Conduction Equation Research Articles

Preparation, Characterization, In Vitro Biological Evaluation, DFT Calculations, and Molecular Docking Investigations of 1H-Imidazole-2-Carboxylic acid and Histidine-Based Mixed-Ligand Complexes.

Mixed-ligand complexes incorporating 1H-Imidazole-2-Carboxylic acid (IMCA) and Histidine (LHIS) show promise for biomedical and biotechnological applications. This study synthesizes and characterizes FeIMCALHIS, CoIMCALHIS, and NiIMCALHIS coordination compounds using metal chloride salts (FeCl3.6H2O, CoCl2.6H2O, NiCl2.6H2O) in ethanolic solutions. The complexes are characterized by spectroscopic methods (IR, UV-vis, and mass spectra), elemental analysis, conductivity, magnetic, and thermal analysis. Molar conductivity indicates their non-electrolytic nature. UV-vis spectra reveal absorption bands with pathochromic shifts, and electronic spectra show characteristic metal-ligand transitions, indicating their structural configuration and coordination geometry. 3D geometry optimization shows six-coordination around Fe(III) and Co(II) in FeIMCALHIS and CoIMCALHIS, and four-coordination around Ni(II) in NiIMCALHIS. Analysis of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) suggests decreased electron donation ability upon coordination. Electronic structure parameters (HOMO, LUMO, ionization potential, energy gap, electron affinity, chemical potentials, and electronegativity) provide further insights into stability and reactivity. The metal complexes exhibit enhanced antimicrobial, antioxidant, and anti-inflammatory activity compared to individual ligands, with FeIMCALHIS showing notable antimicrobial activity. Molecular docking analysis reveals strong binding interactions with target proteins, highlighting their potential therapeutic applications.

Design and Technological Aspects of Integrating Multi-Blade Machining and Surface Hardening on a Single Machine Base

Modern mechanical engineering faces high competition in global markets, which requires manufacturers of process equipment to significantly reduce production costs while ensuring high product quality and maximum productivity. Metalworking occupies a significant part of industrial production and consumes a significant share of the world’s energy and natural resources. Improving the technology of manufacturing parts with an emphasis on more efficient use of metalworking machines is necessary to maintain the competitiveness of the domestic machine tool industry. Hybrid metalworking systems based on the principles of multi-purpose integration eliminate the disadvantages of monotechnologies and increase efficiency by reducing time losses and intermediate operations. The purpose of this work is to develop and implement a hybrid machine tool system and an appropriate combined technology for manufacturing machine parts. Theory and methods. Studies of the possible structural composition and layout of hybrid equipment at integration of mechanical and surface-thermal processes were carried out, taking into account the basic provisions of structural synthesis and componentization of metalworking systems. Theoretical studies were carried out using the basic provisions of system analysis, geometric theory of surface formation, design of metalworking machines, methods of finite elements, and mathematical and computer modeling. The mathematical modeling of thermal fields and structural-phase transformations during HEH HFC was carried out in ANSYS (version 19.1) and SYSWELD (version 2010) software packages using numerical methods of solving differential equations of unsteady heat conduction (Fourier equation), carbon diffusion (2nd Fick’s law) and elastic–plastic behavior of the material. The verification of the modeling results was carried out using in situ experiments employing the following: optical and scanning microscopy; and mechanical and X-ray methods of residual stress determination. Formtracer SV-C4500 profilograph profilometer was used in the study for simultaneous measurement of shape deviations and surface roughness. Surface topography was assessed using a Walter UHL VMM 150 V instrumental microscope. The microhardness of the hardened surface layer of the parts was evaluated on a Wolpert Group 402MVD. Results and discussion. The original methodology of structural and kinematic analysis for pre-design studies of hybrid metalworking equipment is presented. Methodological recommendations for the modernization of multi-purpose metal-cutting machine tool are developed, the implementation of which will make it possible to implement high-energy heating with high-frequency currents (HEH HFC) on a standard machine tool system and provide the formation of knowledge-intensive technological equipment with extended functionality. The innovative moment of this work is the development of hybrid metalworking equipment with numerical control and writing a unique postprocessor to it, which allows to realize all functional possibilities of this machine system and the technology of combined processing as a whole. Special tooling and tools providing all the necessary requirements for the process of surface hardening of HEH HFC were designed and manufactured. The conducted complex of works and approbation of the technology of integrated processing in real conditions in comparison with traditional methods of construction of technological process of parts manufacturing allowed to obtain the following results: increase in the productivity of processing by 1.9 times; exclusion of possibility of scrap occurrence at finishing grinding; reduction in auxiliary and preparatory-tasking time; and reduction in inter-operational parts backlogs.

