UV-vis Absorption Spectroscopy Research Articles

Cyclodextrin-Assisted Surface-Enhanced Photochromic Phenomena of Tungsten(VI) Oxide Nanoparticles for Label-Free Colorimetric Detection of Phenylalanine.

Herein are presented the results of experiments designed to evaluate the effectiveness of host-guest interactions in improving the sensitivity of colorimetric detection based on surface-enhanced photochromic phenomena of tungsten(VI) oxide (WO3) nanocolloid particles. The UV-induced photochromic coloration of WO3 nanocolloid particles in the presence of aromatic α-amino acid (AA), l-phenylalanine (Phe) or l-2-phenylglycine (Phg), and heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin (TMβCDx) in an aqueous system was investigated using UV-vis absorption spectrometry. The characteristics of the adsorption modes and configurations of AAs on the WO3 surface have also been identified by using a combination of adsorption isotherm analysis and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). A distinct linear relationship was observed between the concentration of AAs adsorbed on the WO3 nanocolloid particles and the initial photochromic coloration rate in the corresponding UV-irradiated colloidal WO3 in aqueous media, indicating that a simple and sensitive quantification of AAs can be achieved from UV-induced WO3 photochromic coloration without any complicated preprocessing. The proposed colorimetric assay in the Phe/TMβCDx/WO3 ternary aqueous system had a linear range of 1 × 10-8 to 1 × 10-4 mol dm-3 for Phe detection, with a limit of detection of 8.3 × 10-9 mol dm-3. The combined results from UV-vis absorption, ATR-FTIR, and adsorption isotherm experiments conclusively indicated that the TMβCDx-complexed Phe molecules in the Phe/TMβCDx/WO3 ternary aqueous system are preferentially and strongly inner-sphere adsorbed on the WO3 surface, resulting in a more significant surface-enhanced photochromic phenomenon. The findings in this study provided intriguing insights into the design and development of the "label-free" colorimetric assay system based on the surface-enhanced photochromic phenomenon of the WO3 nanocolloid probe.

Spectroscopic evaluation of sesame and mustard oils treated with Murchana method

In recent years, there has been a growing interest in traditional medicinal practices such as Ayurveda, which emphasizes the use of natural ingredients for various therapeutic purposes. Vegetable oils are an integral part of our diet and have several applications in the cosmetics and healthcare industries. These oils have also been prescribed in ancient Ayurveda texts to treat various health problems. Ayurveda prescribes a processing technique called ‘Murchana’ to improve the therapeutic nature of the oils. Spectroscopic techniques have been used for quality assessment in many fields. High sensitivity and a low detection rate make spectroscopy a formidable analytical technique. This study focusses on the spectroscopic analysis of sesame and mustard oils prepared using the ayurvedic processing method ‘Murchana’. Spectroscopic analysis techniques including UV-Vis absorbance spectroscopy, fluorescence spectroscopy, and FTIR spectroscopy were employed to study the oils. Origin software was used to plot graphs of the spectra. The results indicated that the murchana process may reduce the components of the oil responsible for its oxidation, thereby increasing the shelf life of the oils. However, further investigations, including other spectroscopy and chromatography techniques, will prove beneficial in ascertaining the effects of the murchana process on vegetable oils. The study’s findings also suggest that spectroscopic techniques can be used to supplement chemical techniques to investigate the characteristics of vegetable oils.

Green Approach for Synthesis of Silver Nanoparticles with Antimicrobial and Antioxidant Properties from Grapevine Waste Extracts.

