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Excitation energy transfer in the far-red absorbing violaxanthin/vaucheriaxanthin chlorophyll a complex from the eustigmatophyte alga FP5
摘要： This work highlights spectroscopic investigations on a new representative of photosynthetic antenna complexes in the LHC family, a putative violaxanthin/vaucheriaxanthin chlorophyll a (VCP) antenna complex from a freshwater Eustigmatophyte alga FP5. A representative VCP-like complex, named as VCP-B3 was studied with both static and time-resolved spectroscopies with the aim of obtaining a deeper understanding of excitation energy migration within the pigment array of the complex. Compared to other VCP representatives, the absorption spectrum of the VCP-B3 is strongly altered in the range of the chlorophyll a Qy band, and is substantially red-shifted with the longest wavelength absorption band at 707 nm at 77 K. VCP-B3 shows a moderate xanthophyll-to-chlorophyll a efficiency of excitation energy transfer in the 50–60% range, 20–30% lower from comparable VCP complexes from other organisms. Transient absorption studies accompanied by detailed data fitting and simulations support the idea that the xanthophylls that occupy the central part of the complex, complementary to luteins in the LHCII, are violaxanthins. Target analysis suggests that the primary route of xanthophyll-to-chlorophyll a energy transfer occurs via the xanthophyll S1 state.
关键词： Chlorophyll a,Light-harvesting complex,Transient absorption,Violaxanthin,Photosynthesis,Vaucheriaxanthin
更新于2025-11-19 16:46:39
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Luminescent rhenium(I) carbonyl complex with redox noninnocent ONS donor azo-phenol ligand: Synthesis, X-ray structure, photophysical properties and live cell imaging
摘要： Herein, we have synthesized a new fluorescent rhenium(I) carbonyl complex 1, bearing {Re(CO)3}+ core with ONS donor thioether containing azo-phenol redox noninnocent ligand. The distorted octahedral geometry of the complex is confirmed by single crystal X-ray diffraction method. Cyclic voltammogram in acetonitrile exhibits irreversible oxidation peak (Epa = 1.36 V) along with quasi-reversible reduction peak at E1/2 = -0.92 V (ΔE = 210 mV). The complex exhibits low energy emission band at 525 nm with high emission quantum yield (Φ = 0.115). Cytotoxicity of the complex is studied by MTT method with human breast cancer cell lines (MCF-7) and IC50 value is found to be 23.6 μM. In presence of the complex (10 μM) a bright green fluorescence image of MCF-7 cell lines is observed under fluorescence microscope.
关键词： Electrochemistry,ONS donor ligand,MTT assay,Rhenium(I) carbonyl complex,Live cell imaging
更新于2025-11-19 16:46:39
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Aggregation-induced phosphorescence quenching method for the detection of picric acid based on melamine-passivated Mn-doped ZnS quantum dots
摘要： Melamine (MA)-passivated Mn-doped ZnS quantum dots (QDs) were synthesized by a hydrothermal method. The MA-passivated QDs can form a charge-transfer complex with picric acid (PA) at 80 °C, thereby quenching the phosphorescence of the QDs. A sensitive method for detecting PA was established based on this principle of phosphorescence quenching. When the PA concentration ranged from 2.0–180 ng mL–1, the concentration was linearly related to the quenching intensity of the QDs, with a detection limit of 1.4 ng mL–1. When applied to detect PA in environmental water samples, the proposed method showed superior analytical performance compared with other PA analysis methods. Furthermore, we verified the static quenching mechanism by density functional theory. MA on the surface of QDs and PA formed a stable structure with a binding energy of 12.43 eV.