Design, synthesis, characterization, DFT, molecular docking, and in vitro screening of metal chelates incorporating Schiff base

Hydrazones, with an azomethine -NHN=CH group, are extensively researched due to their easy preparation and numerous pharmaceutical benefits. A hydrazone derivative was formed by combining N,N-dimethyl amino benzaldehyde (1) and hydrazine hydrate (2), producing-4-(methanehydrazonoyl)-N,N-dimethylaniline (3). The final product (H1L) ligand was produced by reacting with ethyl acetate. The new complexes were formed by reacting Co(II), Ni(II), Cu(II), and Zn(II) with the ligand in a 1M:2L molar ratio. Complexes were synthesized with high yields. Metal chelate structures were identified through elemental analyses, FT-IR, magnetic moment, XRD, and molar conductivity tests. According to FT-IR findings, the Schiff base ligand displayed neutral bidentate properties by binding with metal ions via the azomethine N and carbonyl O. Magnetic moment research indicated an octahedral structure and high electrolytic properties, with the exception of Co(II) and Zn(II) complexes, which were observed to be non-electrolytes. Theoretical calculations were performed using DFT. The synthesized complexes were tested for antibacterial activity against two types of Gram-positive bacteria: S. aureus and B. subtilis. Molecular docking analysis revealed information about the ligand's binding energy and interaction with the S. aureus receptor. KEY WORDS: Hydrazinylidene, DFT, Antibacterial activity, Molecular docking Bull. Chem. Soc. Ethiop. 2024, 38(6), 1625-1638. DOI: https://dx.doi.org/10.4314/bcse.v38i6.10

Novel Cu(II) and Zn(II) Nanocomplexes Based on 5,6‐Diphenyl‐1,2,4‐Triazine: Preparation, Spectroscopic, TD‐DFT Calculations, Molecular Docking and Solvatochromic Studies

ABSTRACTThe reaction between 2‐hydroxy‐1‐naphthaldehyde and 3‐hydrazino‐5,6‐diphenyl‐1,2,4‐triazine produced a novel hydrazone ligand (DTHMN), which reacted with Cu(II) and Zn(II) metal ion in molar ratio 1:1, giving octahedral Cu(II)‐DTHMN and tetrahedral Zn(II)‐DTHMN nanosized complexes. The structural geometries have been elucidated on the basis of elemental analysis, nuclear magnetic resonance, infrared, electronic, and electron spin resonance spectra, and magnetic and molar conductance measurements as well as x‐ray diffraction and thermal analysis. TEM analysis showed that Zn(II)‐DTHMN complex has nano‐rode morphology shape. On the other hand, Cu(II)‐DTHMN has sphere shape within nanodomain. The DTHMN ligand exhibits ONN chelating sites through N‐triazine ring, azomethine nitrogen, and deprotonated OH group, forming the mononuclear metal complexes. The synthesized compounds showed a distinct solvatochromic behavior in different polar solvents. A bathochromic alteration is observed when moving from less to high polar solvents, indicating strong solute–solvent interactions accompanied by intramolecular charge transfer (ICT). The ground and excited state dipole moments of these compounds were determined experimentally by solvatochromic shift method using Bilot–Kawski, Lippert–Mataga, Bakhshiev, and Kawski–Chamma–Viallet functions and a microscopic Reichardt's solvent polarity parameter (ETN). The dipole moment is increased significantly upon excitation referring to stabilizing the excited species includes n–π* transition by polarity of solvent. The experimental results are generally consistent with those values obtained by B3LYP/GENECP method at 6‐311G(d,p) basis set for C, H, N, and O atoms and SDD (Stuttgart/Dresden) basis set for the metal atoms. The compounds were tested for antimicrobial efficiency against Gram‐positive bacteria, Gram‐negative bacteria, and fungus strain. Finally, molecular docking was used to study the interactions between donors (the current compounds) and receptors FabH–CoA complex (PDB code: 1HNJ).

