Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy最新文献

Methylene blue (MB), as a phenothiazine dye, causes a harmful damage to health and receives increasingly more environmental concern. Herein, the batch experiments for MB biosorption and biotransformation by Haematococcus pluvialis were carried out to evaluate the optimal parameters of MB removal. In this work, we found that the maximum removal efficiency was attained when MB was at the initial concentration of 5 mg/L. Meanwhile, the cellular numbers and pigments decreased dramatically with the rising content of MB. Furthermore, synchrotron-FTIR microscopic imaging is employed here to investigate the interaction between MB dye and algal cells by the measurement of the various vital changes of cellular components involving in the bioremediation of the hazardous dye, which indicated that MB dye as a photosensitizer can trigger the algal transformation from vegetative cells into red cysts by introducing oxidative stress. Accordingly, the dye removal efficiency can be sharply enhanced by the transformed algal cells for the accumulation of astaxanthin or carotenoids. In addition, the FTIR spectroscopy combined with PCA algorithm was further utilized to discriminate various algal status based on their spectral features. As a result, it demonstrates that microscopic imaging and FTIR spectroscopy is a powerful and useful tool to elucidate underlying mechanisms of dye removal by algal cells at high spatial resolution and to evaluate cellular physiological characteristics through multivariate statistical analysis, and it even provides a novel and effective strategy to rapidly screen the potential microalgae for the removal of recalcitrant dyes from wastewater.

Phosphate pollution leads to the deterioration of water quality, posing a serious threat to human health. Tetracycline hydrochloride (TC), a class of broad-spectrum bacteriostatic agents, has garnered attention due to its extensive use and potential toxicity. Therefore, developing a highly selective and sensitive fluorescent probe for the detection of phosphates and TC is of significant importance. Herein, to enhance the conversion and utilization of high-value biomass waste, biomass-derived carbon dots (LZ-NCDs) emitting green fluorescence with a quantum yield of 44 % were synthesized in a one-step hydrothermal process using chestnut shell biomass waste as a carbon source and nitrogen doping technology. Based on the dynamic quenching mechanism, a highly sensitive method for effectively identifying PO₄^3- using LZ-NCDs fluorescence probe was constructed, with a linear range of 0.1-10 µmol/L and a detection limit of 43.0 nmol/L. A quenched fluorescent probe, LZ-NCDs for the determination of TC, was fabricated through the synergistic effects of inner filter effect and static quenching, exhibiting a linear range from 0.05 to 10 µmol/L with a detection limit of 16.8 nmol/L. The successful determination of PO₄^3- and TC in actual samples was achieved. The two different quenching mechanisms indicate that LZ-NCDs are expected to become potential sensing materials for the real-time monitoring of PO₄^3- and TC in organisms and food, which is very important for our health.

The research aimed to develop of a thiabendazole-derived dual metal sensing probe (TBZT) for the selective detection of metal ions and to explore its metal complexes in reducing environmental pollutants like nitro-phenol and dyes. Absorption and emission based studies predicted the selectivity and sensitivity of TBZT towards Ni(II) and Co(II) ions which was further validated by ¹HNMR, Mass, FT-IR, DFT, Docking, electrochemical, TGA studies and vibrating sample magnetometer analysis techniques. Limit of detection (LOD) values were calculated as 2 × 10^-10 M and 4.17 × 10^-8 M for Ni(II) metal ion in emission and absorption based techniques respectively and 2.8 × 10^-9 M and 4.5 × 10^-6 M for Co(II). EDTA based Reversible binding behaviour suggested its potential for constructing molecular logic gates. Catalytic studies of metal complexes of TBZT with these metals demonstrated TBZT-Co(II) superior activity in reducing nitro-phenol, rhodamine B and methyl red. Real sample analysis validated its capability for the environmental monitoring of these metal ions. This emphasized its potential application in metal ion detection and catalysis.

The analysis of Raman and Infrared (IR) phonons in monolayered tetragonal (Sr, Ba)₂HfO₄ compounds, which exhibit D₁₇^4h symmetry and belong to the I4/mmm phase of space group 139 with Z = 2, has been conducted using normal coordinates. The Sr₂HfO₄ and Ba₂HfO₄ compounds are the first members of the Ruddlesden-Popper (RP) series denoted as (Sr, Ba)_n+1HfO_3n+1 with n = 1. Nine Short-Range Force Constants (SRFC) have been included in theoretical calculations to analyze the optical phonons of Sr₂HfO₄ and Ba₂HfO₄ compounds within the I4/mmm phase. The assignments of optical vibrational modes in (Sr, Ba)₂HfO₄ compounds have been determined using Wilson's GF-Matrix Method and cross-referenced with data obtained from compounds sharing similar structural characteristics. The analysis also involved studying how the exchange of cation-A (A = Sr, Ba) impacts the lattice dynamics of the isostructural compounds A₂HfO₄ (A = Sr, Ba) in monolayered tetragonal structures. In this analysis, a comparison has been made between the vibrational modes at the Zone Center, the force constants, and bond lengths to assess the influence of the cation exchange. Furthermore, for each normal mode in the Ruddlesden-Popper phase (Sr, Ba)₂HfO₄, the examination of Potential Energy Distribution (PED) sheds light on the significant impact exerted by Short-Range Force Constants on the calculated vibrational modes, providing a deeper understanding of their behavior and interactions.

