Bathochromic Research Articles

New 2-pyridone-based donor-acceptor dyes: the effect of the donor group position, type of π-linker and acid-base characteristics of the medium on the photophysical properties.

A series of novel donor-acceptor pyrid-2-ones was synthesized. The influence of the donor group on the photophysical properties of chromophores in solution was shown by varying the methoxy group position in the electron-rich aromatic ring. The effect of the π-linker was also demonstrated by the comparison of the D-π-A pyridone with its spacer-free analogue (D-A) and with the chromophore bearing an additional thiophene bridge (D-π-π-A). It was found that the presence of a π-linker plays a crucial role in the implementation of an intramolecular charge transfer (ICT) from the donor aryl moiety to the pyridone acceptor. Thus, for the synthesized D-A, D-π-A and D-π-π-A derivatives, the photoluminescence quantum yield in DMSO solution decreases from 56.8 to 4.3 and 3.5%, respectively, along with a strong bathochromic shift both for absorption (66 nm) and emission (162 nm) bands. Also, the possibility of shifting the equilibrium in DMSO solution towards either the pyridone form or the anionic form by the addition of a strong acid (TFA) and base (DBN) respectively was shown. Drastic changes in the photoluminescence of the solutions showed prospects for the application of the synthesized donor-acceptor pyridone derivatives as naked-eye acid-base indicators in organic media.

Solvatochromic shifts and solvent effects on the electronic and transport behaviour of 1-Chloro Adamantane

Solvent influence on the photophysical and electronic properties of 1-Chloro Adamantane (CAD) are investigated using experimental and computational methods. Measured UV–vis absorption of CAD in various solvents exhibits substantial solvatochromatic shifts with respect to the solvent polarity. As a result of this, optical absorption of CAD undergoes the bathochromic shifts in the nonpolar solvents and hypsochromic shifts in the polar solvents with respect to polarity. Theoretical computations of EOM-CCSD and CIS quantum chemical methods calculated by means of SMD solvation model demonstrate the solvent influence on the electronic structure of CAD which are in good agreement with the experimental results. Computed results show prominent solvation effect on Lewis and non-Lewis occupancies. Large excited state dipole moment of the CAD in various solvation suggests excited states are more polarized than the ground state. In addition to this, molecular polarizabilities and energies of HOMO and LUMO show dominant solvent effects on the chemical reactivity of the CAD upon solvation. This solvent specific behaviour of CAD finds applications in optical filters with its significant hydrophobic nature.

Advancing fluoride (F–) detection: Exploring the potential of digital color analysis with a novel thiourea receptor

This study aimed to explore a novel colorimetric detection method for fluoride using spectroscopic and digital analysis techniques. Thiourea compound synthesized from p-phenylenediamine and 4-nitrophenyl isothiocyanate was used as a receptor, with the NH group playing the role of a binding site to enhance the colorimetric detection process. This method facilitated visual detection by the naked eye and offered selectivity for fluoride ions. The result showed that there was a significant color change response, shifting from colorless to orange when fluoride was detected using the thiourea receptor. In this context, the color change was characterized by a bathochromic shift observed with UV–Vis spectrophotometry and quantified through high Euclidean Distance (ΔE) value of RGB color characteristics in digital analysis. Furthermore, the thiourea-based fluoride detection method had a low detection limit of 1.4 µM for spectroscopic analysis and 1.7 µM for digital analysis, along with a high recovery rate. These results affirmed the significance of spectroscopic and digital analyses using the thiourea receptor as a promising alternative for the rapid on-site detection of fluoride in real environmental samples.

Linear Extension of Carbaporphyrin Chromophores: Synthesis, Protonation, and Metalation of Anthro[2,3-b]carbaporphyrins: Evidence for 30π-Electron Aromatic Circuits in a Palladium(II) Complex.