Synthesis, structural characterization, thermal analysis and antimicrobial assay of Co (II) complexes derived from benzaldehyde N4-substituted thiosemicarbazone

Microwave assisted Co (II) complexes of N4 -Substituted thiosemicarbazone were synthesized (TSC-La-f) and characterized by UV-visible spectra, IR spectra, 1H and 13C NMR spectra, elemental analysis, TGA, magnetic measurements and molar conductance. On the basis of spectral data, magnetic moment and thermal analysis square planar geometry assigned to Co(II) complexes. The electrolytic nature of the complexes was confirmed by their moderately high molar conductance values. All the metal complexes were screened for antimicrobial assay. Among all the complexes (TSC-Le) showed more activity than other Co (II) complexes. From this study it was concluded that complexes are more potent bactericide and fungicide than their corresponding ligands. Keywords: Thiosemicarbazones, benzaldehyde, Co(II) complexes, antimicrobial activity.

Novel α-N-heterocyclic thiosemicarbazone complexes: synthesis, characterization, and antimicrobial of properties investigation.

In this paper, eight novel α-N-heterocyclic thiosemicarbazone complexes were synthesized in search of new biologically active compounds, and characterized via organic elemental analysis, nuclear magnetic resonance spectroscopy, infrared spectra, thermogravimetric analysis, ultraviolet-visible spectroscopy, molar conductance and magnetic susceptibility measurements. The in vitro antimicrobial activity of these complexes was examined against ten disease-causing pathogens: Gram-positive bacteria (Micrococcus luteus ATCC9341, Staphylococcus epidermidis ATCC12228, Bacillus cereus RSKK863) and Gram-negative bacteria (Pseudomonas aeroginosa ATCC27853, Klebsiella pneumonia ATCC27853, Enterobacter aerogenes ATCC51342, Salmonella typhi H NCTC9018394, Shigella dysenteria NCTC2966, Proteus vulgaris RSKK96026) and yeast (Candida albicans Y-1200-NIH). The results revealed that the α-N-heterocyclic thiosemicarbazone compounds showed potent activity. It was observed that all thiosemicarbazone complexes were more susceptible to Gram-negative strains based on the presence of an electron-withdrawing substituent (-Br/-Cl/-F). It was determined that thiosemicarbazone Cu2+complexes showed stronger antifungal effects.

Corrective and new research frontier of dual-phase -lag non-fourier heat conduction in functionally graded cylindrical materials with bi-directional property variations

This study presents a novel and corrective analysis of Dual-Phase-Lag (DPL) non-fourier heat conduction in functionally graded cylindrical materials with bi-directional property variations. For general purposes, the 2-D DPL model was employed and solved in a polar coordinate system for an FGM cylinder whose material properties vary exponentially in the axial and radial directions. The proposed model's analytical and numerical solutions were obtained through the SOV method and implicit FDM with a non-uniform grid. Moreover, the effect of the inhomogeneity parameter in the Fourier, Cattaneo–Vernotte (C–V), and DPL models has been analyzed. The results indicate that the DPL model achieves temperature stability in less time when contrasted with the C–V model. In addition, the reduced inhomogeneity parameters result in quicker attainment of a steady temperature and the induction of higher temperatures. The thermal wave propagation in the DPL model is consistently greater than that in the C–V model. In addition, an increase in time lag for heat flux enhances thermal wave properties (amplitude, wavelength, propagation speed etc.); conversely, an increase in time lag for temperature gradient counteracts wave properties and augments heat release. Nevertheless, the present outcomes offer a straightforward multivariate analytical and numerical solution for a finite cylinder's non-Fourier heat conduction equation under diverse boundary conditions.

Analysis of forming mechanism and influencing factors of thermoacoustic plate end temperature difference

In order to explore the formation mechanism and influencing factors of the temperature difference between two ends of the plate stack, an expression of the temperature change of the stack with time was established based on the two-dimensional heat conduction equation. Based on this, the finite element model of heat transfer between a single thermoacoustic plate stack and the gas above it is established in Ansys, and the temperature of the plate stack is solved. When the sound field is constant, the variation law of the temperature of the stack with the working time and space is obtained, and the formation mechanism of the temperature difference between the two ends of the plate stack is revealed. From the calculation results, it is found that the net heat transfer between the gas and the plate stack is mainly reflected in the two ends of the plate stack, and the contribution of the air mass in the middle part is mainly the relay heat transfer. In the process of working, part of the sound work is converted into the internal energy of the air mass, which makes the gas temperature on the surface of the plate rise as a whole. The working frequency, stack length and stack thermal conductivity are taken as the influencing factors. When no load is added, the variation of the temperature of the high and low end of the stack with the working time under different working conditions is analyzed. And the theory of series between short plates is put forward to explain the formation mechanism of large temperature difference between the two ends of the plates. In order to further reduce the cooling temperature of thermoacoustic refrigerator, a new research method and exploration direction are proposed.