The present work aims to study the possibilities of developing silver nanoparticles using natural extracts of grape pomace wastes originating from the native variety of Fetească Neagră 6 Șt. This study focused on investigating the influence of grape pomace extract obtained by two different extraction methods (classical temperature extraction and microwave-assisted extraction) in the phytosynthesis process of metal nanoparticles. The total phenolic content of the extracts was assessed using the spectrophotometric method with the Folin-Ciocâlteu reagent, while the identification and quantification of specific components were conducted through high-performance liquid chromatography with a diode array detector (HPLC-DAD). The obtained nanoparticles were characterized by UV-Vis absorption spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM), along with assessing their antioxidant and antimicrobial properties against Gram-positive bacteria. The data collected from the experiments indicated that the nanoparticles were formed in a relatively short period of time (96 h) and, for the experimental variant involving the use of a 1:1 ratio (v/v, grape pomace extract: silver nitrate) for the nanoparticle phytosynthesis, the smallest crystallite sizes (from X-ray diffraction-4.58 nm and 5.14 nm) as well as spherical or semispherical nanoparticles with the lowest average diameters were obtained (19.99-23 nm, from TEM analysis). The phytosynthesis process was shown to enhance the antioxidant properties (determined using the DPPH assay) and the antimicrobial potential (tested against Gram-positive strains) of the nanoparticles, as evidenced by comparing their properties with those of the parent extracts; at the same time, the nanoparticles exhibited a selectivity in action, being active against the Staphylococcus aureus strain while presenting no antimicrobial potential against the Enterococcus faecalis strain.

Synthesis of substituted terpyridine nickel nitrate complexes and their inhibitory selectivity against cancer cell lines

Six terpyridine‑nickel complexes 1–6 were formed by the coordination of 4′-(4-R-phenyl)-2,2′:6′,2″-terpyridine (R = hydroxyl (L1), methoxyl (L2), methylsulfonyl (L3), fluoro (L4), bromo (L5), iodo (L6)) derivatives to nickel nitrate. The compositions and structures of these complexes were analyzed by Fourier Transform infrared spectroscopy (FT-IR), elemental analyses, electrospray ionization mass spectra (ESI-MS), solid-state ultraviolet-visible (UV–Vis) spectroscopy, and single crystal X-ray diffraction (1, 2 and 4) studies. In vitro anticancer cell proliferation experiments against SiHa (human cervical squamous cancer cell line) cells, Bel-7402 (human hepatoma cancer cell line), Eca-109 (human esophageal cancer cell line) and HL-7702 (human normal hepatocyte cell line) indicate that they have more excellent anti-proliferation effects than the cis-platin against Siha cells, Bel-7402 cells and Eca-109 cells. Especially, complex 5 showed a rather outstanding inhibitory effect against the SiHa cell line and was less toxic than the other compounds to the HL-7702 cell line, implying an obvious specific inhibitory effect. Therefore, complex 5 has the potential value to be developed as an anticancer cell-specific drug against human cervical squamous carcinoma. Molecular docking simulation, UV–vis absorption spectroscopy and circular dichroism experiments show that they prefer to bind to DNA part in an embedded binding manner.

Excimer Fluorescence of Acriflavine Dye in Glycerol and Ethylene Glycol.

This research investigates the excimerisation of acriflavine dye in ethylene glycol and glycerol solvents. Acriflavine, a member of the acridine dye family, exhibits unique fluorescence properties with applications in various fields, including cellular nucleus observation, nucleic acid analysis, and dye laser active media etc. The study explores the impact of solvent and concentration on acriflavine's emission properties, with a focus on excimer formation, which can influence its suitability as a dye laser active medium. UV-Visible absorption spectroscopy reveals concentration-dependent absorption profiles, with distinctive monomer bands. Steady-state fluorescence studies demonstrate the emergence of red-shifted excimer fluorescence bands as concentrations increase in both solvents. Temperature-dependent fluorescence studies reveal the dynamics of excimer formation, suggesting dynamic diffusion as the excimerisation mechanism. Time-resolved fluorescence spectroscopy confirms the singlet character of both monomer and excimer states, providing insights into the excimerisation process. Critical concentration values are determined, representing the equilibrium between monomeric and excimeric forms. The study also explores pH-induced spectral shifts, highlighting the influence of acidity on fluorescence properties. Overall, this research deepens our understanding of acriflavine's excimerisation in ethylene glycol and glycerol, offering insights that can enhance its diverse applications, especially in laser technologies.

Reversible Photoinduced Ligand Substitution in a Luminescent Chromium(0) Complex.

