UV Vis Absorption Spectra Research Articles

Developing a novel radiosensitive metal ion-loaded PVA/NBT film as medical low-dose X-ray dosimeter

The hazards associated with ionizing radiation exposure has spurred the advancement of reliable and precise dosimetry techniques. Currently, there still lacks a viable and efficient dosimetry methods for measuring radiation expo-sure within low dosage ranges. This raises a concern in certain domains, such as radiodiagnostics and practitioners that employ low-dose X-ray radiation. Hence, this study aims to produce PVA/NBT film dosimeters that are capable in effectively detecting low dosages of X-ray radiation. Moreover, PVA/NBT films loaded by various metal ions will also be studied. The films were synthesized by the solvent casting method. The films were subjected to X-ray irradiation with a dosage ranging from 0 to 2.626 mGy. The films were further examined through EDX analysis, UV–Vis spectroscopy, optical density measurement, FTIR spectroscopy, and SEM analysis. It was observed that X-ray radiation exposure caused a broadening in the UV–Vis absorbance spectrum, which enhances its light absorption capability and making it more opaque. Furthermore, the careful selection of metal ion enhanced the film's ability in detecting X-ray radiation. Silver-loaded films were proven to significantly enhance the linearity and sensitivity of the PVA/NBT dosimeter film. These findings showed that silver-loaded PVA/NBT films exhibit a promising prospect for further applications in the domain of medical radiation.

Design, synthesis, crystal structure and anticancer activity of organotin(IV)-rhein carboxylates

Two new rhein-organotin complexes Ph3Sn(O2CC14H7O4) (RS01) and Cy3Sn(O2CC14H7O4) (RS02) were synthesized and characterized by elemental analysis, IR, 1H NMR, 13C NMR, 119 Sn NMR, X-ray crystallography and thermo-gravimetric analysis. Both complexes has a triclinic crystal system P-1 space group and one-dimensional supramolecular chain structure. The MTT results demonstrated that rhein's anticancer activity was effectively increased by introducing organotin, RS01 and RS02 exhibited excellent anticancer activity in vitro, significantly superior to cisplatin and mitoxantrone. Interestingly, despite the fact that RS01 and mitoxantrone share the same 9,10-anthraquinone scaffold structure, RS01 not only showed high anticancer activity but also much lower nephrotoxicity than mitoxantrone. Flow cytometry showed that RS01 could significantly induce cell apoptosis and arrest cell cycle in G2 phase. Molecular docking and UV–Vis absorption spectra suggested that RS01 may be intercalation with DNA. Furthermore, western blot results showed that RS01 activated the DNA damage critical protein γ-H2AX and regulated the expression level of the mitochondrial apoptotic pathway critical protein (Bax/Bcl-2). Thus, RS01 induced cell death may be mediated through DNA damage and mitochondrial pathways. As a result, RS01 has significant development and application potential as an anticancer agent.

Optimizing dyeing parameters for sustainable wool dyeing using quinoa plant components with antibacterial properties

This study focuses on the sustainable utilization of Quinoa plant components, particularly its leaves, as a waste agricultural material for natural dyeing applications. Two distinct Quinoa genotypes, Titicaca and Giza, were selected for their natural dyeing properties. UV-VIS absorption spectra of Quinoa colorant extracts provided insights into their chemical composition, revealing distinctive peaks indicative of betalains (400–450 nm), chlorophyll (600–650 nm), carotenoids (400–500 nm), and aromatic amino acids (250–280 nm). Wool samples dyed with different plant parts such as flowers, leaves, and stalks exhibited distinct yellow hue, with leaves demonstrating the highest color strength. Metal mordants such as iron (II) sulphate, copper sulphate, and tin (II) chloride influenced color outcomes, highlighting their role in tailoring final appearance. Fastness properties of dyed wool samples were evaluated, with leaves showing moderate staining resistance and good light fastness. Additionally, antibacterial properties of leaves of Giza Quinoa variety were assessed, showing promising activity against Staphylococcus aureus. The antibacterial properties of fabrics dyed with the leaf extract by mordanting method with different metal salt mordants, particularly Fe, Cr, and Cu, exhibited significant enhancement. These results highlight the multifaceted benefits of Quinoa plant components in sustainable natural dyeing and textile applications, emphasizing their potential for eco-friendly practices in the textile industry.