关键词： Melamine,Picric Acid,Mn-doped quantum dots,Charge-transfer Complex,Phosphorescence
更新于2025-11-14 17:04:02
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Ammonia-Responsive Luminescence of Ln3+-β-diketonate Complex Encapsulated within Zeolite Y
摘要： Assembling Ln3+(HPBAn) (Ln = Eu or Tb, HPBA = N-(2-pyridinyl)benzoylacetamide) in the cavities of zeolite Y (ZY) via the “ship-in-a-bottle” strategy leads to the formation of novel luminescent composite, Ln(HPBAn)@ZY, whose luminescence can be easily modulated by ammonia on the basis of the energy level variation of HPBA after deprotonation process. Additionally the bimetallic complex doping sample, Eu0.5Tb0.5(HPBAn)@ZY, show great potential as self-referencing luminescent sensor for detecting low ammonia concentration of 10?12–0.25 wt%.
关键词： zeolite Y,luminescence,Ln3+-β-diketonate complex,ammonia-responsive
更新于2025-11-14 15:18:02
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Study of visible-light photocatalytic degradation of 2,4-dichlorophenoxy acetic acid in batch and circulated-mode photoreactors
摘要： Purpose The consumption of pesticides and chemical fertilizers is one of the major environmental and health problems. In this report, 2,4-dichlorophenoxyacetic acid (2,4-D) was chosen to evaluate the impact of photodegradation using LED (Light-emitting diode) (400 and 365 nm) sources in batch and programmable circulated-mode photoreactors respectively. Methods A β-cyclodextrin (β-CD) grafted titanium dioxide P25 (P25/β-CD) and complexation of 2,4-D and β-CD were synthesized via photoinduced and spray-drying methods, respectively. The structures were characterized. Moreover, we investigated the effects of the amount of catalyst, the β-CD amount on bed catalyst, irradiation time, kind of photoreactor on the photocatalytic degradation efficiency. Results Based on the results of experiments in batch reactor, the optimum amount of TiO2, β-CD grafted by catalyst were 1 and 0.1 g/L, respectively. In batch-mode the photodegradation efficiency of 2,4-D after 5 h with P25, P25/β-CD as a photocatalyst and 2,4-D/β-CD complex with P25 photocatalyst were approximately 81, 85 and 95% respectively. After 8 h of irradiation in circulated-mode reactor, degradation yields with P25, P25/β-CD and 2,4-D/β-CD complex along with P25 were 89, 91 and 96% respectively. On the other hand, the circulated-mode photoreactor with high efficiency was appropriate to degradation of the high concentration of 2,4-D solution (200 mg/L). After 5 successive cycles with 25 h of irradiation, P25 and P25/β-CD maintained as high 2,4-D removal efficiency as 82.6, 84% respectively, with excellent stability and reusability. Conclusion The photodegradation method can be used as an effective and environmental friendly process in the degradation of organic compound.
关键词： 2,4-D/β-CD complex,Batch-mode photoreactor,Light-emitting diode (LED),Circulated-mode photoreactor,2,4-Dichlorophenoxyacetic acid (2,4-D)
更新于2025-11-14 15:18:02
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First titanium square fragment {Ti4(μ4-Se)(μ2-Se2)4} in its selenoiodide: Synthesis and structure of Ti4Se9I6
摘要： The first titanium selenoiodide Ti4Se9I6 was synthesized as black crystals by heating of Ti, Se, and I2 at 250 °C in 5:9:5 M ratio. The crystal structure of the compound was solved by X-ray single-crystal diffractometry (sp. gr. P-1, a = 7.9652(10), b = 10.3390(15), c = 15.692(2) ?; α = 79.116(7)°, β = 75.861(7)°, γ = 71.437(7)°; Z = 2) with final R1 = 0.0397. The structure includes square {Ti4(μ4-Se)(μ2-Se2)4} fragment coordinated by four terminal and four bridging μ2-I atoms. Ti4+ has d0 configuration, and stability of the structure fragments is provided by metal to ligand bonding which was confirmed by DFT calculations.
