Fe Pc Research Articles

Novel nanohybrid iron (II/III) phthalocyanine-based carbon nanotubes as catalysts for organic pollutant removal: process optimization by chemometric approach.

In the present study, two iron phthalocyanine (FePc)-based nanocatalysts were synthesized and fully characterized. The carbon nanotubes (CNT) functionalized in an easy way with either Fe(II)Pc or Fe(III)Pc exhibit a very good catalytical activity. The activity in real wastewater effluent was comparable with the activity in distilled water. The procedure of modeling and optimizing with the assistance of chemometrics, utilizing design of experiments (DOE) and response surface methodology (RSM), revealed the conditions of optimum for decaying Reactive Yellow 84 on the nanocatalysts FePc_CNT. These optimal conditions included a catalyst dose of 1.70 g/L and an initial concentration (C0) of 20.0 mg/L. Under the indicated optimal conditions, the experimental findings verified that the removal efficiency was equal to Y = 98.92%, representing the highest observed value in this study. Under UVA light, after only 15 min of reaction, over 94% of dye was removed using both catalysts. The reuse experiments show that the activity of both nanohybrid material based on FePc-CNT slightly decreases over four consecutive runs. The quenching experiments show that RY84 was removed through radical pathways (O2•- and •OH) as well as non-radical pathways (1O2 and direct electron transfer).

Synthesis of Bicyclo[1.1.1]pentane Carboxamides and Ketones from [1.1.1]Propellane

AbstractBicyclo[1.1.1]pentane (BCP) carboxamides are prepared from the direct addition of [1.1.1]propellane with semicarbazides in the presence of iron(II) phthalocyanine {Fe(Pc)} and tert‐butyl hydroperoxide (TBHP) in moderate to good yields. BCP ketones are also obtained under similar conditions in moderate yields. This protocol provides a straightforward one‐step access to BCP carboxamides, synthesis of which requires multiple chemical steps in previous reports.

Development of Electrochemical Sensor Using Iron (III) Phthalocyanine/Gold Nanoparticle/Graphene Hybrid Film for Highly Selective Determination of Nicotine in Human Salivary Samples.

Nicotine is the one of the major addictive substances; the overdose of nicotine (NIC) consumption causes increasing heart rate, blood pressure, stroke, lung cancer, and respiratory illnesses. In this study, we have developed a precise and sensitive electrochemical sensor for nicotine detection in saliva samples. It was built on a glassy carbon electrode (GCE) modified with graphene (Gr), iron (III) phthalocyanine-4,4',4″,4'''-tetrasulfonic acid (Fe(III)Pc), and gold nanoparticles (AuNPs/Fe(III)Pc/Gr/GCE). The AuNPs/Fe(III)Pc/Gr nanocomposite was prepared and characterized by using FE-SEM, EDX, and E-mapping techniques to confirm the composite formation as well as the even distribution of elements. Furthermore, the newly prepared AuNPs/Fe(III)Pc/Gr/GCE-nanocomposite-based sensor was used to detect the nicotine in phosphate-buffered solution (0.1 M PBS, pH 7.4). The AuNPs/Fe(III)Pc/Gr/GCE-based sensor offered a linear response against NIC from 0.5 to 27 µM with a limit of detection (LOD) of 17 nM using the amperometry (i-t curve) technique. This electrochemical sensor demonstrated astounding selectivity and sensitivity during NIC detection in the presence of common interfering molecules in 0.1 M PBS. Moreover, the effect of pH on NIC electro-oxidation was studied, which indicated that PBS with pH 7.4 was the best medium for NIC determination. Finally, the AuNPs/Fe(III)Pc/Gr/GCE sensor was used to accurately determine NIC concentration in human saliva samples, and the recovery percentages were also calculated.

Unraveling the Electronic Structure and Dynamics of the Atomically Dispersed Iron Sites in Electrochemical CO2 Reduction.

Single-atom catalysts with a well-defined metal center open unique opportunities for exploring the catalytically active site and reaction mechanism of chemical reactions. However, understanding of the electronic and structural dynamics of single-atom catalytic centers under reaction conditions is still limited due to the challenge of combining operando techniques that are sensitive to such sites and model single-atom systems. Herein, supported by state-of-the-art operando techniques, we provide an in-depth study of the dynamic structural and electronic evolution during the electrochemical CO2 reduction reaction (CO2RR) of a model catalyst comprising iron only as a high-spin (HS) Fe(III)N4 center in its resting state. Operando 57Fe Mössbauer and X-ray absorption spectroscopies clearly evidence the change from a HS Fe(III)N4 to a HS Fe(II)N4 center with decreasing potential, CO2- or Ar-saturation of the electrolyte, leading to different adsorbates and stability of the HS Fe(II)N4 center. With operando Raman spectroscopy and cyclic voltammetry, we identify that the phthalocyanine (Pc) ligand coordinating the iron cation center undergoes a redox process from Fe(II)Pc to Fe(II)Pc-. Altogether, the HS Fe(II)Pc- species is identified as the catalytic intermediate for CO2RR. Furthermore, theoretical calculations reveal that the electroreduction of the Pc ligand modifies the d-band center of the in situ generated HS Fe(II)Pc- species, resulting in an optimal binding strength to CO2 and thus boosting the catalytic performance of CO2RR. This work provides both experimental and theoretical evidence toward the electronic structural and dynamics of reactive sites in single-Fe-atom materials and shall guide the design of novel efficient catalysts for CO2RR.