Light-triggered dissociation of ligands forms the basis for many compounds of interest for photoactivated chemotherapy (PACT), in which medicinally active substances are released or "uncaged" from metal complexes upon illumination. Photoinduced ligand dissociation is usually irreversible, and many recent studies performed in the context of PACT focused on ruthenium(II) polypyridines and related heavy metal complexes. Herein, we report a first-row transition metal complex, in which photoinduced dissociation and spontaneous recoordination of a ligand unit occurs. Two scorpionate-type tridentate chelates provide an overall six-coordinate arylisocyanide environment for chromium(0). Photoexcitation causes decoordination of one of these six ligating units and coordination of a solvent molecule, at least in tetrahydrofuran and 1,4-dioxane solvents, but far less in toluene, and below detection limit in cyclohexane. Transient UV-vis absorption spectroscopy and quantum chemical simulations point to photoinduced ligand dissociation directly from an excited metal-to-ligand charge-transfer state. Owing to the tridentate chelate design and the substitution lability of the first-row transition metal, recoordination of the photodissociated arylisocyanide ligand unit can occur spontaneously on a millisecond time scale. This work provides insight into possible self-healing mechanisms counteracting unwanted photodegradation processes and seems furthermore relevant in the contexts of photoswitching and (photo)chemical information storage.

Surfactant Composition Dependent Evolution of Electronic/Structural Properties of P3HT Nanoparticle Colloids Synthesized via Mini-Emulsion Technique

: This study investigates the influence of surfactant (sodium dodecyl sulfate, SDS) concentration on the size and optoelectronic properties of poly(3-hexylthiophene) (P3HT) nanoparticles (NPs) synthesized via the mini-emulsion technique. P3HT NPs were fabricated with varying SDS concentrations. The size dependent optoelectronic properties, including the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) levels, were analyzed through photoelectron spectroscopy in air, UV-Vis absorption spectroscopy and cyclic voltammetry. A clear trend of decreasing NP size with increasing SDS concentration was observed. Higher SDS levels resulted in smaller NPs with enhanced pi-pi stacking and shorter conjugation lengths. This structural change led to a noticeable shift in HOMO and LUMO levels, indicating a direct correlation between surfactant concentration and the electronic properties of the P3HT NPs. The absorption spectra revealed a decrease in the A0-0/A0-1 ratio with smaller NP size, suggesting a transition towards more pronounced H-aggregate characteristics. As the size of the P3HT NPs decreases, there is a notable increase in H-aggregate formation. This increase can be attributed to enhanced interchain interactions between the polymer chains. In smaller NPs, the surface area-to-volume ratio is higher, leading to more significant interactions between adjacent polymer chains. These interactions promote the formation of H-aggregates, characterized by their interchain pi-pi stacking, which differs from the intrachain coupling observed in J-aggregates.

Strategies for Effective Degradation of Methyl Orange Dye in Aqueous Solution via Electrochemical Treatment with Copper/Graphite Electrodes

This study investigated the electrochemical degradation of methyl orange dye (MO) in aqueous solution using copper/graphite electrodes as anode and cathode respectively. The process parameters such as electrolyte concentrations, current density, pH and temperature were analyzed. The results proved that copper/graphite electrodes were effective for MO degradation and the reaction followed the first-order kinetic model. The degradation efficiency decreased with increasing MO concentration and increased steadily with current density. The pH trend with degradation efficiency was pH 9 (98%) > pH 7 (96%) > pH 3 (77%) after 70 min of electrolysis time, which shows that the alkaline conditions favoured the degradation process. Fourier transform infrared spectroscopy (FTIR) and UV–Vis absorption spectroscopy confirmed the dye degradation process, with the formation of degradation intermediates. The FTIR results revealed that the oxidative degradation of MO may be initiated at the N=N azo bond, which was confirmed by quantum chemical modelling of the electronic structure parameters of MO.

Composite membranes from bio-inspired catechol-amine coatings for pervaporation desalination

Compared with reverse osmosis, pervaporation is less influenced by the osmosis pressure of the feed solution, which endows it as an attractive desalination technology. Many researches focus on developing high-performance pervaporation desalination membranes. Bio-inspired polyphenol coatings are versatile tools for engineering membrane surfaces. Here, catechol-amine chemistry was the first time applied to construct dense composite pervaporation desalination membranes via a stepwise coating method. Tannic acid (TA) and polyethyleneimine (PEI) were chosen as typical materials. Fabrication parameters, including TA and PEI concentrations in the coating solution, pH, and thermal annealing, are crucial to the desalination performance of the resulting membranes. The TA-PEI interactions were studied by the UV–Vis absorption spectroscopy method. The membrane prepared at optimal conditions exhibits excellent desalination performance. The water flux was 43 kg/(m2·h) at 50 °C for the feed of 3.5 wt% NaCl solution (95 kg/(m2·h) at 70 °C). The intrinsic hydrophilicity of the selective layer material ensures the membrane processes of good antifouling performance. This work demonstrates the possibility and potential of applying bio-inspired catechol-amine chemistry to prepare pervaporation desalination membranes.