The adverse effects of Al³⁺ ions on human health necessitate the development of ultra-sensitive detection methods for Al³⁺ ions. In this regard, the compact and portable design of the detection substrate is of utmost importance for achieving in-situ and sensitive detection of Al³⁺ ions. In our study, we have successfully developed a surface-enhanced Raman scattering (SERS) platform with gold nanoparticles (Au NPs) that was modified with histidine (His) and 4-mercaptobenzoic acid (4-MBA) for the SERS detection of Al³⁺ ions. His and 4-MBA molecules are attached to the Au NPs through a co-assembly strategy. His with amino and carboxyl groups imparts the Au NPs with an aggregation effect against Al³⁺ ions, while 4-MBA provides the SERS responsiveness. The coordination effect of Al³⁺ ions leads to the aggregation of Au NPs, creating hot spots around the 4-MBA molecules and thereby enhancing the SERS signals. Based on this principle, we have constructed a SERS analysis method for detecting Al³⁺ ions in solution. Furthermore, the paper-based plasmonic strips loaded with His-4-MBA-Au NPs have been successfully employed for the SERS detection of Al³⁺ ions. These strips exhibit a significantly higher enhancement factor of 9.77 × 10⁶ compared to the solution system, thanks to the physical aggregation of the strips. The Au NPs tend to generate localized electromagnetic hot spots on the surface of strips, playing a critical role in achieving superior SERS performance. The limit of detection (LOD) of His-4-MBA-Au NPs for Al³⁺ detection is as low as 7.38 nM. The fabricated strips have also undergone repeatability testing and analysis of real samples. The established platform for the detection of Al³⁺ ions holds great promise for portable and on-the-spot analysis.

Organic room-temperature phosphorescence (RTP) luminogens have showed significant potential in the fields of diagnostics, sensing, and information encryption. However, it is difficult to achieve high RTP yield (Φ_P) and long RTP lifetime simultaneously. By methyl substitution, positional isomerism, and host-guest doping, three new D-π-A type luminogens named as TBTDA, 2M-TBTDA, and 3M-TBTDA were designed and synthesized, whose RTP properties were tuned and optimized. In various solvents and glassy THF solution, similar solvatochromism and phosphorescence nature of three luminogens were revealed. In poly (methyl methacrylate) (PMMA) and polyvinyl alcohol (PVA) matrixes, the luminogens showed high-contrast RTP properties. TBTDA emitted invisible afterglow in PMMA films, but with strong RTP and long green afterglow in PVA films. More importantly, 2M-TBTDA showed RTP and afterglow lifetimes of 809.81 ms and 8 s, as well as Φ_P of up to 0.64 in PMMA at 1 % doping concentration. Taking advantage of Foerster resonant energy transfer (FRET), reddish-brown or orange afterglow were observed, with emission maxima of 593-617 nm, RTP and afterglow lifetimes of 299-566 ms and 5-6 s, Φ_P of 0.34-0.46, as well as FRET efficiency of 70-90 %. Finally, dynamic anti-counterfeiting and digital encryption were successfully constructed via different fluorescence, RTP colors, and afterglow lifetimes. This work not only obtained an efficient host-guest doping RTP system, but also can be expected to provide more theoretical guidance and experimental supports for molecular design, dynamic anti-counterfeiting and digital encryption.