Acid-catalyzed condensation of a naphtho[2,3-f]indane dialdehyde with a tripyrrane, followed by an oxidation step, afforded an anthro[2,3-b]-21-carbaporphyrin. The presence of a fused anthracene unit induced minor bathochromic shifts and did not significantly affect the aromatic characteristics of the carbaporphyrin core. Protonation led to the formation of a monocation with similar diatropic properties, but the dication generated in the presence of a large excess of trifluoroacetic acid had a weakened Soret band absorption and a broad absorption at 754 nm. Nucleus-independent chemical shift (NICS) calculations indicate that the dication is only weakly aromatic and possesses a 32-atom 30π electron delocalization pathway. Alkylation with methyl iodide and potassium carbonate gave a 22-methyl derivative that reacted with palladium(II) acetate to afford an aromatic palladium(II) complex. Upon heating, the methyl group migrated from the nitrogen to the internal carbon atom and the resulting complex exhibited diminished aromatic character. A comparison with related carbaporphyrin complexes without ring fusion or with benzo- or naphtho-fused units demonstrated that the diatropic character decreased with increasing conjugation. NICS calculations and anisotropy of induced current density (AICD) plots confirmed this trend and showed that the remaining aromatic properties of the anthrocarbaporphyrin complex were due to a 30π electron circuit that extends around the entire anthracene unit.

Perturbations on Oxybiotin Leading to Biotin. A DFT Treatment

In the present computational study, conversion of oxybiotin to biotin by means of oxygen to sulfur replacement has been investigated within the restrictions of density functional theory at the level of B3LYP/6-31++G(d,p). Both of the molecules have not only exothermic heat of formations but also favorable Gibbs free energy of formation values at the standard state. They are electronically stable. Various quantum chemical data accompanying the perturbation considered have been collected and discussed including UV-VIS spectra. The oxygen to sulfur replacement highly affects not only the distribution of molecular orbital energy levels but also the energies of the molecular orbitals in such a way that going from oxybiotin to biotin the HOMO energy level raises up but the LUMO decreases. The both occur at unequal extents thus biotin exhibits some bathochromic effect compared to oxybiotin.

An efficient end-capped engineering of pyrrole-based acceptor molecules for high-performance organic solar cells.

Various innovative molecules have been designed and explored for use in organic photovoltaics. In this study, we devised novel molecules (KZ1-KZ7) specifically for organic solar cells (OSCs). The newly formulated acceptor compounds possess a lower bandgap (Eg = 1.85-2.02), along with bathochromic shift (λmax = 713-788 nm) compared to the reference (Eg = 2.04 eV and λmax = 774 nm). Moreover, the FMO results identified the distinct charge transfer from HOMO to LUMO, which was strongly corroborated by the TDM maps. Similarly, the new designed molecules show less excitation energy (Ex = 1.31-1.54(gas)) than reference (Ex = 1.72). Likewise, all designed molecules (KZ1-KZ7) have demonstrated an analogous open circuit voltage (Voc) with the donor polymer PTB7-Th. All seven designed molecules (KZ1-KZ7) exhibited more fill factor ranging from 97.08 to 97.29 than reference 95.25 and PCE of between 8 and 20% at short circuit current densities of 9, 12, and 15 mA cm-2. Overall, the findings support that designed molecules can be potential molecules for future practical applications. Geometric calculations were conducted with Gaussian 09W software, and the findings were visualized using Gauss View software. DFT and TD-DFT were employed to evaluate various parameters for R and designed molecules (KZ1-KZ7). Firstly, four functionals including B3LYP, CAM-B3LYP, MPW1PW91, and ωB97XD with 6-31G(d,p) DFT level were applied to R to decide the best level for results. After appropriate analysis, the MPW1PW91/6-31G(d,p) was selected for further examination by comparing the experimental and DFT-based absorption graphs of R. External and internal reorganization energy are the two main factors contributing to reorganization energy. External energy refers to changes in external environment, while internal energy deals with information related to internal geometrical symmetry or the internal environment. The effect of outside factors or external reorganizational energy is omitted because it creates too little change.