Charge Transfer and Intersystem Crossing in Compact Naphthalenediimide-Phenothiazine Triads: Synthesis and Study of the Photophysical Property with Transient Optical and Electron Paramagnetic Resonance Spectroscopic Methods.

In order to obtain a long-lived charge separation (CS) state in compact electron donor-acceptor molecular systems, we prepared a series of naphthalenediimide (NDI)-phenothiazine (PTZ) triads, with phenylene as the linker between the donor and acceptor. Conformation restriction is imposed to control the mutual orientation of the NDI and PTZ units by attaching methyl groups on the phenylene linker to tune the electronic coupling between the donor and the acceptor. Moreover, the PTZ moiety was oxidized to sulfoxide to tune the ordering of the CS state and the 3LE state (LE: locally excited state). UV-vis absorption spectra indicate electronic coupling between NDI with the phenylene linker as well as the PTZ units, manifested by the appearance of a charge-transfer (CT) absorption band, whereas this coupling is devoid in the triads with conformation restriction imposed. Fluorescence is strongly quenched in the triads compared to the reference compound, indicating electron transfer upon photoexcitation. Femtosecond transient absorption spectra indicate that the CS takes 0.8 ps, and then the 3LE state is formed by charge recombination in 83 ps. Nanosecond transient absorption (ns-TA) spectra show that the 3NDI state was observed in nonpolar solvents such as cyclohexane (triplet state lifetime: 95.7 μs), whereas the CS state was observed in more polar solvents. The CS state lifetimes are up to 1.2 μs (in toluene). Time-resolved electron paramagnetic resonance spectra of the triads in toluene consist of two types of signals: CS states (narrower signals, ∼10 mT) and 3LE states (broader signals, ∼50 to 200 mT). In the spectra of the triads containing PTZ, the CS state signals dominate, whereas for the triads containing oxidized PTZ, the 3NDI signals (zero-field splitting D ≈ 2000 MHz) prevail, both observations being in agreement with the ns-TA spectral studies. The electron spin polarization phase pattern of the 3NDI states of the triads indicates that the intersystem crossing (ISC) mechanism is spin-orbit charge-transfer ISC. Considering the 3CS state as ion pairs, the electron-exchange energy (J) is determined to be -39 to -59 MHz, and the electron spin dipolar interaction is 83-92 MHz.

Synthesis of silver (Ag) nano/micro-particles via green process using Andrographis paniculata leaf extract as a bio-reducing agent

In this work silver nano/micro-particles have been synthesized using sambiloto (Andrographis paniculata) plant extract as a bio-reducing agent. The effects of different plant extract concentrations, AgNO3 precursor concentrations, and reaction time on the synthesized silver nano/micro-particles were investigated. The silver nano/micro-particles samples were then analyzed using UV-Vis spectrophotometer (UV-Vis), X-Ray Diffractometer (XRD), Field Emission Scanning Electron Microscopy (FESEM), Particle Size Analyzer (PSA), and Fourier Transform Infra-Red (FTIR) spectroscopy. The UV-Vis absorbance spectrum of the colloid silver nano/micro-particles exhibited that all samples had absorbance peaks at a wavelength around 450 nm, confirming the formation of silver nano/micro-particles. It was also found that the UV-Vis absorbance peak of the silver nano/micro-particles inversely increased with decreasing AgNO3 solution concentration. Whereas, the higher the sambiloto extract concentration the higher the UV-Vis absorbance peaks. The UV-Vis absorbance peak increased with increasing synthesis time, suggesting that silver nano/micro-particles became more prominent. The UV-Vis absorbance peaks of the silver nano/micro-particles were about 0.0462, 0.0637, 0.0729, and 0.0936 at reaction time of 5, 10, 20, and 40 min, respectively. The XRD analysis result confirmed that the synthesized silver nano/micro-particles were in the form of nanocrystals with a face-centered cubic centered without any impurities. Additionally, the FESEM images showed that the silver nano/micro-particles had the primary particle size of 150-300 nm. There was the formation of some secondary particles with the size of about 0.7-1.5?m due to the agglomeration of primary particles. The particle size distribution analysis further confirmed the presence of primary and secondary particles. Meanwhile, the FTIR analysis confirmed the presence of four main peaks, linked to functional groups in the sambiloto extract and involved in the creation of silver nano/micro-particles.