Teaching Experimental Instrumental Analytical Chemistry Are we forming professionals, training operators or illuding students (and ourselves)?

Teaching Experimental Instrumental Analytical Chemistry Are we forming professionals, training operators or illuding students (and ourselves)?

Development of chitosan by using a zeolite‐supported CaO derived from waste chicken eggshell to remove Acid Red 1 dye from the aqueous solution

AbstractZSM‐5 zeolite modified with acetic acid eggshell and chitosan was impregnated in three distinct proportions. As nanocomposites (NCs), the purpose of the composites was to adsorb Acid Red 1 dye (AR‐1) from an aqueous solution. The characterization of chitosan@CaO/zeolite NCs included (CHT)1@(CaO/ZT)1, (CHT)1.5@(CaO/ZT)1, and (CHT)1@(CaO/ZT)1.5, as determined by FTIR, XRD, EDX, BET, TGA, and UV–Visible absorption spectroscopy. In a bulk system, the adsorption of the AR‐1 dye onto (CHT)1@(CaO/ZT)1.5 was analyzed in terms of solution temperature, pH, contact time, and NCs dosage. The most favorable parameters for achieving efficient dye adsorption were: a pH of 2, an adsorbent dosage of 0.05 g/25 mL of dye solution, and 20 mg/L of dye concentration at 22°C temperature. The reaction reached equilibrium after 120 min. The estimated adsorption efficiency of the AR‐1 dye by the prepared NCs is 99.70%. The mechanism by which the dye was sequestered onto (CHT)1@(CaO/ZT)1.5 was exothermic. The correlation coefficient (R2) for the pseudo‐second‐order adsorption kinetic model held true at different temperatures with a value of 0.99, indicating that the model accurately described the chemical interaction between the adsorbent and Acid Red (AR‐1). Adsorption processes are characterized as exothermic, feasible, and spontaneous when the Gibbs free energy (ΔG°) and enthalpy (ΔH°) changes have negative values, respectively. It was determined that the Langmuir model best described the isotherm behavior of AR‐1 dye adsorption onto (CHT)1@ (CaO/ZT)1.5. Under ideal conditions, the surface was found to be homogeneous and had a maximum adsorption capacity (qm) of 84.03 mg/g.

Simultaneous synthesis of carbon quantum dots and porous carbon using one step hydrothermal method for supercapacitor applications

The present work reports a one-step hydrothermal carbonization process used to simultaneously produce carbon quantum dots and porous carbon. The synthesized materials were characterized by using a Fourier transform infrared spectrometer (FT-IR) to study the chemical interactions, the optical properties were studied with the help of UV-visible absorption spectroscopy, and the morphology analysis of CQDs and porous carbon was examined using FESEM, in which spherical morphology confirms the formation of CQDs, while XRD confirms the amorphous nature of the porous carbon. The application of CQDs and porous materials is evaluated as a supercapacitor material by using the cyclic voltammetry technique. The specific capacitance of porous carbon was 161.33 Fg−1 at 0.01mVs−1 scan rate. This makes CQDs and porous carbon a promising candidate for applications in energy storage devices such as supercapacitors.

Insights into the binding of buspirone to human serum albumin using multi-spectroscopic and molecular docking techniques

Buspirone is an anxiolytic drug that plays a significant role in managing anxiety disorders and alleviating their symptoms as well. Several techniques were utilized to study the interaction between buspirone and human serum albumin under physiological conditions, including UV–vis absorption spectroscopy, fluorescence emission spectroscopy, circular dichroism, Fourier transform infrared spectroscopy (FT-IR), equilibrium dialysis, and molecular docking. The results of this study demonstrated that buspirone quenched the intrinsic fluorescence of human serum albumin through a mixed mechanism. Moreover, the binding constants (Kb), the quenching constants (Ksv), and thermodynamic parameters were calculated at various temperatures. The binding process of buspirone to human serum albumin showed a cooperative binding pattern, confirmed by the Scatchard diagram and Hill coefficient. Molecular docking results showed that buspirone interacted with the IIA, IIIA, and IIB subdomains of human serum albumin and slightly changed its conformation. It was also found that hydrophobic forces played a major role in this interaction. This study consequently proves that BSH as a drug can be transported by blood albumin. Additionally, due to its ratiometric response in absorbance upon binding to a biological target, HSA can be used as a molecular probe to follow biomolecular interactions.