The structure of anthocyanins and the copigmentation by common micromolecular copigments: A review

Under natural physiological conditions, anthocyanins can keep bright and stable color for a long time due to the relatively stable acid-base environment of plant vacuoles and the copigmentation from various copigment substances, such as polyphenols, nucleotides, metallic ions and other substances. Therefore, the copigmentation caused by copigments is considered an effective way to stabilize anthocyanins against adverse environmental conditions. This is attributed to the covalent and noncovalent interactions between colored forms of anthocyanins (flavylium ions and quinoidal bases) and colorless or pale yellow organic molecules (copigments). These interactions are usually manifested in both hyperchromic effect and bathochromic shifts. In addition to making anthocyanins more stable, the copigmentation also could make an important contribution to the diversification of their tone. Based on the molecular structure of anthocyanins, this review focuses on the interaction mode of auxochrome groups or copigments with anthocyanins and their effects on the chemical and color stability of anthocyanins.

MoS2 nanoflower-Indocyanine green composite for enhanced optical imaging capabilities

ABSTRACT To enhance the efficiency of painless targeted nanotherapies, integrating optical imaging capabilities into nanoplatforms is gaining momentum. Our study presents a cost-effective synthesis of MoS2 nanoflower (MNF) and Indocyanine green (ICG) composites (MNF-ICG) using a physical method based on van der Waals interactions. MNF, prepared via the hydrothermal method, underwent characterization through UV-vis, FTIR, and fluorescence spectroscopy, while FESEM and XRD techniques were employed to analyse morphology and structural phase. Through electrostatic interaction, ICG was absorbed onto the MNF surface. The resulting MNF-ICG demonstrated exceptionally high optical absorbance across a broad NIR spectra, facilitating longer-wavelength photothermic imaging with increased penetration depth. In comparison to MNF alone, the composite significantly enhanced the photothermal imaging sensitivity of nanoplatforms, exhibiting notable bathochromic and hyperchromic shifts in fluorescence intensity. This innovative approach holds promise for advancing nanotherapeutics with improved optical imaging capabilities.

Tautomers of 2,4-dihydro-3H-1,2,4-triazol-3-one and their Composites with NTO - A DFT Treatment

In the present density functional study, some tautomers of 2,4-dihydro-3H-1,2,4-triazol-3-one (1,2-dihydro-1,2,4-triazol-3-one) and their composites formed with NTO have been considered within the constraints of the density functional theory and the basis set employed (B3LYP/6-311++G(d,p)). The triazolone considered is the precursor of NTO in various methods. It may exhibit 1,3-proton tautomerism. Various energies, QASR, quantum chemical and spectral properties have been harvested and discussed. All the considered species have exothermic heat of formation and favorable Gibbs free energy of formation values at the standard states and they are stable electronically. Although most of the composites considered exhibit a directed interaction between their partners, one of them possesses perpendicular (T-type) orientation. Certain hydrogen bondings between the tautomers and NTO occur at different extents, depending on the particular tautomer involved in the composite. Both of the components have hydrogen bond donor and acceptor properties except composite NTO+T2, in which the tautomer is the hydrogen bond donor and NTO is the acceptor. The tautomers absorb in the UV region of the spectrum like NTO, whereas in all the composites appreciable changes in the appearance of the spectra happen and certain degree of bathochromic effect occurs as compared to the respective spectra of the partners.

Comparative phytochemical study of white poplar (<i>Populus alba</i> L.) and black poplar (<i>Populus nigra</i> L.)

Aim – to conduct a comparative phytochemical study of leaves, wood buds, shoots, bark of two representatives of the genus poplar – white poplar and black poplar.
 Material and methods. For the experiment, we have chosen leaves, wood shoots, buds, bark of black poplar (Populus nigra L.), white poplar (Populus alba L.) and also reference standards (RS). The thin-layer chromatography was carried out on the plates Sorbfil-PTSH-AF-A-UV in the systems n-butanol-acetic acid-water (4:1:2) and chloroform-ethyl alcohol-water (25:18:2). The spectrophotometry was carried out on a Specord 40 spectrophotometer (Analytik Jena) in cuvettes with a layer thickness of 10 mm in the wavelength range from 190 to 500 nm. The comparison solution was ethyl alcohol of 96% concentration.
 Results. In the water-alcohol extracts of the leaves of poplar species the presence of rutin and other phenolic compounds was detected. Pinostrobin and pinocembrin were observed in wood shoots, buds and bark of the plants. The bathochromic shift of the long-wavelength line in the ultraviolet spectra of the studied extracts solutions indicated the presence of flavonoids.
 Conclusion. In all cases, flavonoids made the greatest contribution to the absorption curves of the spectra, in particular: flavanones (pinocembrine, pinostrobin, and others), and phenylpropanoids (caffeic acid and other cinnamic acids). The leaves, wood shoots and buds of the plants contained substances of a phenolic nature, including flavonoids. The composition of the bark of the white poplar was mainly represented by phenolic compounds – phenylpropanoids and simple phenols.

