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Influence of the supramolecular arrangement of iron phthalocyanine thin films on catecholamine oxidation
摘要： The versatility of iron phthalocyanine (FePc) to form distinct supramolecular arrangements in thin films, characterized by their thickness, molecular organization, morphology, and crystallinity, can be used to tune the electrochemical oxidation of catecholamines, becoming a promising material for sensing applications. Here, Langmuir-Schaefer (LS) and electrodeposition (ED) techniques have been used to produce thin films of FePc with different supramolecular arrangements on ITO electrodes. Both types of modified electrode were evaluated for the electrochemical oxidation of L-Dopa, dopamine (DA), norepinephrine (NEp), and epinephrine (Ep) in aqueous solution. The effect of scan rate, potential range, presence of oxygen, and pH were also evaluated, having an influence on the electrochemical oxidation of catecholamines. The FePc/ED modified electrodes showed two distinct peaks in the presence of mixtures of DA/L-Dopa and DA/Ep, while for FePc/LS modified electrodes an overlap of the oxidation waves was observed. This behaviour reveals the influence of the supramolecular arrangement of FePc on catecholamine oxidation. The FePc/LS modified electrodes showed a limit of detection of 0.024 μmol L-1 for DA and 0.168 μmol L-1 for L-Dopa, while FePc/ED showed limits of detection of 0.288 μmol L-1 and 0.564 μmol L-1, respectively. The FePc films showed suitable properties for future application as catecholamine sensors.
关键词： electrodeposition,Langmuir-Schaefer,iron phthalocyanine,catecholamines
更新于2025-09-23 15:23:52
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Synthesis of tetra-substituted phthalocyanines bearing 2-(ethyl(m-tolyl)amino)ethanol: Computational and photophysicochemical studies
摘要： This work presents the synthesis of 4-(2-(ethyl(m-tolyl) amino) ethoxy) phthalonitrile (1) as ligand and its peripherally tetrasubstituted metal-free (2) and metallophthalocyanines (3-5) derivatives. Synthesized compounds were characterized by standart spectroscopy methods. The molecular structure of the ligand (1) was confirmed by single-crystal X-ray diffraction experiment. The crystallographic information file (cif) was uploaded to the data center with CCDC number 1853485. The optimized structure of the ligand (1) and the phthalocyanines (2-5) were obtained by using different metods such as B3lyp, HF and m062x method 3-21g, 6-31g, sdd basis set. In b3lyp/6-31++g(d,p) basis set, 1H and 13C NMR chemical shifts, IR spectrum and UV-Vis spectrum were measured in gas, chloroform and dimethylsulfoxide phase by means of the obtained optimized structure. Besides, the photophysical and photochemical properties of newly synthesized phthalocyanines (2-5) were investigated in DMSO, comparatively. Singlet oxygen quantum yields of the phthalocyanines (2-5) are ranging from 0.28 to 0.70.
关键词： synthesis,Phthalocyanine,photochemistry.,crystal structure,computational studies
更新于2025-09-23 15:23:52
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Mechanism of field-induced manipulation of Cu-phthalocyanines on a Bi surface using scanning tunneling microscope
摘要： We have revisited our hypothesis [K. Nagaoka et al., Jpn. J. Appl. Phys. 57 (2018) 020301] regarding the control of the motion and assembly of copper phthalocyanine (CuPc) molecules on a Bi(001) surface using a scanning tunneling microscope (STM) tip. The proposal that the observed diffusion and condensation are not due to the adsorption/desorption of molecules via the tip by applying a bias voltage was investigated for field-induced manipulation. Our experiments show that CuPc cannot move across steps or condense on different terraces on the Bi(001) surface. When confined to a nano-scale region, the CuPc molecules assemble into ordered single-layer islands. The island position can be manipulated using the STM tip, with an almost constant number of condensed molecules remaining inside the terrace. These results allowed us to rule out the possibility of picking-up and depositing molecules by the STM tip.