Treatment of real carwash wastewater using high-efficiency and energy-saving electrocoagulation technique

This study focused on the treatment of actual wastewater from a car wash facility using electrocoagulation. The primary objective was to decrease chemical oxygen demand (COD) and eliminate turbidity by employing various electrodes such as Stainless Steel (SS) 304, Galvanized Iron (GI), and aluminum foil (α-Al) in a batch configuration. Several factors including contact time, current density, initial pH, and electrode material were examined to optimize process efficiency. The sludge generated during electrocoagulation was analyzed using Scanning Electron Microscopy/Energy-Dispersive X-ray Spectrometry (SEM-EDS). The results indicated that COD removal efficiency initially decreased between 30 and 60 min before improving. The data for COD, turbidity, and total phosphate reduction aligned well with the pseudo-first-order kinetic model, with R2 values of 0.275, 0.898, and 0.522, respectively. Minor variations were observed in pH, Total Dissolved Solids (TDS), Electrical Conductivity (EC), and alkalinity, while the temperature increased from 12 to 18.6 °C. Optimal removal efficiency for turbidity, total phosphate, and COD was achieved at pH = 6. The study demonstrated that higher current density resulted in enhanced COD reduction and turbidity removal. Chloride levels decreased with increasing applied current. The α-Al electrode exhibited superior performance compared to SS 304 and GI electrodes, with notable pH fluctuations during the process. UV–visible absorption spectra indicated differences in treated wastewater patterns based on the electrode utilized. SEM analysis revealed distinct characteristics of sludge produced by different electrodes. Energy and electrode consumption varied among the electrodes, with SS 304 displaying the lowest values.

Crystal structures, Hirshfeld surface analyses and optical properties of four new Cu(II)-based coordination polymers

Coordination polymers have been proven to be research hotspots for their fascinating structure and functional properties. In this work, four new Cu(II)-based CPs, namely [Cu(L)(H2O)]n (1), [Cu(L)(phen)(H2O)]·1.5H2O (2), {[Cu(L)(bimb)0.5]·H2O}n (3) and {[Cu(L)(dib)0.5(H2O)]·1.5H2O}n (4) [H2L=3-carboxy-1-(3′-carboxy-benzyl)-2-oxidopyridinium, 1,10-phenanthroline (phen), 1,4-bis-((1H-imidazol-1-yl)methyl)benzene (bimb) and 1,4-di(1H-imidazol-1-yl)butane (dib)], were synthesized under hydrothermal conditions. These four compounds show different structures defined by single-crystal X-ray diffraction. In addition, these compounds are characterized by powder X-ray diffraction (PXRD), infrared spectra (IR), elemental analyses, thermogravimetric analyses, Hirshfeld surface analyses and UV–vis absorption spectra.