Merocyanines form bacteriorhodopsins with strongly bathochromic absorption maxima

There is a need to shift the absorbance of biomolecules to the optical transparency window of tissue for applications in optogenetics and photo-pharmacology. There are a few strategies to achieve the so-called red shift of the absorption maxima. Herein, a series of 11 merocyanine dyes were synthesized and employed as chromophores in place of retinal in bacteriorhodopsin (bR) to achieve a bathochromic shift of the absorption maxima relative to bR’s λmaxa\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\lambda }_{\\mathrm{max}}^{a}$$\\end{document} of 568 nm. Assembly with the apoprotein bacterioopsin (bO) led to stable, covalently bound chromoproteins with strongly bathochromic absorbance bands, except for three compounds. Maximal red shifts were observed for molecules 9, 2, and 8 in bR where the λmaxa\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\lambda }_{\\mathrm{max}}^{a}$$\\end{document} was 766, 755, and 736 nm, respectively. While these three merocyanines have different end groups, they share a similar structural feature, namely, a methyl group which is located at the retinal equivalent position 13 of the polyene chain. The absorption and fluorescence data are also presented for the retinal derivatives in their aldehyde, Schiff base (SB), and protonated SB (PSB) forms in solution. According to their hemicyanine character, the PSBs and their analogue bRs exhibited fluorescence quantum yields (Φf) several orders of magnitude greater than native bR (Φf 0.02 to 0.18 versus 1.5 × 10–5 in bR) while also exhibiting much smaller Stokes shifts than bR (400 to 1000 cm−1 versus 4030 cm−1 in bR). The experimental results are complemented by quantum chemical calculations where excellent agreement between the experimental λmaxa\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\lambda }_{\\mathrm{max}}^{a}$$\\end{document} and the calculated λmaxa\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\lambda }_{\\mathrm{max}}^{a}$$\\end{document} was achieved with the second-order algebraic-diagrammatic construction [ADC(2)] method. In addition, quantum mechanics/molecular mechanics (QM/MM) calculations were employed to shed light on the origin of the bathochromic shift of merocyanine 2 in bR compared with native bR.Graphical abstract

Supramolecular complex of tetracationic porphyrin with acyclic cucurbituril-like container induces quantitative singlet oxygen generation. Phototoxicity studies in vitro in MCF-7 human breast cancer cells

Singlet oxygen generation by porphyrin-based photosensitizers is one of the main strategies used in the photodynamic therapy of cancerous lesions. In this work, we report that the complexation of tetracationic 5,10,15,20-tetrakis(N-methylpiridinium-4-yl)porphyrin (TMPyP) with an acyclic cucurbituril-like container denominated M2C4 achieves quantitative generation of singlet oxygen. The complexation was studied by isothermal titration calorimetry, revealing a highly favored binding event controlled by enthalpic contributions, a stoichiometry of 1:1 and a high binding constant (K = (1.7 ± 0.2) × 107 M−1). Photophysical studies of the complex showed bathochromic shifts in the absorption bands, increased fluorescence emission quantum yield and lengthened fluorescence lifetime. Nonetheless, fluorescence emission was minor, being intersystem crossing with the consequent generation of singlet oxygen the main deactivation pathway for the excited state. All these properties were compared with the previously reported TMPyP and cucurbit[7]uril (CB[7]) complex, which showed a superiority of the acyclic complex in terms of quantum efficiencies. Phototoxicity studies in a breast cancer cell line (MCF-7) cultured in vitro, showed that the TMPyP@M2C4 complex is unable to enter the cells even after a 24 h incubation period. However, this issue could be circumvented by encapsulating the complex into liposomes which delivered the complex to the cells efficiently. Overall, this strategy showed good potential for a highly efficient photodynamic treatment using the TMPyP@M2C4 complex in liposomal formulations.