On the analytical solution of the one-dimensional convection–conduction equation for packed-bed thermal energy storage systems

Temperature distribution modeling within packed-bed thermal energy storage (PBTES) systems is crucial to simulate its integration into heat sources and perform techno-economic analyses to assess the actual benefits associated with its use. This article proposes a one-dimensional convection–conduction equation to model a fluid–solid system by assuming volume-averaged properties for the energy balance and determines the analytic solution through Integral Transforms. The present study analyzes the applicability of this analytic solution considering different operational conditions of PBTES systems. The article revealed that the Péclet number (Pe) and the fluid-to-solid capacity ratio (κ) must be limited to obtain stable solutions, while the dimensionless time τ cannot be arbitrary despite computing an analytic solution. A sensitivity study of the solution for parameter a=κPe/2 defined the minimum dimensionless time required for the solution to be stable. This stability was assessed with existing experimental setups, indicating the solution’s feasibility for air–solid PBTES systems.

Synthesis of Novel Cu(II), Co(II), Fe(II), and Ni(II) Hydrazone Metal Complexes as Potent Anticancer Agents: Spectroscopic, DFT, Molecular Docking, and MD Simulation Studies.

Metal complexes [FeL], [NiL]·H2O, [CuL], and [CoL]·H2O were formed by the ligand (L, 4-fluoro-N'-(2-hydroxybenzylidene)benzohydrazide) reacting with Fe(OAc)2, Ni(OAc)2·4H2O, Cu(OAc)2·H2O, and Co(OAc)2·4H2O. The produced compounds were characterized using a variety of methods, such as NMR, UV-vis, FT-IR, magnetic susceptibility, elemental analysis, and molar conductivity. The spectrum of the data indicates that the geometry of the complex molecular structures is octahedral with six coordination sites. The ligand and its different metal complexes were tested in a human lung cancer cell line and a normal embryonic kidney cell line. A cytotoxic assay revealed that L-Cu is the most potent chelate against cancer cell lines. A computational study was performed to rationalize this finding. The binding potential of relatively active compounds to a suitable target was analyzed. For this purpose, a target that is known to be inhibited by small compounds with a scaffold similar to that of the synthesized compounds, lysine-specific demethylase 1 (LSD1), was first determined. Molecular docking studies demonstrated that L-Cu has a high binding potential to LSD1 at a level comparable to that of a standard ligand. Molecular dynamics (MD) simulations revealed that L-Cu and L form stable complexes with the enzyme. Furthermore, the MD simulation study showed that L-Cu remained inside the binding pocket of the enzyme during the 200 ns simulation period. Density functional theory (DFT) studies demonstrated that the chemical stability of L was higher than that of its chelate form, L-Cu.

Synthesis, Characterization, Biological, ADMET, and Molecular Docking Studies of Transition Metal Complexes of Aminopyridine Schiff Base Derivative

Abstract1,2‐diphenylethane‐1,2‐diylidene)bis(azanylylidene))bis(pyridine‐3‐thiol) ligand was synthesized by refluxing 2‐aminopyridine‐3‐thiol with benzil in 2 : 1 molar ratio. Manganese(II), Cobalt(II), Nickel(II) and Copper(II) were also synthesized using the same method. All the compounds were characterized employing various analytical and spectroscopic methods, including melting point determination, molar conductance, magnetic moment measurement, 1H‐NMR, FTIR, mass spectrometry, EPR, and UV‐Visible spectroscopy. The antimicrobial potential of ligand and its complexes was assessed against B. subtilis, S. typhi, A. flavus, and M. phaseolina using the well‐diffusion method. Gentamycin and Amphotericin B were used as standard reference drugs. The complexes revealed more potent antimicrobial action than the ligand. Molecular docking studies were performed using crystal structures of B. subtilis, and A. flavus receptor proteins. In silico studies suggested the druglikeness potential of the synthesized compounds. The Nickel(II) complex showed superior biological efficacy based on the experimental and computational results.