Utilizing Pometia Pinnata leaf extract in microwave synthesis of ZnO nanoparticles: Investigation into photocatalytic properties

In this work, ZnO photocatalyst has been synthesized using matoa (Pometia pinnata) leaf extract under various microwave irradiation powers at 360, 540, and 720 Watts for 3 minutes on each. The UV-Vis absorption spectra of ZnO exhibited a peak in the ultraviolet region 300-360 nm. UV-Vis absorption analysis revealed a decrease in the band gap energy from 3.15 eV to 3.10 eV as the irradiation power increased. Field emission scanning electron microscopy (FESEM) images displayed spherical and nanoplatelet morphology with a decrease in particle size observed from 773 to 709 nm with increasing irradiation power. X-ray diffraction (XRD) analysis confirmed the hexagonal wurtzite structure of ZnO with crystallite sizes in the range of ~18-20 nm. The synthesized ZnO nanoparticles was successfully employed as a photocatalyst in 4-nitrophenol degradation, achieving the highest degradation percentage of 82.7% at 540 Watts with a corresponding reaction rate constant of 0.0126/min. In conclusion, the microwave-assisted synthesis of ZnO using on matoa leaf extract demonstrated significant potential for the degradation of organic pollutants, thereby contributing to water purification efforts.

Multi-spectral and docking assessments to explore the combination of an antiviral drug, entecavir with bovine serum albumin

Molecular interaction of entecavir (ETV) with the transport protein, albumin from bovine serum (BSA) was explored through multispectral and molecular docking approaches. The BSA fluorescence was appreciably quenched upon ETV binding and the quenching nature was static. The ETV–BSA complexation and the static quenching process were further reiterated using UV–visible absorption spectra. The binding constant (Ka) values of the complex were found as 1.47 × 104–4.0 × 103 M−1, which depicting a modarate binding strength in the ETV–BSA complexation. The experimental outcomes verified that the stable complexation was primarily influenced by hydrophobic interactions, hydrogen bonds and van der Waals forces. Synchronous and 3-D fluorescence spectral results demonstrated that ETV had significant impact on the hydrophobicity and polarity of the molecular environment near Tyr and Trp residues. Competitive site-markers displacement (with warfarin and ketoprofen) results discovered the suitable binding locus of ETV at site I in BSA. The molecular docking assessments also revealed that ETV formed hydrogen bonds and hydrophobic interactions with BSA, predominantly binding to site I (sub-domain IIA) of BSA.

Optimization of C/N co-doped TiO2 for enhancing photocatalytic denitrification of real waste brine under visible light: A reusable catalyst with an economical hole scavenger

Un-doped TiO2 (U-TiO2) and C/N co-doped TiO2 (CNT) with various C/N ratios were successfully synthesized for photocatalytic denitrification (PD) of real waste brine. To analyze the materials’ physicochemical characteristics, XRD, FESEM-EDX, elemental mapping, BET, and UV–Vis absorption spectra were utilized. Under visible light, the optimized CNT with the highest PD efficiency (>95 %) and the lowest band gap (2.6 eV) was immobilized on granular activated carbon(CNT/GAC) as a reusable catalyst. More than 98 % PD efficiency with 100 % N2 selectivity were achieved using glycerol, a waste product of the biodiesel manufacturing process, as an economical and eco-friendly hole scavenger (HS) substitute for formic acid as a conventional HS. In addition, the CNT/GAC became stable and active, even after five cycles.

Control of Photoinduced Charge Transfer Through Selective Cyanation of Spirofluorene‐Bridged N‐Heterotriangulenes

AbstractA series of selectively cyanated spirofluorene‐bridged N‐heterotriangulenes (N‐HTAs) with three to nine cyano groups are synthesized via a newly developed synthetic strategy. X‐ray crystallographic analysis of the compounds revealed a tripod‐like molecular shape with the fluorenyl moieties arranged in a perpendicular fashion around the nitrogen‐centered N‐HTA core. The solid state packing is found to be strongly influenced by the dipolar cyano functions. Under electrochemical conditions, the N‐HTA core is prone to undergo a reversible one‐electron oxidation toward the nitrogen‐centered radical cation, which becomes increasingly difficult as the number of the cyano acceptors, and consequently the ionization potential, increases. While a clear bathochromic shift is observed in the steady‐state UV–vis absorption spectra, the fluorescence behavior is complex and strongly dependent on the position and number of the cyano groups. The compound with six cyano functions at the fluorenyl flanks is unique within the series and shows a broad emission maximum at 499 nm and an unusually large Stokes shift of 10 171 cm−1. Time‐resolved absorption and fluorescence measurements, supported by quantum chemical calculations, identified this spectroscopic signature to originate from fast and robust photoinduced intramolecular charge transfer.