Versatile Thermally Activated Delayed Fluorescence Emitters via Non‐conjugated Extension Strategy Enabling OLEDs with Efficiency Over 37%

AbstractIn recent years, thermally activated delayed fluorescence (TADF) materials with high horizontal dipole ratios (Θ//) have attracted enormous attention in constructing high‐efficiency organic light–emitting diodes (OLEDs). However, the common strategy to improve Θ// based on extending π‐conjugation tends to induce bathochromic emission shift, and emitters with Θ// exceeding 90% are rarely reported. Herein, a non‐conjugated extension strategy is developed to promote molecular horizontal dipole orientation. By simply modifying the spiro‐acridine with extra 9‐phenylcarbazole groups, two high‐efficiency and versatile TADF emitters 36DPCZSFAC‐TRZ and 36DPCZSFAC‐PYPM are constructed without bathochromic emission shift, and state‐of‐the‐art ultra‐high Θ// of 92% and 96% are achieved, respectively. More fascinatingly, due to the special spiro molecular structures, the TADF emitters hold distinguished merits of aggregation‐induced emission property, near unitary photoluminescence quantum yields, fast reverse intersystem crossing rates, and enhanced charge‐carrier transport property, which enable outstanding external quantum efficiency values of up to 22.1/20.9% and 37.4/34.2% in non‐doped/doped OLEDs for 36DPCZSFAC‐TRZ and 36DPCZSFAC‐PYPM, respectively, demonstrating their great potentials in the fabrication of high‐efficiency OLEDs.

Varied optical features and mechanofluorochromism in dicyanovinyl- vs. cyanoacrylicacid-linked twisted π-conjugates: A potential reusable platform for security applications

The dicyanovinyl-linked π-conjugates [DCV, =C(CN)2] are well identified as a stimuli/environment-sensitive fluorophore, while cyanoacrylic acid (CAA) -linked π-conjugates are hardly found. This study focuses on the diversity of solvatochromic, AIE- and mechanofluorochromic (MFC) features between DCV and CAA-linked conformationally twisted small π-conjugates. The creation of MFC-active smart molecules by tuning functionality has received considerable attention owing to its versatile applicability. While DCV-linked fluorophore TCN displays an impressive solvatofluorochromic property, CAA-linked analog TCNA showed no trend due to inter/intramolecular H-bonding. The TCN revealed AIE and a reversible MFC feature upon grinding with a significant bathochromic shift of 51 nm. Moreover, a 32 nm absorption shift was visually detected under ambient light after applying mechanical force (grinding). The non-AIEgen TCNA is emissive in the solid state but exhibited no emission/absorption shift after grinding. All the observed facts were supported by interpreting the molecular structures, crystal packing, powder X-ray diffraction data, and differential scanning calorimetric (DSC) studies. In addition, the DFT/TDDFT calculations were performed to support these outcomes. Finally, TCN is realized as a favorable platform for security writing/piezo patterning for anticounterfeiting applications.

D- π-A azo dyes bearing thiazole-diphenylamine units: Synthesis, photophysical and molecular structure properties, and use for dyeing of polyester fabrics

Herein, six new thiazole-dipehenylamine-based azo dyes containing azo and thiazole bridges and diphenylamine donor with different donor/acceptor groups were synthesized. All the synthesized dyes were characterized by FT-IR, NMR and HRMS analyses. The structure of (E)-N-methyl-4-((thiazol-2-yl)diazenyl)-N-phenylaniline (4) was conclusively confirmed by single crystal X-ray diffraction analysis. Photophysical studies were performed in different solvents with various polarity. Although the three synthesized compounds can be represented as potential azo-hydrazone tautomers only the azo form was observed in all solvents used. UV/vis spectroscopic studies showed that the color changed dramatically when the dyes contain a strong electron accepting nitro substituent. Moreover, after protonation of azo dyes, with the exception of the azo dyes with nitro group, a bathochromic shift was observed. The effects of protonation on the geometry and electronic structure of the compounds were studied, and the NLO properties were also investigated using DFT calculations. In addition, the thermal stability of the azo dyes was investigated using thermal gravimetry (TGA). Dyeing performance was evaluated with these dyes on polyester fabric in an aqueous medium. All dyes except dyes 3 and 6 showed good color fastness properties. Therefore, these compounds can be used as textile dyes for polyester fabrics.