Fully coupled finite strain consolidation analysis for soft clay treated by prefabricated horizontal drain with vacuum and heat preloading

This paper established a one-dimensional fully coupled finite strain consolidation analysis for soft clay treated by thermal prefabricated horizontal drain under vacuum and heat preloading with the consideration of thermal elastic viscoplastic (TEVP) behaviors of soft clay. Firstly, the governing equations for finite strain consolidation, heat conduction, and heat convention process have been carefully derived based on the well-established Gibson’s large strain consolidation theory and TEVP constitutive model. Secondly, the accuracy and reliability of the numerical method have been verified with benchmark cases and three physical model tests. Then, improvement of consolidation efficiency rate (IER) was defined and used to study the effect of three variables on consolidation efficiency. Last but not least, a graphical user interface (GUI) was provided to support researchers and engineers in utilizing the proposed numerical method for conducting consolidation analysis of soft soil treated in the same or similar fashion.

La3+-Schiff base complex for the degradation of Rhodamine B: Kinetic studies and reactive species identification

The research investigates the characteristics of the La-H2L complex through molar conductivity experiments, XPS, SEM, EDX, BET and UV-visible spectroscopy, revealing a band gap of 2.76 eV. Its photocatalytic efficacy was tested for the degradation of Rhodamine B (RhB) dye under UV light. Optimization studies determined the optimal conditions for pH, initial dye concentration, and catalyst dosage, leading to a 72.2 % reduction in RhB concentration. Kinetic analysis demonstrated that the degradation followed pseudo-first-order kinetics with a rate constant of 0.0169 min⁻¹. Scavenger studies identified hydroxyl radicals, holes, and superoxide radicals as the primary reactive species involved. High-Resolution Mass Spectrometry (HRMS) identified intermediate products and provided insights into the degradation pathways. The La-H2L complex exhibited remarkable stability and reusability, retaining 85 % of its photocatalytic activity after five cycles. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) confirmed the structural integrity and stability of the complex post-degradation. These results underscore the La-H2L complex's potential as a highly effective and durable photocatalyst for environmental remediation.

Numerical method research and characteristics analysis on frozen start-up process of high-temperature heat pipe

Future space exploration technology requires a long-life and reliable power source that is not reliant on solar energy. Space micro-reactors are able to meet this need, with Heat Pipe Cooled Reactors (HPR) emerging as a notable type of space micro-reactor that has attracted widespread attention in recent years. The HPR utilizes high-temperature alkali metal heat pipes for heat transfer, which presents certain complexities due to the solid state of the alkali metals working medium at room temperature. This results in a three-phase transition during the high-temperature heat pipes start-up process, which significantly impacts the heat transfer characteristics and dynamic behavior of the HPR start-up process. Consequently, thorough research is necessary in this area. Numerical simulation is a crucial tool that can effectively analyze, predict, and guide experiments. This article utilizes the Finite Volume Method (FVM) to develop a simulation code for high-temperature heat pipe frozen start-up. Various physical models are integrated to describe different components of the heat pipe: the container is represented by a two-dimensional axisymmetric heat conduction equation, the wick region utilizes a Fixed Grid Method (FGM) to depict the melting process of the medium, and the vapor channel is described through a two-dimensional axisymmetric compressible laminar flow. The wick region and vapor channel are coupled through the evaporation and condensation of the medium. For the vapor channel, numerical methods such as SIMPLE and PISO are used for solving. Adaptive time step and OpenMP acceleration are employed in the code to enhance computational efficiency. Finally, by comparing the calculated results with experimental data, the feasibility and accuracy of the code are assessed, highlighting special phenomena during the start-up process. The findings confirm that the developed code accurately predicts parameter changes during start-up, and can serve as a heat pipe analysis module for multi-physics coupling analysis of HPR.