High‐Performance of Self‐Powered UV–Visible CdS (PVP)/PbI2 Heterojunction Photodetector

Herein, the Polyvinyl pyrrolidone (PVP)‐assisted CdS/PbI2 heterojunction UV–visible photodetector is constructed by the sol–gel spin coating method. The X‐ray diffraction, scanning electron microscopy, and energy dispersive spectrometer demonstrate the synthesis and successful complexation of PVP, CdS, and PbI2. The UV–visible absorption spectroscopy and UV photoelectron spectroscopy measurements of CdS and PbI2 are carried out to prove that the CdS and PbI2 form a type II heterojunction. Compared with pure CdS film photodetector, the CdS (PVP)/PbI2 heterojunction photodetector has self‐powered characteristics, and exhibits excellent photoconductivity in the UV–visible with higher switching ratios, detection rates, and faster response times of 1.1 × 105, 9.77 × 1011 Jones, and 20 ms, respectively, which has great potential in the field of UV–visible self‐powered photodetector.

Fabrication of flexible paper-based conducting molecularly imprinted polymer as analytical devices: Electrochemically assisted solid phase microextraction and selective flexible sensor for determination of naproxen

An electrochemical method is presented for the preparation of paper-based conductive molecular imprinted polymer (CMIP) film as a recognition element of a sensor and a selective absorber in separation methods. The paper became conductive by chemically incorporating polypyrrole (PPy) doped with anion dopant. The effects of the anion dopant and oxidant type on the conductivity of the modified paper were studied. Afterward, a CMIP film based on PPy and an anionic drug as a template was electrochemically synthesized on conductive paper surface, which was then utilized as a selective sorbent for electrochemically assisted solid phase microextraction (EC-SPME) and a recognition element in fabricating flexible drug-selective sensor. Factors affecting the performance of the paper-based EC-SPME device were studied in naproxen (NAP) analysis. All quantitative analytical parameters in the EC-SPME device were obtained by UV–vis absorption spectroscopy. Under the optimal conditions, linearity was achieved within the range of 2.0 × 10−7–2.0 × 10−5 mol/L with determination coefficient (R2 = 0.99) and the limit of detection (LOD) was 0.6 × 10−7mol/L. Moreover, a fabricated paper-based NAP-selective sensor, showed Nernstian response slopes of −61.6 ± 0.5 mV decade−1 over the linear range of 4.0 × 10−7–1.0 × 10−2 mol/L and LOD was 2.0 × 10−7 mol/L. The applicability and efficiency of the paper-based analytical devices were investigated for NAP determination as a model drug in human serum samples. The recoveries were obtained in the range of 90.0–103.0 %. Accordingly, paper-based CMIPs were found to be a novel fabrication method for efficient, selective, flexible and cost-effective material for analytical devices.

Synthesis of inorganic/organic hybrid-shell antibacterial polyurea microcapsules loaded with Ag/TiO2 nanoparticles