A zinc(II) coordination polymer, [Zn(H₂dhtp)(2,2'-bpy)(H₂O)]_n (1), has been utilized as a dual-mode luminescence-colorimetric sensor (H₂dhtp^2- = 2,5-dihydroxy terephthalate and 2,2'-bpy = 2,2'-bipyridine). The presence of hydroxyl groups in H₂dhtp^2- can promote excited-state intra- and intermolecular proton transfer (ESIPT) phenomena. Therefore, compound 1, which displays high stability in aqueous environments, exhibits a strong green-yellow photoluminescence. This luminescence signal can be considerably enhanced and blue-shifted upon the addition of Al³⁺ ions with a limit of detection (LOD) of 0.15 μM, and it demonstrates significant resistance to interference from several competing metal ions. To demonstrate a practical application, 1@paper strips were fabricated that can visually detect the Al³⁺ ion under a UV lamp. Moreover, 1 can detect either Fe²⁺ or Fe³⁺ ions in aqueous solutions by a visible color shift. Upon the incremental addition of Fe²⁺ or Fe³⁺ ions, the solution color changed from colorless to pink, exhibiting a pronounced absorption band at around 521 nm. The LODs were determined to be 1.55 and 0.34 μM for Fe²⁺ and Fe³⁺, respectively. Furthermore, compound 1 was used for the determination of Fe³⁺ ions in the real water samples, which can be evaluated on-site in real-time via a smartphone color-scanning application. The detection efficacy of 1 toward Al³⁺ and Fe²⁺/Fe³⁺ maintains significant luminescence stability and reusability.

Organic photovoltaics (OPVs) have improved greatly in recent years in pursuit for efficient and sustainable energy conversion methods. Specifically, utilizing quantum chemistry approaches such as density functional theory (DFT), the electronic structures, energy levels, and charge transport characteristics of donor-π-acceptor (D-π-A) systems based on non-fullerene donor and acceptor molecules have been examined and synthesized. Non-fullerene acceptors offer several advantages over traditional fullerene-based materials, such as enhanced light absorption, modifiable energy levels, and reduced recombination losses. Quantum mechanical simulations are helpful in the design and development of these materials because they can accurately predict the energy level alignment, molecule interactions, and charge transport properties needed for the high-efficiency of OPVs. The research begins through the selection of electron-donating and electron-accepting non-fullerene polymeric molecules using the unique properties of non-fullerene derivatives and non-fullerene acceptors. The theory uses the B3LYP-D3 method with a 6-31+G (d,p) basis set. PY-IT is used as the reference molecule, and eight molecules PY-IT01-PY-IT08, has been created by changing the end caps of the acceptor units. The created compound has superior photovoltaic characteristics. Focus has been specifically given to the frontier molecular orbitals (FMOs), natural bond order (NBO) analysis, reorganization energies (RE), and absorption spectra in order to assess the viability of charge separation and efficient light absorption. Finally, the molecular electrostatic potential (MEP) analysis, transition density matrix (TDM) analysis, and improved open circuit voltage (Voc) all have been computed. The results of the findings provide new insight to design organic solar cells (OSCs) with improved photovoltaic and solar energy conversion capabilities, which has great potential for the future development of more dependable and efficient OSCs.

Herein, nitrogen doped carbon quantum dots (N-CQDs) were synthesized using a hydrothermal strategy. The raw materials for the preparation of N-CQDs were sourced from pumpkin and melamine. The N-CQDs suggested fascinating water solubility, favorable UV and salt resistance stability. The fluorescence quantum yield of N-CQDs was carried out to be 16.7 %. The prepared N-CQDs suggested good optical features and favorable blue fluorescence under a UV lamp (365 nm). The as-prepared N-CQDs could be employed as rapid, sensitive and promising fluorescence nanoprobes to detect nifuratel because of static quenching and inter filter effect. For nifuratel detection, the linear range of 0.5-100 μM and detection limit of 0.074 μM were obtained. Furthermore, N-CQDs were subsequently applied to determine nifuratel in river water and Yili milk samples with acceptable experiment results. Significantly, N-CQDs suggested evident temperature-sensitive characteristics and were employed as fluorescent temperature sensing nanoprobes.

Alkenyl pheromones are a class of insect sex pheromones that are characterized by the presence of one or more double bonds, which can be either in the E(trans) or Z(cis) configuration. This structural variation is essential in mating, as it influences reproductive behavior and provides a potential method for insect control. As a base for rapid and in-situ screening of synthetic pheromones or pheromone-based products, this study explores the potential of Raman spectroscopy to differentiate between the two geometrical isomers, E(trans) and Z(cis), of the alkenyl pheromones. As a case study, four types of pheromones were analyzed: 5-decen-1-ol, 8-dodecyl acetate, 9-dodecyl acetate, and 10-dodecyl acetate; in the latter case, the E(trans) isomer was particularly investigated. In this regard, a detailed analysis of their experimental Raman spectra has been realized along with a DFT-based study of the investigated compounds. Moreover, to find the best machine learning (ML) model that can efficiently identify the E(trans) or Z(cis) isomers of alkenyl pheromones, several algorithms and two different designs of datasets were tested. The results indicate that the ML models could identify patterns and accurately predict the class even if the training dataset contains both experimental and theoretical data.