Electrochemical, spectroelectrochemical, and electrocatalytic properties of novel soluble phthalocyanines containing peripheral thymoxy and chloride units

Novel CoPc, CuPc, Fe(OAc)Pc and Mn(Cl)Pc were synthesized by using original 4-chloro-5-(2-isopropyl-5-methylphenoxy)phthalonitrile in order to investigate their potential redox applications suitable with their chemical and physical characteristics. The molecular structures of new compounds were determined with spectroscopic methods such as elemental analysis, FT-IR, UV–vis, NMR and MALDI TOF MS. Redox behaviours of Fe(OAc)Pc and Mn(Cl)Pc complexes have been probed by using diverse voltammetric techniques such as cyclic (CV) and square wave voltammetry (SWV). In addition, the colour alterations accompanying spectral changes were perused concurrently with electrocolorimetric measurements, and electrocatalytic efficiencies of the all compounds were perused in oxygen reduction reaction.

Novel 2,6-dimethoxyphenoxy alpha substituted phthalocyaninato metal complexes: Electrochemistry, In situ spectroelectrochemistry and oxygen electrocatalysis

Non-peripherally tetra-2,6-dimethoxyphenoxy substituted Co(II) 3, Fe(II) 4, Mn(III) 5, and Ni(II) 6 phthalocyanines were prepared by refluxing the n-pentanol solution of their metal-free analogue H2Pc 2, (obtained by using 3-(2,6-dimethoxyphenoxy)phthalonitrile), metal salts (Co(CH3COO)2.4 H2O, Fe(CH3COO)2, Mn(CH3COO)2.4 H2O or NiCl2) and 1,8-diazabicyclo[5.4.0]undec-7-ene(DBU) as the catalyst under N2 atmosphere for 2 h. The molecular structure of metallophthalocyanines 3–6 were explained by common methods which are elemental analysis, MALDI-TOF mass, FTIR, and UV-Vis spectroscopies. The complexes are well dissolved in various solvents (dichloromethane, tetrahydrofuran, dimethylsulfoxide, dimethylformamide, and toluene. Electrochemical redox, electrocatalytic oxygen reducing and electrocolorimetric properties of the phthalocyanine complexes were also measured by voltammetric and in situ UV-Vis spectroelectrochemical techniques. The phthalocyanine complexes displayed highly reversible sequential one-electron redox processes occurring at metal and/or phthalocyanine ring. The association of these processes with net colour changes pointed out their functionality as electrochromic material. Furthermore, the phthalocyanine complexes 3-5 and especially Fe(II)Pc 4, showed striking electrocatalytic oxygen reducing activity, owing to the metal centres with redox activity, increasing their interplay with the O2 molecule.

One‐pot synthesis of 2‐imino‐1,3,4‐thiadiazolines from acylhydrazides and isothiocyanates

AbstractA one‐pot synthesis of 2‐imino‐1,3,4‐thiadiazolines was successfully achieved under mild conditions. The developed synthesis involves Fe(Pc)‐catalyzed aerobic oxidation of acylhydrazides followed by P(NMe2)3‐mediated annulation of the in situ generated N‐acyldiazene with isothiocyanates. The present annulation showed broad substrate scope with good functional group tolerance, and was effective on gram scale.

Iron phthalocyanine-derived nanozyme as dual reactive oxygen species generation accelerator for photothermally enhanced tumor catalytic therapy

Nanozymes are artificial enzymes that mimic natural enzyme-like activities and show great promise for tumor catalytic therapy. However, new nanozymes with multiple catalytic activities for multifunctional nanotheranostic use remain challenging to design. Herein, for the first time, iron phthalocyanine (Fe(II)Pc) was assembled with poly(l-lactide-co-glycolide)-block-poly(ethylene glycol) to prepare an Fe(II)Pc assembly (denoted as Fe(II)Pc-A). The obtained Fe(II)Pc-A could be applied as a smart near-infrared (NIR) light-responsive nanotheranostic for simultaneous photoacoustic imaging-guided photothermal therapy. Notably, Fe(II)Pc-A possessed peroxidase, catalase, and oxidase mimicking activities, which could not only catalyze the conversion of intratumoral H2O2 to •OH, but also degrade H2O2 to generate O2 and continuously catalyze the conversion of O2 to cytotoxic O2•-. Impressively, the dual reactive oxygen species (ROS) generation of Fe(II)Pc-A was further remarkably enhanced by the endogenous acidity of the tumor microenvironment and the exogenous NIR light-responsive photothermal effect. Moreover, the O2 self-supplying ability of Fe(II)Pc-A led to increased generation of O2•- for enhancing catalytic therapy in hypoxic tumor. These collective properties of Fe(II)Pc-A nanozyme enabled it to be a dual ROS generation accelerator for photothermally enhanced tumor catalytic therapy. Thus, a new type of high-performance nanozyme for multifunctional nanotheranostic use toward cancer was presented.

