers, the Hall constant dramatically decreases with field, due to the increase in spin up electron density. Because of the giant spin dependent magnetoresistance and Hall resistivity, conical helimagnets could be useful in spin switching devices.

First-principles study on the failure and doping strengthening mechanisms at the interface of high-alumina ferritic heat-resistant steel/oxide film

This study employs first-principles calculations based on density functional theory to explore the failure mechanisms and enhancement strategies for the interface between high-aluminum ferritic heat-resistant steel and oxide film (α-Fe/Al₂O₃ interface). Establishing an interface model at the lowest-energy densely packed plane and performing tensile tests determined that fracture behavior manifests as ductile fracture at the interface. Further analysis of the charge density and differential charge density maps for various doped models confirmed the feasibility of strengthening the α-Fe/Al₂O₃ interface structure through alloy element doping. The results demonstrate that effective dopant elements (such as V, Mn, and Mo) can induce more electrons to transfer to the interface, increase electron concentration, and alter the chemical bonding nature of the interface, thereby significantly enhancing its bonding performance. This study proposes a method to enhance the interface of high-aluminum ferritic heat-resistant steel through doping, providing a theoretical foundation for further research on similar heat-resistant steel surfaces with Al₂O₃ films.

Thermal atomic layer deposition-processed InHfZnO thin film transistors with excellent stability

In recent years, the downscaling of transistors has sparked considerable interest in the advancement of amorphous oxide semiconductors, particularly indium-hafnium-zinc oxide (IHZO) has remarkable potential in applications such as high-resolution displays and 3D NAND. For the first time, we propose the fabrication of IHZO thin film transistors (TFTs) via thermal atomic layer deposition (TH-ALD). The preparation, electrical properties, and stability of IHZO TFTs are investigated. The performance of TFT deposited at 250 °C and annealed in N2 atmosphere at 300 °C exhibits a high field-effect mobility (μ) of 22.53 cm2/Vs, a high Ion/Ioff of ∼107, a low threshold voltage (Vth) of 0.15 V, and a minimum subthreshold swing (SS) of 0.24 V/decade. Furthermore, the threshold voltage shifts (ΔVth) in TFTs annealed in N2 and O2 are 0.31 and 0.16 V, respectively. These enhancements are attributed to the defects suppression and remaining ionized oxygen vacancies result in increased electron concentration in N2-annealed films. In comparison, O2 annealing causes a reduction in field effect mobility but concurrently enhances stability due to the direct passivation of defects, which leads to fewer oxygen vacancies. Additionally, Hf content can also impact the performance of TFT devices, even a small addition of Hf also results in the effective reduction of the carrier concentration. These findings provide valuable insights into the device mechanism of IHZO TFTs, presenting a novel avenue for comprehending and augmenting their overall performance.

A bis-Phenolate Carbene-Supported bis-μ-Oxo Iron(IV/IV) Complex with a [FeIV(μ-O)2FeIV] Diamond Core Derived from Dioxygen Activation.

The diiron(II) complex, [(OCO)Fe(MeCN)]2 (1, MeCN = acetonitrile), supported by the bis-phenolate carbene pincer ligand, 1,3-bis(3,5-di-tert-butyl-2-hydroxyphenyl)benzimidazolin-2-ylidene (OCO), was synthesized and characterized by single-crystal X-ray diffraction, 1H nuclear magnetic resonance, infrared (IR) vibrational, ultraviolet/visible/near-infrared (UV/vis/NIR) electronic absorption, 57Fe Mössbauer, X-band electron paramagnetic resonance (EPR) and SQUID magnetization measurements. Complex 1 activates dioxygen to yield the diferric, μ-oxo-bridged complex [(OCO)Fe(py)(μ-O)Fe(O(C═O)O)(py)] (2) that was isolated and fully characterized. In 2, one of the iron-carbene bonds was oxidized to give a urea motif, resulting in an O(CNHC═O)O binding site, while the other Fe(OCO) unit remained unchanged. When the reaction is performed at -80 °C, an intensively colored, purple intermediate is observed (INT, λmax = 570 nm; ε = 5600 mol L-1 cm-1). INT acts as a sluggish oxidant, reacting only with easily oxidizable substrates, such as PPh3 or 2-phenylpropionic aldehyde (2-PPA). The identity of INT can be best described as a dinuclear complex containing a closed diamond core motif [(OCO)FeIV(μ-O)2FeIV(OCO)]. This proposal is based on extensive spectroscopic [UV/vis/NIR electronic absorption, 57Fe Mössbauer, X-band EPR, resonance Raman (rRaman), X-ray absorption, and nuclear resonance vibrational (NRVS)] and computational studies. The conversion of the diiron(II) complex 1 to the oxo diiron(IV) intermediate INT is reminiscent of the O2 activation process in soluble methane monooxygenases (sMMO). Most importantly, the low reactivity of INT supports the consensus that the [FeIV(μ-O)2FeIV] diamond core in sMMO is kinetically inert and needs to open up to terminal FeIV═O cores to react with the strong C-H bonds of methane.

