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- 摘要
- 关键词
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过滤筛选
- 2018
- electropolymerization
- polyporphyrin films
- quartz crystal microbalance method
- oxygen electroreduction.
- Applied Chemistry
- G.A. Krestov Institute of Solution Chemistry of RAS
- University Union Nicola Tesla
- Ivanovo State University of Chemistry and Technology
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Synthesis, Structural, Electrochemical and Energy Transfer Studies of π‐Extended Mono‐β‐Functionalized Porphyrin Dyads
摘要： A series of π-conjugated mono-β-functionalized donor-acceptor porphyrin dyads (1-4) with various (phenyl, naphthyl, anthracenyl and pyrenyl) donors and their metal complexes (M = Zn(1a-4a), Cu(1b-4b), Co(1c-4c) and Ni(1d-4d)) were synthesized and characterized by various spectroscopic and electrochemical techniques. Modified one-step Horner-Wadsworth-Emmons reaction was performed on monoformyl porphyrin to get ethenyl linked mono-β-porphyrin dyads in good to excellent yields (70-90%). Red shifted absorption and emission spectra were observed as compared to unsubstituted pristine tetraphenylporphyrins due to π-extended donors. Time resolved fluorescence studies confirmed the effective intramolecular F?rster energy transfer from donor moiety to porphyrin core in anthracene and pyrene appended porphyrin dyads. DFT and TD-DFT optimization signified the orientation of donor and acceptor plays a vital role in energy transfer as co-planarity of donor with porphyrin core increases the energy transfer efficiency. The distribution of electron density on HOMOs and LUMOs indicated the EET mechanism from donor moiety to porphyrin acceptor core. All porphyrin dyads exhibited cathodic shift in their oxidation potential suggesting facile oxidation of porphyrin core due to π-extension and the presence of electron donating moieties. Finally, femtosecond transient absorption spectral studies were performed to secure evidence of excitation transfer and kinetic information of the energy transfer event in the dyads.
关键词： DFT,energy transfer,mono-β-functionalized,porphyrin dyads,Horner-Wadsworth-Emmons reaction,π-Extended,femtosecond transient absorption,TD-DFT
更新于2025-09-04 15:30:14
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Applicability of the thin-film approximation in terahertz photoconductivity measurements
摘要： Thin mesoporous photoconductive layers are critically important for efficient water-spitting solar cells. A detailed understanding of photoconductivity in these materials can be achieved via terahertz transient absorption measurements. Such measurements are commonly interpreted using the thin-film approximation. We compare this approximation with a numerical solution of the transfer function without approximations using experimental results for thin-film mesoporous tin oxide (SnO2) samples which range in thickness from 3.3 to 12.6 mm. These samples were sensitized with either a ruthenium polypyridyl complex or a porphyrin dye. The two sensitizers have markedly different absorption coefficients, resulting in penetration depths of 15 mm and 1 mm, respectively. The thin-film approximation results are in good agreement with the numerical work-up for the short penetration length dye. For the longer penetration length samples, the thin-film formula fails even for thicknesses of only 3 mm (cid:2) k/100. The imaginary part of the conductivity calculated using the thin-film formula was significantly larger in magnitude than the value without approximations. This discrepancy between the commonly used thin-film approximation and the numerical solution demonstrates the need for a careful analysis of the thin-film formula.
关键词： thin-film approximation,terahertz photoconductivity,mesoporous SnO2,ruthenium polypyridyl complex,porphyrin dye
更新于2025-09-04 15:30:14
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Folic acid-nanoscale gadolinium-porphyrin metal-organic frameworks: fluorescence and magnetic resonance dual-modality imaging and photodynamic therapy in hepatocellular carcinoma
摘要： Background: Hepatocellular carcinoma (HCC) is the most common primary liver cancer and severely threatens human health. Since the prognosis of advanced HCC remains poor, there is an urgent need to develop new therapeutic approaches. Porphyrin metal-organic frameworks are a class of porous organic-inorganic hybrid functional materials with good biocompatibility. Methods: Gadolinium-porphyrin metal-organic frameworks were used as a skeleton for folic acid (FA) conjugation to synthesize a novel type of nanoparticle, denoted as folic acid-nanoscale gadolinium-porphyrin metal-organic frameworks (FA-NPMOFs). The FA-NPMOFs were characterized using transmission electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric-differential thermal analysis. The biotoxicity and imaging capability of the FA-NPMOFs were determined using HepG2 cells and embryonic and larval zebrafish. The delivery and photodynamic therapeutic effect of FA-NPMOFs were explored in transgenic zebrafish with doxycycline-induced HCC. Results: FA-NPMOFs were spherical in structure with good dispersion and water solubility. They showed low biotoxicity, emitted bright red fluorescence, and exhibited an excellent magnetic resonance imaging capability, both in vitro and in vivo. Meanwhile, the FA-NPMOFs exhibited a strong affinity for folate receptor (FR)-expressing cells and were delivered to the tumor site in a targeted manner. Moreover, HCC tumor cells were eliminated following laser irradiation. Conclusion: FA-NPMOFs can be used for dual-modality imaging and photodynamic therapy in HCC and show promise for use as a carrier in new therapies for HCC and other FR-positive tumors.
关键词： nanoscale gadolinium-porphyrin metal-organic frameworks,folic acid,hepatocellular carcinoma,photodynamic therapy,dual-modality imaging
更新于2025-09-04 15:30:14
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Chiroptical Protocol for the Absolute Configurational Assignment of Alkyl-Substituted Epoxides Using Bis(zinc porphyrin) as a CD-Sensitive Bidentate Host
摘要： The absolute configurations of simple alkyl-substituted chiral epoxides not bearing other ligating groups are readily determined via the exciton-coupled circular dichroism (ECCD) protocol using a bidentate bis(zinc porphyrin) host system BP1 as a CD-sensitive chirality probe. In this situation, chiral epoxides can successfully be incorporated into the cleft of the V-shaped host BP1 by double coordination of both oxygen lone pairs of the guest to the two central zinc ions of the host. We also propose a working model based on an MM2 optimized structure of the substrates that enables nonempirical prediction of the chirality of the bound epoxide.
关键词： chirality probe,alkyl-substituted epoxides,bis(zinc porphyrin),absolute configurations,exciton-coupled circular dichroism
更新于2025-09-04 15:30:14