Silver/titanium dioxide (Ag/TiO2) nanoparticles, renowned as effective inorganic antibacterial agents with a wide spectrum of activity and minimal resistance induction, encounter challenges when incorporated into organic substrates. This integration often leads to particle aggregation, resulting in a substantial reduction in antibacterial efficacy. This study devised a novel approach involving loading Ag/TiO2 nanoparticles onto polyurea microcapsules (PUMC), forming hybrid-shelled microcapsules (Ag/TiO2-PUMC) using silane coupling agents. The preparation of polyurea microcapsules offers the advantages of rapid synthesis and mild reaction conditions, facilitating industrial-scale production. Additionally, loading Ag/TiO2 nanoparticles onto polyurea microcapsules helps alleviate the aggregation issue, and the organic nature of polyurea microcapsules enhances compatibility with organic substrates. Characterization techniques, including SEM, TEM, FTIR, XRD, UV–visible absorption spectroscopy, EPR and thermogravimetric analysis, were employed to confirm the successful grafting of Ag/TiO2 nanoparticles onto the PUMC. A comparative analysis between the two silane coupling agents, KH550 and KH792, revealed that the dual amino-functional silane coupling agent, KH792, played a pivotal role in chain extension during the microcapsule self-polymerization process. The antibacterial activity of the Ag/TiO2-PUMC was evaluated against Escherichia coli and Staphylococcus aureus. Remarkably, the hybrid-shelled microcapsules exhibited outstanding antibacterial efficacy, achieving a 99.99% antibacterial rate within just 0.5 hours. This performance surpassed unmodified Ag/TiO2 nanoparticles, highlighting the enhanced antibacterial efficacy of the hybrid-shelled microcapsule structure. This study presents a successful synthesis strategy for inorganic/organic hybrid-shelled antibacterial microcapsules and provides valuable insights for refining inorganic antibacterial agents. The demonstrated approach holds substantial promise for advancing the field of organic antibacterial materials.

Novel fluorescent probes based on sulfur and nitrogen co-doped carbon dots for determination of three N-substituted phenothiazine derivatives in dosage forms

In the current work, sulfur and nitrogen co-doped carbon dots (S,N-CDs) as simple, sensitive, and selective turn-off fluorescent nanosensors were utilized for analysis of three phenothiazine derivatives, including acetophenazine (APZ), chlorpromazine (CPH), and promethazine (PZH). S,N-CDs were synthesized through a green one-pot microwave-assisted technique using widely available precursors (thiourea and ascorbic acid). HRTEM, EDX, FTIR spectroscopy, UV–Vis absorption spectroscopy, and fluorescence spectroscopy were used to characterize the as-synthesized CDs. When excited at 330 nm, the carbon dots produced a maximum emission peak at 410 nm. The cited drugs statically quenched the S,N-CDs fluorescence as revealed by the Stern-Volmer equation. The current method represents the first spectrofluorimetric approach for the determination of the studied drugs without the need for chemical derivatization or harsh reaction conditions. The importance of the proposed work is magnified as the cited drugs do not have any fluorescent properties. The fluorescence of the developed sensor exhibited a linear response to APZ, CPH, and PZH in the concentration ranges of 5.0–100.0, 10.0–100.0, and 10.0–200.0 μM with detection limits of 1.53, 1.66, and 2.47 μM, respectively. The developed fluorescent probes have the advantages of rapidity and selectivity for APZ, CPH, and PZH analysis in tablets with acceptable % recoveries of (98.06–101.66 %). Evaluation of the method's greenness was performed using the Complementary Green Analytical Procedure Index (ComplexGAPI) and Analytical GREEnness metric (AGREE) metrics, indicating that the method is environmentally friendly. Validation of the proposed method was performed according to ICHQ2 (R1) guidelines.

Rhodamine B Hazardous Dye Removal via Adsorption Using Hg(II) Coordination Polymer

Herein, we have reported the Hg(II) coordination polymer ,(Hg-CP), formulated {[Hg(L)](Cl2)](CH3CN)2}n, behaved as adsorbent against Rhodamine B dye stuff. UV-Vis absorption spectroscopy was used to conduct dye adsorption investigations on coordination polymers. Adsorption experiments were carried out in acidic (pH=3) and neutral (pH=6) media and the results showed that the compound removed the cationic Rhodamine B from water. In acidic media, the adsorption capacity of the Hg-CP was more than neutral media. Also, Hg-CP could selectively adsorb Rhodamine B dye from the Rhodamine B/Methyl orange dye mixture. The colour of the Hg-CP was white before adsorption, whereas it changed after adsorption as Rhodamine B adhered to the surface of Hg-CP.