Bromo substituted aroylhydrazones: Synthesis, crystal structures, Hirshfeld surface analysis, 3D energy frameworks, DNA/BSA binding, and antimicrobial activity

Two bromo substituted aroylhydrazones such as 2-benzoylpyridine-4-bromobenzhydrazone (HBpB) and di-2-pyridyl ketone-4-bromobenzhydrazone (HDpB) were synthesized. The synthesized compounds have been characterized physicochemically using CHNS analysis, FT-IR, UV-vis absorption, 1H NMR and high resolution-mass spectra and the structures have been confirmed with single crystal X-ray diffraction technique. HBpB got crystallized in the monoclinic P21/c space group and the HDpB in the triclinic P1¯ space group. The supramolecular interactions present in the crystal system were studied with Hirshfeld surface (HS) analysis. The energy frameworks have been built by using different intermolecular interaction energies in order to study the stability of the molecule and determine the dominant energy type. The average interaction energy values for compounds HBpB and HDpB are found to be -280.4 and -327.2 kJ mol−1, respectively. Further, the nature of frontier orbitals and the stability of the compounds in the gas phase were theoretically analyzed, and the electrostatic potential surface diagram were plotted on optimized geometries. The binding potentials of HBpB and HDpB with DNA and BSA protein were investigated using spectroscopic, electrochemical, and in silico molecular docking methods. The results showed that HBpB has a higher binding affinity with both DNA and BSA compared to HDpB. Both HBpB and HDpB interact with DNA through a minor groove mode, while their binding to BSA involves mainly hydrophobic type. The ADMET analysis of compounds yielded favorable results for their potential use in pharmacological applications. When assessing the antibacterial capabilities of the tested samples, both the compounds showed good antimicrobial activities towards Klebsiella pneumonia, Bacillus Subtilis, Pseudomonas aeruginosa and Escherichia Coli.

Biochemical properties of novel Carbon nanodot-stabilized silver nanoparticles enriched calcium hydroxide endodontic sealer.

Calcium Hydroxide-based endodontic sealer loaded with antimicrobial agents have been commonly employed in conventional root canal treatment. These sealers are not effective against E. faecalis due to the persistent nature of this bacterium and its ability to evade the antibacterial action of calcium hydroxide. Therefore, endodontic sealer containing Carbon nanodots stabilized silver nanoparticles (CD-AgNPs) was proposed to combat E. faecalis. The therapeutic effect of CD-AgNPs was investigated and a new cytocompatible Calcium Hydroxide-based endodontic sealer enriched with CD-AgNPs was synthesized that exhibited a steady release of Ag+ ions and lower water solubility at 24 hours, and enhanced antibacterial potential against E. faecalis. CD-AgNPs was synthesized and characterized morphologically and compositionally by Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy (FTIR), and UV-Vis Spectroscopy, followed by optimization via minimum inhibitory concentration (MIC) determination against E. faecalis by broth microdilution technique and Cytotoxicity analysis against NIH3T3 cell lines via Alamar Blue assay. Calcium hydroxide in distilled water was taken as control (C), Calcium hydroxide with to CD-AgNPs (5mg/ml and 10mg/ml) yielded novel endodontic sealers (E1 and E2). Morphological and chemical analysis of the novel sealers were done by SEM and FTIR; followed by in vitro assessment for antibacterial potential against E. faecalis via agar disc diffusion method, release of Ag+ ions for 21 days by Atomic Absorption Spectrophotometry and water solubility by weight change for 21 days. CD-AgNPs were 15-20 nm spherical-shaped particles in uniformly distributed clusters and revealed presence of constituent elements in nano-assembly. FTIR spectra revealed absorption peaks that correspond to various functional groups. UV-Vis absorption spectra showed prominent peaks that correspond to Carbon nanodots and Silver nanoparticles. CD-AgNPs exhibited MIC value of 5mg/ml and cytocompatibility of 84.47% with NIH3T3 cell lines. Novel endodontic sealer cut-discs revealed irregular, hexagonal particles (100-120 nm) with aggregation and rough structure with the presence of constituent elements. FTIR spectra of novel endodontic sealers revealed absorption peaks that correspond to various functional groups. Novel endodontic sealers exhibited enhanced antibacterial potential where E-2 showed greatest inhibition zone against E. faecalis (6.3±2 mm), a steady but highest release of Ag+ ions was exhibited by E-1 (0.043±0.0001 mg/mL) and showed water solubility of <3% at 24 hours where E-2 showed minimal weight loss at all time intervals. Novel endodontic sealers were cytocompatible and showed enhanced antibacterial potential against E. faecalis, however, E2 outperformed in this study in all aspects.