Co-pigmentation of Pinotage anthocyanins with Cyclopia (honeybush) polyphenols in model wine solutions

Co-pigmentation of an anthocyanin-enriched fraction (AEF) of Pinotage wine with honeybush polyphenols (Cyclopia subternata extract and fractions enriched in specific polyphenols) was studied in model wine solutions. The hyperchromic effects and bathochromic shifts depended on the co-pigment sources and co-pigment/anthocyanin ratio. Fraction 2 (F2), enriched in xanthones (mangiferin and isomangiferin), produced the most pronounced co-pigmentation effect at a co-pigment/anthocyanin ratio of 15:1. Greater co-pigmentation effects were observed in model solutions at pH 3.0 (pH 3–4 evaluated) and in the absence of EtOH (0–16 % EtOH evaluated). During storage of solutions (AEF and/or F2) at 15 °C and 25 °C for 12 weeks, myrtillin, petunin, 3′,5′-di-β-D-glucopyranosyl-3-hydroxyphloretin and mangiferin concentrations decreased following first-order kinetics, while peonin and oenin degradation followed fractional-conversion kinetics. Polymeric anthocyanin formation followed zero-order kinetics. Reaction rates increased with an increase in storage temperature. The addition of F2 to the AEF solution produced a darker, more vivid colour and improved the colour stability, however, the yellow-orange colour of F2 and intensification of its colour during storage contributed to increasing red-orange hues. Further research is necessary to elucidate the effect of honeybush polyphenols on the colour and composition of a complete wine as it is more complex than model solutions.

Influence of Carboxymethyl Cellulose on the Green Synthesis of Gold Nanoparticles Using Gliricidia sepium and Petiveria alliacea Extracts: Surface-Enhanced Raman Scattering Effect Evaluation.

Gold nanoparticles (AuNPs) were synthesized and stabilized using ecological strategies: the extracts of the leaves of the plants Gliricidia sepium (GS) and Petiveria alliacea (PA) reduced the metallic Au ions to AuNPs. The AuNPs were analyzed as surface-enhanced Raman scattering (SERS) substrates for pyridoxine detection (vitamin B6). UV-vis spectroscopy was carried out to assess the stability of the AuNPs. As a result, absorption bands around 530 and 540 nm were obtained for AuNPs-PA and AuNPs-GS, respectively. Both cases associated it with localized surface plasmon resonance (LSPR). In the final stage of the synthesis, to stabilize the AuNPs, carboxymethyl cellulose (CMC) was added; however, LSPR bands do not exhibit bathochromic or hypsochromic shifts with the addition of CMC. Transmission electron microscopy (TEM) micrographs show relatively spherical morphologies; the particle diameters were detected around 7.7 and 12.7 nm for AuNPs-PA and AuNPs-GS, respectively. The nanomaterials were evaluated as SERS substrates on pyridoxine, revealing an intensification in the vibrational mode centered at 688 cm-1 associated with the pyridinic ring. Complementarily, different density functional theory functionals were included to obtain molecular descriptors on the Aun-cluster-pyridoxine interaction to study the SERS behavior.

Experimental and computational study of annealed nickel sulfide quantum dots for catalytic and antibacterial activity