Structural, spectroscopic, DFT studies, Hirshfeld surface analysis and antibacterial activity of Z-3-(4-bromophenyl)-3-chloroacrylaldehyde

The present paper describes the single-crystal X-ray structure of Z-3-(4-bromophenyl)-3-chloroacrylaldehyde (BCA). Hirshfeld Surface analysis was performed, providing insight into intermolecular interactions for the first time. The compound crystalizes in the monoclinic system with a space group P21/c and unit cell dimensions of a =3.9327(4) Å, b=18.5517(19), c=12.2749(14) and V=894.77(16)Å3. Z-3-(4-bromophenyl)-3-chloroacrylaldehyde was characterized using 13C and 1H NMR spectroscopy, and its thermal stability assessed with a thermogravimetric analyzer. Optical properties were investigated through UV-Visible absorption and emission spectroscopy. Density Functional Theory (DFT) calculations were performed using B3LYP theory with a basis set of SDD. HOMO-LUMO calculations, conceptual DFT and its global reactivity descriptors like hardness, electronegativity and electrophilicity of molecule were studied using G16W software. The energy gap of 4.17eV obtained from HOMO-LUMO molecular orbital energy shows that the compound is hard, stable and reactive. Further, Z-3-(4-bromophenyl)-3-chloroacrylaldehyde also exhibited significant antibacterial activity against both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) with a zone of inhibition of 13 ± 1 mm against E. coli and 14 ± 1 mm against S. aureus and the MIC value was found to be 0.55 mg/mL against S. aureus and 1.1 mg/mL against E. coli. The integration of experimental and theoretical approaches in this study enhances the understanding of the versatile applications of BCA across various fields.

Novel short Agave americana based biocomposite and nanobiocomposites for automotive applications

Short fibers of Agave Americana (AA) was extracted from its plant leaf, was chemically treated with Ac2O, HCOOH, H2O2, KMnO4 and NaOH, and then characterized by Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), thermo-gravimetric/differential thermo-gravimetric (TGA/DTG), and field emission-scanning electron microscopy (FE-SEM). PVA stabilized copper nanoparticles from chemical reduction method was characterized using field emission-scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDAX), powder X-ray diffraction (PXRD), Dynamic light scattering analysis (DLS), UV–visible absorption spectroscopy, Fourier Transform infrared (FT-IR) spectroscopy and Thermogravimetric analysis/differential thermogravimetry (TGA/DTG). Bio-composites (AA + Polyester Resin (PE) and hybrid nano bio-composites (AA + Polyester Resin (PE) + Cu) were prepared from the untreated and treated AA fibers and further characterized. The synergistic effect of chemical treatment on morphological (SEM), thermal (TGA/DTG), mechanical properties (flexural, tensile, impact and compressive strength) followed by % water absorption were examined. The average surface roughness values (Ra) of chemical treated fiber was identified to be in decreasing manner along with compression strength of biocomposite in the order of untreated (10.74 μm, 44.01 MPa) > NaOH (8.55 μm, 45.07 MPa) > HCOOH (3.49 μm, 24.10 MPa) Ac2O (3.24 μm, 22.10 MPa) > H2O2 (2.51um, 17.9 MPa) > KMnO4 (1.52 μm, 15.1 MPa) treated fibers. Subsequently, the addition of 2s@PVA led to reverse the order namely, the compressive strength of the bionanocomposites were Untreated (10.74 μm, 9.0 MPa) < NaOH (8.55 μm, 0.1 MPa) < HCOOH (3.49 μm, 3.6 MPa) < Ac2O (3.24 μm, 7.6 MPa) < H2O2 (2.51um, 13.3 MPa) < KMnO4 (1.52 μm, 44.1 MPa) treated fibers. Similarly, the biocomposite where the fibres were treated with NaOH, HCOOH were more rough and had, good interconnection between fiber/PE matrix along with enhanced mechanical properties. On addition of nanobiocomposite, only KMnO4 treated fiber composite possed significant mechanical properties. Therefore, mixing CuNPs@PVA with KMnO4 treated fibers led to significant boost to the mechanical properties and minimised the % water absorption properties when compared to the untreated AA/PE biocomposites. The KMnO4 treatment of the AA fiber and addition of copper nanoparticles caused the enhancement of thermal properties, tensile strength and flexural strength. But, these nanobiocomposites were observed to have low impact strength; while, H2O2 treated nanobiocomposites had highest impact strength. The chemical treatment of the AA fiber with NaOH, Ac2O and KMnO4 developed the water resistance of the respective biocomposites. All the nanobiocomposites with chemically treated AA fibers (except Ac2O) were found to have high water resistance. So, they can be used in automotive industry for non-structural applications.