MATHEMATICAL MODELS OF THE THERMAL PROTECTION COATING OF THE GAS GENERATOR OF THE HYDROGEN STORAGE AND SUPPLY SYSTEM

The article describes the properties of the thermal protection coating of the gas generator of the hydrogen storage and supply system by two transfer functions with Hurwitz polynomials of the third order. Obtaining such transfer functions is based on the solution of the non-stationary heat conduction equation, represented in operator form using the integral Laplace transform, and in which approximating spline functions in the form of second-order polynomials are used. The article gives the solution of the non-stationary thermal conductivity equation, which describes the thermal processes in the heat-protective coating of the gas generator of the hydrogen storage and supply system under the thermal effect of a fire. This solution comes in the operator form for the surface temperature of the heat-protective coating on the side of the gas generator wall. The peculiarity of this decision is the presence of hyperbolic functions of an irrational argument in its composition. The structural and dynamic scheme of the thermodynamic system ‘gas generator wall – heat-protective coating’ is presented, the feature of which is the presence of two entrances. The signal at the scheme’s first input reflects the thermal effect of the fire, and the signal at the second input reflects the thermal state of the gas generator cavity. An equivalent mathematical transition to the description of thermal processes in the heat-protective coating of the gas generator of the hydrogen storage and supply system was carried out. This transition happened due to the use of spline functions, which approximate the hyperbolic functions of the irrational argument and are polynomials of the second order. The article gives a verbal interpretation of the algorithm for determining the transfer functions of the heat-protective coating of the gas generator of the hydrogen storage and supply system and also an example of its implementation. Furthermore, it shows that for the given conditions of functioning of the gas generator heat-protective coating, the relative errors in approximation of hyperbolic functions by second-order polynomials do not exceed 1.7 %, and the average relative error when equivalent replacement of transfer functions does not exceed 3.8 %. Keywords: gas generator, hydrogen storage and supply system, thermal protection coating.

RESEARCH OF THE DESTRUCTION CONDITIONS OF GLAZING OF ENCLOSING STRUCTURES UNDER THE CONDITIONS OF THERMAL INFLUENCE OF FIRE

The article presents the main results of mathematical modelling of the destruction of glazing of enclosing building structures with translucent elements under fire conditions. The authors analyse literature data on calculating the fire resistance of enclosing building structures with glazing. The results show that improving methods for predicting the fire resistance of glazing is relevant. Mathematical models for the numerical study of the behaviour of glazing under the thermal influence of the standard fire temperature regime are substantiated. Mathematical models of the heat transfer process involve using a non-stationary differential equation of heat conduction with boundary conditions of the third kind, accounting for the convective and radiant heat exchange between the air in the room with the fire and the glazing. As a criterion for the destruction of glazing under the influence of fire, the authors establish the temperature resistance parameter, which is determined based on the mechanical characteristics of the glass. The article highlights the relevant data on the study of temperature indicators and the mechanism of glazing failure, using mathematical modelling with well-founded mathematical models. It obtains the results of the thermal calculation by applying the finite difference method for solving the non-stationary differential equation of thermal conductivity. The methodology for determining the time of glazing failure under the influence of the standard temperature regime of a fire using the calculation parameters obtained based on well-founded mathematical models is substantiated. An analysis of the adequacy of the obtained calculation data was carried out by comparing them with the results of experimental studies using statistical criteria. As a result of the analysis, the authors confirmed the validity of the calculation data. A complete factorial experiment was conducted based on well-founded mathematical models, which revealed the regularities of the dependence of the parameters of thermomechanical processes in single-layer glass on its structural characteristics. The revealed regularities have the form of linear regression dependences of the destruction time on the thickness of the glazing and the maximum length of the glass panel without bars. Using the regularities of the dependence of the parameters of thermomechanical processes in single-layer glazing on its structural characteristics, the authors constructed reference tables for evaluating the fire resistance of enclosing structures with glazing. The research obtained new scientific data on the study of the behaviour of glazing of enclosing building structures under the thermal influence of fire through mathematical modelling, which is the basis for improving the methods of calculating the fire resistance of enclosing structures with translucent elements. Keywords: enclosing building structures, glazing, fire resistance limit, calculation method, glass heat resistance.

Heterocyclic Schiff Base Complexes of Bivalent Transition Metals: Microwave-Assisted Green Synthesis, Structure Elucidation and Antimicrobial Studies

A heterocyclic Schiff base ligand [LH] namely {5‐[(E)‐[(1H‐pyrrol‐2‐yl)methylidene]amino]‐ 1,3,4‐thiadiazole‐2‐thiol}(NNN donor) and its divalent transition metals (Co2+, Ni2+, Cu2+ and Zn2+) mononuclear complexes were synthesised efficiently in relatively very short times (from one-two hours to 6-15 minutes) with higher yields [from 59% (conventional method) to 90% (green method)] by microwave-assisted greener process is presented here. The ligand and its complexes were characterised by elemental analysis, molar conductance, and magnetic susceptibility measurements and spectroscopic (IR, electronic, and NMR) analyses. All investigated complexes were found to be six coordinated ML2 [1:2 (metal: Ligand) ratio] type which possessed mononuclear octahedral geometry. The ligand and its metal complexes were screened for antimicrobial activity by the disc diffusion method, and the results indicate that the metal complexes are better antimicrobial agents compared to the Schiff base and the metal complexes have followed antimicrobial trends: Cu(II) complex > Co(II) complex > Ni(II) complex > Zn(II) complex > Schiff base