关键词： STM,phthalocyanine,self-assembly,field-induced manipulation,bismuth,surface science
更新于2025-09-23 15:23:52
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Resistive Switching and Nonvolatile Memory in TiO2/CuPc Nanocomposite Devices
摘要： An organic–inorganic nanocomposite has been prepared as a hybrid memory element, and a bistable data storage device has been fabricated. The composite device, consisting of a spin casted thin film of sol–gel derived titanium dioxide (TiO2) nanoparticles followed by a vacuum evaporated thin film of copper phthalocyanine (CuPc), exhibits conductance switching and nonvolatile memory phenomenon. While the single layer device with TiO2 nanoparticles showed unipolar switching characteristics, the composite device exhibited bipolar switching with highly improved performance. The erase/reset voltage for the single layer TiO2 device is 4.5 V, which reduces to |3| V for the composite device. The on/off current ratio of the composite device measured to be > 104 , which is orders of magnitude higher in comparison to that in the single layer devices. The charge transport mechanism of the devices revealed that trap-related space charge limited conduction mechanism might be responsible for the composite device while it indicates possible formation of filamentary path in the single layer TiO2 based devices leading to ohmic-like conduction. The ability of the composite device to write, erase, read, and refresh the electrical states fulfills the functionality of a dynamic random access memory having potential for next generation low cost memory applications.
关键词： Memory,bistability,phthalocyanine,nanocomposite,random access memory
更新于2025-09-23 15:22:29
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Sequential Photodynamic Therapy with Phthalocyanine Encapsulated Chitosan-Tripolyphosphate Nanoparticles and Flucytosine Treatment against Candida tropicalis
摘要： Antibiotic resistance has become a crisis. Candida tropicalis (C. tropicalis) is one of the most highly virulent and drug-resistant pathogens. An alternative antimicrobial therapy to eradicate C. tropicalis effectively, without the risk of developing drug-resistance, is needed. Photodynamic therapy (PDT) is an alternative therapy that does not carry the risk of undesired drug resistance. To target the pathogens and to enhance the cellular penetration of the applied photosensitizer, we fabricated cationic chitosan/tripolyphosphate nanoparticles to encapsulate phthalocyanine. Our strategy promotes the uptake of phthalocyanine four-fold. This enhanced PDT can effectively inhibit planktonic C. tropicalis, such that only ~20% of C. tropicalis in the test survived; but it has a limited ability to inhibit adherent C. tropicalis. Further tests with adherent C. tropicalis indicated that sequential treatment with PDT and flucytosine significantly eliminates pseudohyphae and yeast-like C. tropicalis cells. The cell viability is only ~10% after this sequential treatment. This study provides evidence of an effective therapy against drug resistant C. tropicalis, and this strategy can be potentially applied to other pathogens.
关键词： photodynamic therapy,chitosan,Candida tropicalis,phthalocyanine,flucytosine
更新于2025-09-23 15:22:29
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Encapsulation of zinc phthalocyanine into bovine serum albumin aggregates
摘要： Artificial hybridization of molecules with proteins is beneficial for biomedical applications. Herein, we describe a novel method for encapsulation of zinc phthalocyanine (ZnPc) aggregates into bovine serum albumin (BSA) aggregates, but not monomeric BSA. This property is potentially useful for not only photodynamic or photothermal therapy but also development of a novel delivery system for hydrophobic drug molecules.
关键词： Gel-filtration chromatography,Photosensitizer,Aggregation,Bovine serum albumin,Phthalocyanine,Photodynamic therapy
更新于2025-09-23 15:22:29
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Facile Preparation of Unsubstituted Iron(II) Phthalocyanine/Carbon Nitride Nanocomposites: A Multipurpose Catalyst with Reciprocally Enhanced Photo/Electrocatalytic Activity
摘要： The development of new catalytic materials is conducive to solving the global energy crisis and environmental problems. In this work, multipurpose catalyst unsubstituted iron(II) phthalocyanine/carbon nitride nanosheet (FePc/CN) nanocomposites were prepared by utilizing concentrated sulfuric acid as an ideal solvent of CN and unsubstituted FePc. Such FePc/CN nanocomposites exhibited improved photo/electrocatalytic activity which was enhanced reciprocally: the photocatalytic activity of CN was promoted by FePc anchoring, and the electrocatalytic activity of FePc was improved by CN doping. The photocatalytic performance of FePc/CN?0.3 nanocomposites was about 6.4 and 1.7 times as high as FePc and CN, which was attributed to two reasons: (1) the anchoring FePc on CN extended the visible-light absorption region of CN, (2) the electron transfer from excited FePc to CN hindered charge carriers recombination and thus enhanced the photoinduced carrier separation efficiency. Relative to FePc and CN, the onset potential of FePc/CN?0.3 was positively shifted by 52 and 174 mV, such higher oxygen reduction reaction activity was due to the uniform dispersion of FePc on the supporting material CN without aggregation, which led to improved conductivity and stability of nanocomposites. This approach will contribute to an inexpensive and convenient synthetic strategy of transition-metal-based nanostructures for functional applications in photovoltaic, electrochemical, and catalytic fields.