This research investigates the hydrothermal synthesis and annealing duration effects on nickel sulfide (NiS2) quantum dots (QDs) for catalytic decolorization of methylene blue (MB) dye and antimicrobial efficacy. QD size increased with longer annealing, reducing catalytic activity. UV–vis, XRD, TEM, and FTIR analyses probed optical, structural, morphological, and vibrational features. XRD confirmed NiS2's anorthic structure, with crystallite size growing from 6.53 to 7.81 ​nm during extended annealing. UV–Vis exhibited a bathochromic shift, reflecting reduced band gap energy (Eg) in NiS2. TEM revealed NiS2 QD formation, with agglomerated QD average size increasing from 7.13 to 9.65 ​nm with prolonged annealing. Pure NiS2 showed significant MB decolorization (89.85%) in acidic conditions. Annealed NiS2 QDs demonstrated notable antibacterial activity, yielding a 6.15 ​mm inhibition zone against Escherichia coli (E. coli) compared to Ciprofloxacin. First-principles computations supported a robust interaction between MB and NiS2, evidenced by obtained adsorption energies. This study highlights the nuanced relationship between annealing duration, structural changes, and functional properties in NiS2 QDs, emphasizing their potential applications in catalysis and antibacterial interventions.

Synthesis and Evaluation of Molecularly Imprinted Nanoparticles for Detection and Quantification of Zolpidem In Human Plasma

AbstractIn response to the alarming rates of zolpidem abuse, this study presents a pioneering approach utilizing molecularly imprinted nanoparticles (MIPs) in conjunction with high‐performance liquid chromatography (HPLC) for the selective detection of zolpidem. The rational choice of zolpidem as the target analyte stems from its widespread misuse and clinical significance. The MIPs were prepared using the precipitation polymerization method, resulting in monodispersed nanoparticles with a size of approximately 258.8 nm. Fourier Transform Infrared (FTIR) analysis confirmed the successful incorporation of zolpidem into the MIPs, designed with tailored cavities for zolpidem recognition. Moreover, incorporating the bathochromic shift phenomenon reaffirms the successful imprinting procedure. The rebinding studies showed that MIPs were highly efficient in adsorbing zolpidem from the solvent, with more than 95 % of the drug recovered after multiple cycles. The selectivity study demonstrated the MIPs′ preference for zolpidem over another drug, diazepam. The MIPs′ successful separation of zolpidem from spiked human plasma samples further validates their potential for practical applications, such as clinical toxicology. This research showcases the potential of MIPs coupled with HPLC as a powerful tool for accurate zolpidem quantification, holding great promise for combating drug abuse and advancing analytical methodologies for pharmaceutical analysis.

Green approach to new library of 1,8-naphthalimide fluorophores employing C-C and C-N cross coupling reactions by novel, durable, and reusable magnetic nanocatalyst bearing nickel (0) complex of 1,10-phenanthroline

The novel light cayn to yellow fluorescent 1,8-naphthalimide-based compounds with benzothiophene, benzofuran, aryl, and amino substituent at the C-4 position were successfully synthesized in excellent yields (up to 97 % yield) via the catalysed Suzuki coupling and carbon–nitrogen cross coupling reactions using a novel heterogeneous super nanomagnetic Ni-catalyst system bearing fortified 1,10-phenanthroline ligand (Fe3O4@SiO2-Phen-Ni(0)) under mild conditions. The structure of synthesized magnetic nanocatalyst was identified by FT-IR, XRD, FESEM, DLS, TEM, VSM, TGA-DSC, EDX, mapping images, ICP, and UV–Vis techniques, which exhibited high efficiency in the synthesis of these C-4 π-conjugated and amino fluorophore 1,8-naphthalimide materials with low Ni-contamination. The nanocatalyst with the aid of an external magnet could be easily recovered and reused for up to nine consecutive runs without significant decline in its activity. UV–Vis absorption and fluorescence emission spectrum of these derivatives were collected. All these compounds can emit light cay, greenish-yellow or yellow emission and show a large Stokes shift (νa-νf up to 8900 cm−1), longer λ emission (λem up to 541 nm), and fluorescence quantum yield (Qf) (up to 0.89) due to the extended conjugation system. The provided data of Suzuki derivatives reveal the highest Qf and λem in EtOH solvent, and 4-amino-1,8-naphthalimide derivatives exhibit, the highest Qf data in DCM solvent, and the largest emission wavelength in acetonitrile, and the highest data of Stokes shift in EtOH. Furthermore, the positive solvatochromic behavior, corresponding to bathochromic shift with increasing solvent polarity, in new C4-aryl/ heteroaryl/ and amino 1,8-naphthalimide frameworks was shown.