Studies on a novel oxo-vanadium(V) complex of a tridentate ONO Schiff base ligand: Synthesis, characterization, X-ray crystal structure, Hirshfeld surface analysis, biological and catalytic activity

This study reports the successful synthesis and characterization of a novel oxovanadium(V) complex, [VO(L)(MeOH)(MeO)], prepared from 2-hydroxy-3-methoxybenzaldehyde and 2-methyl-3-aminoquinazoline. To elucidate the structure of the complex, we employed comprehensive characterization techniques such as CHN analysis, molar conductivity measurements, FT-IR, 1H NMR, UV-Vis spectroscopy, and single-crystal X-ray diffraction. The X-ray analysis confirmed an octahedral geometry around the V(V) center, coordinated with donor atoms from the deprotonated Schiff base ligand, an oxido group, a methanol molecule, and a methoxy group. Hirshfeld surface analysis was employed to evaluate intermolecular interactions.Furthermore, the complex exhibited impressively efficient catalytic activity in glucose oxidation under mild conditions (aqueous solution, room temperature, O2 oxidant), achieving a conversion rate of 98 %. Additionally, the antibacterial activity of the ligand and complex against various bacterial strains, including Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus cereus, was evaluated. The results demonstrated promising antibacterial potential of the [VO(L)(MeOH)(MeO)] complex, particularly against E. coli, P. aeruginosa, and B. cereus. These findings suggest potential applications of this new oxovanadium(V) complex in both catalysis and antibacterial treatments.

Exploring novel NH-form resorcinol-based schiff base and its metal complexes: Synthesis, characterization, cytotoxic activity, molecular docking and ADME studies

The research investigates the cytotoxic effects of the stable NH-form of a resorcinol-based Schiff base (HL) and its metal complexes (Zn(II), Cd(II), Cu(II), Ni(II)) on MCF-7 breast cancer cells. The structural characterization was conducted utilizing diverse analytical techniques, including mass spectrometry, elemental analysis, molar conductance, magnetic moment, UV–Vis, IR and ESR. The crystalline state analysis of HL through X-ray crystallography disclosed a hybrid structure comprising two canonical forms, specifically the quinoid and zwitterion, that contribute to resonance and diverse interactions, resulting in the development of a three-dimensional form. NMR, IR and ESR analyses showed that the HL was bidentate, using the oxygen of the hydroxyl and the nitrogen atom of azomethine, bonded to the metal center during complexation. The study explored the cytotoxic effects of HL and the various metal complexes on MCF-7 human breast cancer cells. All complexes display significant cytotoxicity (IC50 < 38.37 μM). The activity of the complexes was greater than that of the free ligand, with the Cu(II) complex followed by Zn(II) demonstrated superior cytotoxicity compared to Cd(II), and Ni(II) complexes. Notably, the Cu(II) and Zn(II) complex exhibited approximately 13.2 and 12.9 times greater cytotoxicity than the 5-F Uracil (5-FU) cancer drug. An MTT assay corroborated the antiproliferative activity. The molecular docking study has been performed for all compounds with the aromatase cytochrome P450 receptor protein associated with breast cancer (PDB code = 3eqm). ADME drug likeness model has been done.

Reflection, transmission, and AVO response of inhomogeneous plane waves in thermoporoelastic media with two-temperature equations of heat conduction

We develop a modified fluid-saturated thermoporoelastic model by introducing two temperature equations to account for the temperature differences between the solid skeleton and the pore filling. The modified two-temperature generalized thermoporoelastic (TTG) equation is an extension of the classical single-temperature Lord-Shulman (LS), Green-Lindsay, and generalized LS theories. It predicts four compressional waves and one shear wave based on the analysis of inhomogeneous plane waves. We study the exact reflection and transmission (R/T) coefficients at the interface separating two thermoporoelastic half-spaces and develop an amplitude-variation-with-offset (AVO) approximation. Comparison with the Biot poroelastic case of the water/oil contact shows that the TTG model reproduces the exact R/T results. The AVO response of oil, gas, and real CO2 geosequestration reservoirs illustrates the practical applicability of our model and provides the theoretical basis for the exploration of high-temperature resources.