Effect of Ho3+ Doping on Structural and Magnetic Properties of Multiferroic YbMnO3

Using the traditional solid-state reaction approach, multiferroic ceramics with the compositional formula Yb1−xHoxMnO3, where x = 0 to 0.4 with 0.1 variation were synthesized. The structural and magnetic properties of the prepared poly-crystalline samples Yb1−xHoxMnO3 were investigated to show the effect of higher magnetic moment Ho3+ ion over the Yb ion. X-ray diffraction was used to analyze the compound’s crystal structure and confirm that they have a hexagonal single-phase structure with a P6 3 cm space group. The presence of functional groups and their shifting to lower frequency regions were revealed by Fourier-transform infrared spectroscopy. UV–vis absorbance spectra were used to calculate the energy gap values, and the resultant data shows a decrease in band gap values with an increase in Ho3+ doping. Crystal deformation with the doping of Ho3+ was observed using Raman spectra. Room-temperature magnetic studies were used to reveal the paramagnetic nature of the samples and the increase in magnetic parameters due to the doping of the higher magnetic moment Ho3+ ion.

Individual quantification of ozone and reactive nitrogen species in mixtures by broadband UV–visible absorption spectra deconvolution

Ozone (O3), nitrogen oxides (NO x ), and reactive nitrogen species (RNS) play critical roles in atmospheric-pressure plasma applications. Although it is crucial to individually quantify these species to understand atmospheric-pressure plasmas and increase their effectiveness, the lack of reliable and cost-effective diagnostics makes this difficult for many researchers. To address this problem, we introduce a new deconvolution method of broadband ultraviolet–visible absorption spectra for the simultaneous measurement of eight species—O3, NO, NO2, NO3, N2O4, N2O5, HONO, and HNO3. Processing of broadband spectra enables deconvolution of similar cross-section profiles and measurement of high densities exceeding the instrumental limit. Novel correction processes enable accurate analysis despite incomplete cross-section data and utilize a priori chemical knowledge to ensure theoretically reasonable results. Two case studies test the efficacy of the method: NO2 and N2O4 equilibria, and reactive species produced by a surface dielectric barrier discharge. With an analysis time of 15–20 ms per spectrum, the measured densities agree well with other theoretical and experimental results, and detection limits on the order of ppmv were achieved with a short path length of 15 cm. This spectral analysis method will facilitate the real-time monitoring of O3, NO x , and RNS in many scientific research and industrial applications of atmospheric pressure plasmas.