关键词： Metal chalcohalides,Titanium,Square complex,Synthesis,Selenide,X-ray crystal structure,Chain structure,DFT calculations,Iodide
更新于2025-11-14 15:14:40
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Synthesis, Crystal Structure and Fluorescent Properties of 1D New Double Chain Silver(I) Complex
摘要： A novel silver(I) complex [Ag(btzx)2(NO3)]n [complex 1, where btzx = m-xylylenebis(tetrazole)] is synthesized and characterized by elemental analysis, IR, powder and single crystal X-ray diffraction. The crystal structural analysis shows that silver center is four-coordinated in a distorted tetrahedral geometry by four nitrogen atoms from four different btzx and there are very weak interactions exist between Ag(I) and NO3– anions. This complex displays a 1D ladder-like double chain framework, which is further fabricated into a 2D supramolecular framework via π–π interactions. The fluorescence properties of complex 1 were investigated.
关键词： Silver complex,Coordination polymers,Flexible ligand,m-Xylylenebis(tetrazole)
更新于2025-11-14 14:48:53
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Complex Inverse Design of Meta-optics by Segmented Hierarchical Evolutionary Algorithm
摘要： With the recent burgeoning advances in nano-optics, ultracompact, miniaturized photonic devices with high-quality and spectacular functionalities are highly desired. Such devices’ design paradigms often call for the solution of a complex inverse nonanalytical/semianalytical problem. However, currently reported strategies dealing with amplitude-controlled meta-optics devices achieved limited functionalities mainly due to restricted search space and demanding computational schemes. Here, we established a segmented hierarchical evolutionary algorithm, aiming to solve large-pixelated, complex inverse meta-optics design and fully demonstrate the targeted performance. This paradigm allows significantly extended search space at a rapid converging speed. As typical complex proof-of-concept examples, large-pixelated meta-holograms are chosen to demonstrate the validity of our design paradigm. An improved fitness function is proposed to reinforce the performance balance among image pixels, so that the image quality is improved and computing speed is further accelerated. Broadband and full-color meta-holograms with high image fidelities using binary amplitude control are demonstrated experimentally. Our work may find important applications in the advanced design of future nanoscale high-quality optical devices.
关键词： full-color meta-holograms,fast-converging algorithm,meta-optics,segmented hierarchical evolutionary algorithm,complex large-pixelated inverse design
更新于2025-09-23 15:23:52
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Linear complex susceptibility of long-range interacting dipoles with thermal agitation and weak external ac fields
摘要： An analytical formula for the linear complex susceptibility of dipolar assemblies subjected to thermal agitation, long-range interactions, and an externally applied uniform sinusoidal field of weak amplitude is derived using the forced rotational diffusion equation of Cugliandolo et al. [Phys. Rev. E 91, 032139 (2015)] in the virial approximation. If the Kirkwood correlation factor of the dipolar assembly gK exceeds unity, a thermally activated process arising from the interaction-specific component arises, while for gK < 1 the susceptibility spectrum normalized by its static value is practically unaltered with respect to that of the ideal gas phase.
关键词： long-range interactions,thermally activated process,dipolar assemblies,thermal agitation,Kirkwood correlation factor,linear complex susceptibility
更新于2025-09-23 15:23:52
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Crystal Structure and Luminescence of a Novel Binuclear Zinc(II) Complex with Di-2-Pyridylamine And 4,4′-Sulfonyldibenzoate
摘要： A binuclear Zn(II) complex [Zn2(SDBA)2(DPA)2?2H2O] (1) (DPA = di-2-pyridylamine, H2SDBA = 4,4′-sulfonyldibenzoic acid) is synthesized and characterized using single crystal X-ray diffraction, IR spectroscopy, and elemental analysis. The single crystal X-ray diffraction analysis reveals that complex 1 is a binuclear zinc(II) complex. The binuclear molecules are further connected by three types of N–H?O, C–H?O, and O–H?O hydrogen bonds, generating a three-dimensional supramolecular structure. Meanwhile, S–O?π interactions further consolidate the three-dimensional supramolecular framework of 1. In addition, the thermal stability and luminescent properties of the title complex are briefly investigated. The luminescence measurements reveal that complex 1 exhibits fluorescent emission in the solid state at room temperature.
关键词： luminescence,4′-sulfonyldibenzoic acid,crystal structure,4,Zn(II) complex,di-2-pyridylamine
更新于2025-09-23 15:23:52