关键词： Unsubstituted iron(II) phthalocyanine,Oxygen reduction reaction,Multipurpose catalyst,Photocatalytic performance,Carbon nitride nanosheet
更新于2025-09-23 15:22:29
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Spectroscopy for contemporary art: Discovering the effect of synthetic organic pigments on UVB degradation of acrylic binder
摘要： The influence of Synthetic Organic Pigments in the degradation of Acrylem AC 33, a waterborne acrylic binder, after UVB-artificial exposure was furtherly investigated, extending the study to other pigments classes (anthraquinones, phthalocyanines, diketo-pyrrolo-pyrroles) in addition to previously studied azo-pigments. Together with Fourier Transform Infrared, both in Attenuated Reflectance and Transmission mode, and Nuclear Magnetic Resonance spectroscopies, Raman spectroscopy was also used to observe ageing processes that pigments are subjected to. Specific effects, relative to the presence of different pigments, have been observed also in this study; moreover, Raman spectroscopy highlighted photoinduced effects on some pigments, which could result useful in Cultural Heritage diagnostics, especially for street artworks.
关键词： diketo-pyrrolo-pyrrole,photodegradation,phthalocyanine,acrylic,anthraquinone
更新于2025-09-23 15:21:21
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Synthesis and biological evaluation of phthalocyanine-peptide conjugate for EGFR-targeted photodynamic therapy and bioimaging
摘要： To improve the biocompatibility and tumor selectivity, we employed an epidermal growth factor receptor (EGFR) binding peptide (namely GE11, with a sequence of Tyr-His-Trp-Tyr-Gly-Tyr-Thr-Pro-Gln-Asn-Val-Ile) as a tumor directing vector for the delivery of zinc(II) phthalocyanine for targeted photodynamic therapy and bioimaging. The photophysical properties, cellular uptake, in vitro cytotoxicity, and in vivo biodistribution of this phthalocyanine-peptide conjugate (namely Pc-GE11) have been evaluated. Pc-GE11 exhibited higher cellular uptake on EGFR-overexpressing epidermoid carcinoma A431 cells when compared with that on human breast adenocarcinoma MCF7 cells (low EGFR expression). Moreover, pretreatment of A431 cells with GE11 peptide inhibited the cellular uptake of Pc-GE11 significantly and it exhibited exclusive light-activated cytotoxicity toward A431 cells. Furthermore, Pc-GE11 showed much higher tumor accumulation than the non-targeted control compound containing a random peptide sequence (Tyr-Trp-Gly-Pro-Asn-Ile-His-Tyr-Tyr-Thr-Gln-Val) after intravenous administration in A431-tumor bearing mice, indicating the potential application of this GE11 peptide-conjugated photosensitizer for targeted photodynamic therapy and bioimaging.
关键词： EGFR-targeted,tumor selectivity,phthalocyanine-peptide conjugate,photodynamic therapy,bioimaging
更新于2025-09-23 15:21:21
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Selectivity of chemosensor phthalocyanines for Pd2+ ions; synthesis, characterization, quantum chemical calculation, photochemical and photophysical properties
摘要： In this study, ligand (1) was prepared by a nucleophilic displacement reaction of (4-bromophenyl)methanethiol with 4-nitrophthalonitrile according to literature and its novel type peripheral substituted tetra phthalocyanines [CuPc (2), ZnPc (3) and GaPc (4)] were prepared. The phthalocyanines obtained from compund (1) were characterized by FT-IR, 1H-NMR, UV-Vis spectral data, elemental analysis, and MALDI-TOF. The novel phthalocyanines [CuPc (2), ZnPc (3) and GaPc (4)] were highly soluble in common organic solvents such as CHCl3, THF, CH2Cl2, DMSO and DMF. The effect of Pd2+ ions on the fluorescence emission and UV-Vis spectra were performed with addition of increasing amounts of Pd2+ ions. This functional phthalocyanines exhibited H-type aggregation versus Pd2+ ions due to special chemical structures, which can be used as a selective chemosensor for Pd2+ ions. Also, the molecular reactivity of the ligand (1) and related metallo phthalocyanines [CuPc (2), ZnPc (3) and GaPc (4)] were investigated and compared with the analysis of frontier molecular orbitals. In addition, photochemical and photophysical properties of these new phthalocyanines (fluorescence quantum yields, fluorescence behavior, singlet oxygen and photodegradation quantum yields) were studied in DMSO.
关键词： Phthalocyanine,Photochemical,Photophysical,Quantum Chemical Calculation,Metal sensor
更新于2025-09-23 15:21:21