Investigation of the Structural, Electrical, and Optical Properties of Co-Precipitation-Synthesized Aluminum-Doped ZnO Nanostructures

Abstract: This study examines the Structural, Electrical, and Optical characteristics of Zinc Oxide substituted with aluminum (AlxZn1-xO; x = 0, 0.02, 0.04, 0.06, 0.08). The coprecipitation technique is used to synthesize the powders, and X-ray diffraction (XRD) is used to analyze the powders' structural properties. Field Emission Scanning Electron Microscopy (FESEM) is used to study the morphological characteristics of the produced powders. The UV-visible absorbance spectrum (UV-Vis.) was used to assess the particles' optical characteristics. Using photoluminescence (PL) spectra, the effects of morphology on the optical and electrical characteristics of produced powders were examined. The XRD patterns verified that a single-phase hexagonal wurtzite structure formed for each sample. The powders' FESEM pictures reveal how, as the Al concentration increases, the particles' morphology alters from hexagonal to spherical. The synthesized samples have crystallite sizes between 19 and 26 nm. The predictable variations noticed with Al3+ concentration are consistent with Al3+ incorporation into the ZnO lattice, as confirmed by the UV-Vis spectroscopy measurements.

Synthesis, crystal structure and photophysical properties of a dinuclear MnII complex with 6-(di-ethyl-amino)-4-phenyl-2-(pyridin-2-yl)quinoline.

A new quinoline derivative, namely, 6-(di-ethyl-amino)-4-phenyl-2-(pyridin-2-yl)quinoline, C24H23N3 (QP), and its MnII complex aqua-1κO-di-μ-chlorido-1:2κ4 Cl:Cl-di-chlorido-1κCl,2κCl-bis-[6-(di-ethyl-amino)-4-phenyl-2-(pyridin-2-yl)quinoline]-1κ2 N 1,N 2;2κ2 N 1,N 2-dimanganese(II), [Mn2Cl4(C24H23N3)2(H2O)] (MnQP), were synthesized. Their compositions have been determined with ESI-MS, IR, and 1H NMR spectroscopy. The crystal-structure determination of MnQP revealed a dinuclear complex with a central four-membered Mn2Cl2 ring. Both MnII atoms bind to an additional Cl atom and to two N atoms of the QP ligand. One MnII atom expands its coordination sphere with an extra water mol-ecule, resulting in a distorted octa-hedral shape. The second MnII atom shows a distorted trigonal-bipyramidal shape. The UV-vis absorption and emission spectra of the examined compounds were studied. Furthermore, when investigating the aggregation-induced emission (AIE) properties, it was found that the fluorescent color changes from blue to green and eventually becomes yellow as the fraction of water in the THF/water mixture increases from 0% to 99%. In particular, these color and intensity changes are most pronounced at a water fraction of 60%. The crystal structure contains disordered solvent mol-ecules, which could not be modeled. The SQUEEZE procedure [Spek (2015 ▸). Acta Cryst. C71, 9-18] was used to obtain information on the type and qu-antity of solvent mol-ecules, which resulted in 44 electrons in a void volume of 274 Å3, corresponding to approximately 1.7 mol-ecules of ethanol in the unit cell. These ethanol mol-ecules are not considered in the given chemical formula and other crystal data.

Synthesis of non-modified near-infrared carbon dots for hypochlorite detection and cell membrane imaging

Devising carbon dots with long wavelength emission (red light or near infrared), high selectivity and good bio-compatibility is critical in fluorescence detection and imaging, but achieving this goal remains a great challenge. Herein, near-infrared emissive carbon dots (NIR-CDs) with obvious emission characteristic of 653 nm were synthesized through hydrothermally treatment of toluidine bule and gallic acid. Noticeably, the NIR-CDs exhibited excellent selectivity and sensitivity to hypochlorite (ClO−), and the limit of detection is as low as 42.7 nM. The selective recognition reaction between ClO− and the surface functional groups of NIR-CDs inhibits the fluorescence from NIR-CDs. The quenching mechanism was confirmed by fluorescence lifetime decays, FT-IR spectroscopy and UV–vis absorption spectra. More remarkably, the NIR-CDs have rich hydrophilic groups showed lower cytotoxicity, excellent bio-compatibility and specific cell membrane localization ability. The established spectrofluorometric method based on NIR-CDs has been used to determination of ClO− level in tap water sample, the recoveries were 97.7 %–103.3 %. In addition, the NIR-CDs also has been successfully applied for the imaging of cell membrane. The study provides a novel idea for developing NIR ClO− probe as well as cell membrane localization probe based on CDs, which present bright prospects in real water samples monitoring and cell membrane imaging.