Boosting exciton dissociation in conjugated microporous polymers via molecular isomerization for photocatalytic degradation of antibiotics

Photocatalytic degradation of antibiotics from wastewater by polymeric photocatalysts is a powerful strategy to alleviate ecological damage and environmental pollution. Conjugated microporous polymers (CMPs) are promising in photocatalysis due to their tunable electronic structure and excellent light absorption. Nonetheless, CMPs still suffer from low exciton separation efficiency. Here, we propose a molecular isomerism strategy to promote exciton dissociation in CMPs by modulating the position of the carbonyl moiety. As a result, the introduction of carbonyl moiety with different substitution positions into the backbone of CMPs could minimize the exciton binding energy (Eb) and thus promote charge separation. PyCMPs-3 with phenanthrenequinone moiety as the acceptor featured a lower Eb of 37.19 meV, which are much smaller than that of carbonyl-free PyCMPs-1 (80.49 meV) and PyCMPs-2 (59.21 meV) with anthraquinone as the acceptor. Among them, PyCMPs-3 performed the best in photocatalytic degradation of ofloxacin (99 %) at a concentration of 144 ppm, which was significantly higher than that of its analogues PyCMPs-1 (26 %) and PyCMPs-2 (57 %) within 100 min under visible light exposure. In short, this work delivered a novel molecular isomerism strategy to minimize Eb by regulating the position of the carbonyl moiety for enhancing the photocatalytic degradation efficiency, promoting the development of CMPs for practical environmental remediation applications.

Synthesis, spectroscopic characterization, DFT analysis, antibacterial, antifungal, antioxidant, molecular docking, and ADME study of 3,4-dihydro-2H-napthalen-1-one tagged chalcone derivatives

Chalcone derivatives were synthesized from 3,4-dihydro-2H-naphthalen-1-one using a base-catalyzed Claisen-Schmidt reaction and characterized by FT-IR, ¹H NMR, and ¹³C NMR spectroscopy. Density functional theory (DFT) with the B3LYP/6-311G(d,p) basis set was employed to explore the structural, electronic, and quantum properties of the compounds. Simulated electronic absorption spectra for compounds 3c and 3e in gas phase, DMSO, and DCM were generated using time-dependent DFT (TD-DFT). Compound 3c's first singlet excited state shifted from 376.10 nm in the gas phase to 390.08 nm in DMSO, while compound 3e shifted from 381.58 nm to 383.54 nm in DMSO. Experimental absorption values matched the theoretical predictions, with higher oscillator strengths in DMSO and DCM indicating solvent-enhanced transition probabilities. The antimicrobial activity of the chalcones was evaluated against four bacterial strains (E. coli, B. subtilis, S. aureus, and Streptococcus spp.) and four fungal strains (R. oryzae, P. chrysogenum, A. niger, and C. albicans). Compounds 3d and 3f showed strong antibacterial activity with MIC values of 3.9 µg/mL and moderate antifungal activity. Antioxidant properties were assessed using DPPH and hydroxyl radical assays, with compound 3d demonstrating 75.8 % and 76.4 % scavenging activity for OH and DPPH radicals, respectively. ADME studies were conducted to evaluate pharmacokinetics, and molecular docking studies revealed strong binding affinities. Compounds 3a and 3e had docking scores of -8.7 kcal/mol with the E. coli protein (PDB ID: 1KZN), while 3d and 3f performed best against B. subtilis (PDB ID: 1BAG) and S. aureus gyrase (PDB ID: 2XCT), with scores of -9.1 and -8.3 kcal/mol, respectively. Molecular dynamics simulation of compound 3d with 1BAG over 100 ns confirmed stable binding. These findings suggest chalcone derivatives have strong potential for pharmaceutical development.