The Role of Intraligand Charge Transfer Processes in Iridium(III) Complexes with Morpholine-Decorated 4'-Phenyl-2,2':6',2″-terpyridine.

To investigate the impact of the electron-donating morpholinyl (morph) group on the ground- and excited-state properties of two different types of Ir(III) complexes, [IrCl3(R-C6H4-terpy-κ3N)] and [Ir(R-C6H4-terpy-κ3N)2](PF6)3, the compounds [IrCl3(morph-C6H4-terpy-κ3N)] (1A), 4[Ir(morph-C6H4-terpy-κ3N)2](PF6)3 (2A), [IrCl3(Ph-terpy-κ3N)] (1B) and [Ir(Ph-terpy-κ3N)2](PF6)3 (2B) were obtained. Their photophysical properties were comprehensively investigated with the aid of static and time-resolved spectroscopic methods accompanied by theoretical DFT/TD-DFT calculations. In the case of bis-terpyridyl iridium(III) complexes, the attachment of the morpholinyl group induced dramatic changes in the absorption and emission characteristics, manifested by the appearance of a new, very strong visible absorption tailing up to 600 nm, and a significant bathochromic shift in the emission of 2A relative to the model chromophore. The emission features of 2A and 2B were found to originate from the triplet excited states of different natures: intraligand charge transfer (3ILCT) for 2A and intraligand with a small admixture of metal-to-ligand charge transfer (3IL-3MLCT) for 2B. The optical properties of the mono-terpyridyl iridium(III) complexes were less significantly impacted by the morpholinyl substituent. Based on UV-Vis absorption spectra, emission wavelengths and lifetimes in different environments, transient absorption studies, and theoretical calculations, it was demonstrated that the visible absorption and emission features of 1A are governed by singlet and triplet excited states of a mixed MLLCT-ILCT nature, with a dominant contribution of the first component, that is, metal-ligand-to-ligand charge transfer (MLLCT). The involvement of ILCT transitions was reflected by an enhancement of the molar extinction coefficients of the absorption bands of 1A in the range of 350-550 nm, and a small red shift in its emission relative to the model chromophore.

Integrated Solution for As(III) Contamination in Water Based on Crystalline Porous Organic Salts.

A stable crystalline organic porous salt (CPOSs-NXU-1) with 1D apertures has been assembled by the solvothermal method, which shows high-sensitivity "turn-on" fluorescence detection and large-capacity adsorption of As(III) ions in water. The detection limits, saturated adsorption capacity, and removal rate of CPOSs-NXU-1 for As(III) ions in an aqueous solution can reach 74.34nm (5.57 ppb), 451.01mgg-1, and 99.6%, respectively, at pH = 7 and room temperature. With the aid of XPS, IR, Raman, and DFT theoretical calculations, it is determined that CPOSs-NXU-1 adsorbed As(III) ions in the form of H2AsO3 - and H3AsO3 through hydrogen bonding between the host and guest. The mechanism for fluorescence sensitization of As(III) ions to CPOSs-NXU-1 is mainly to increase the energy level difference between the ground state and excited state investigated by UV-vis absorption spectra, UV-vis diffuse reflectance spectra, and theoretical calculations. By constructing fluorescent CPOSs, an integrated solution has been achieved to treating As(III) contamination in the water that is equipped with detection and removal. These results blaze a promising path for addressing trivalent arsenic contamination in water efficiently, rapidly, and economically.