Bilayer coatings based on silica materials and iron (III) phthalocyanine – Sensitized TiO2 photocatalyst

This study presents a sol-gel method for preparation of bilayer coatings based on silica materials and iron (III) phthalocyanine - sensitized TiO2 nanoparticles (TiO2–Fe(III)Pc), deposited on glass surfaces. Silica materials were synthetized using organosilane precursors (dimethoxydimethylsilane (DMDMES), octyltriethoxysilane (OTES), and/or hexadecyltrimethoxysilane (HDTMES)), with a two-step acid reaction. The materials properties have been investigated using FT-IR and UV–vis spectroscopy, AFM analysis, and water contact angle. The photo-degradation experiments of thin films were developed using methylene blue as a standard contaminant. FT-IR spectra confirmed the successful grafting of silica materials onto the surface of TiO2–Fe(III)Pc nanoparticles. AFM analysis indicated that the thin films present a different nanostructure depending on the silica matrix and the existence of TiO2–Fe(III)Pc nanoparticles. Contact angle measurements showed that sol-gel coatings exhibit hydrophobic behavior (>99 ± 2°), before and after photo-degradation test. The presence of nanoparticles plays an important role in the development of coatings with photo-catalytic property.

Electrocatalytic reduction of CO2 to CO over iron phthalocyanine-modified graphene nanocomposites

The non-precious materials with iron-pyrrolic nitrogen-carbon (Fe–N–C) moiety have attracted an increasing attention on the CO2 reduction reaction (CO2RR). However, the influence of iron valence state and environmental synergy is not still clear. Here, iron phthalocyanine (FePc) molecule with an intrinsic Fe–N4–C moiety is enough dispersed on graphene as the single-atom iron catalyst through a facile chemical method. The FePc-graphene composites with different FePc content and iron valence state are synthesized to investigate their catalysis for the CO2RR to CO. The onset overpotential of 190 mV and Faradaic efficiency of >90% may be achieved in the optimal composites. Experimental and calculational results prove the positive role and synergy of Fe(II)Pc with Fe(III)Pc and graphene. The formation of ∗COOH intermediate is confirmed to be the rate-limiting step. The theoretical calculation reveals that Fe(II)Pc should have higher activity than Fe(III)Pc, and Fe(II)Pc/FePc(III) dimer may be better than individual one. This work clearly exhibits the effect of Fe2+/3+- pyrrolic N4–C on the CO2RR.

Iron phthalocyanine-sensitized magnetic catalysts for BPA photodegradation

The catalytic behavior of iron phthalocyanine (FePc)-sensitized magnetic nanocatalysts was evaluated for their application in the oxidative treatment of Bisphenol A (BPA) under mild environmental conditions. Two types of FePc (Fe(II)Pc and Fe(III)Pc), which are highly photosensitive compounds, were immobilized on the surface of functionalized magnetite. The nanomaterials were characterized by high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analyses (TGA). The generation of singlet oxygen by nanomaterials was also investigated. In the presence of UVA light exposure (365 nm) and 15 mM H2O2, the M@Fe(III)Pc photocatalyst gave the best results; for a catalyst concentration of 2.0 g L − 1, around 60% BPA was removed after 120 min of reaction. These experimental conditions were further tested under natural solar light exposure, for which also M@Fe(III)Pc exhibited enhanced oxidative catalytic activity, being able to remove 83% of BPA in solution. The water samples were less cytotoxic after treatment, this being confirmed by the MCF-7 cell viability assay.

Phthalocyanine and Metal Phthalocyanines Adsorbed on Graphene: A Density Functional Study

Geometries of phthalocyanine (Pc) and metal (M = Cu, Fe, Zn, and Sn) Pc (MPc) adsorption on graphene have been studied using van der Waals density functional theory, which takes into account nonloc...

Iron Phthalocyanine and Ferromagnetic Thin Films: Magnetic Behavior of Single and Double Interfaces.

Metal-phthalocyanines are quasi-planar heterocyclic macrocycle molecules with a highly conjugated structure. They can be engineered at the molecular scale (central atom, ligand) to tailor new properties for organic spintronics devices. In this study, we evaluated the magnetic behavior of FePc in a ∼1 nm molecular film sandwiched between two ferromagnetic films: cobalt (bottom) and nickel (top). In the single interface, FePc in contact with a Co film is magnetically coupled with the inorganic film magnetization, though the relatively small Fe(Pc) X-ray magnetic circular dichroism (XMCD) signal in remanence, with respect to that observed in applied field of 6 T, suggests that a fraction of molecules in the organometallic film have their magnetic moment not aligned or antiparallel with respect to Co. When in contact with two interfaces, Fe(Pc) XMCD doubles, indicating that part of the Fe(Pc) are now aligned with the Ni topmost layer, saturated at 1 T. We discussed the relevance of the finding in terms of understanding and developing hybrid organic/inorganic spin devices.

(Invited) Nanoscale Electrocrystallization: A Site-Selective Electrochemical π-Figuration of Nanocrystals for Electronic Devices

Efficient nanofabrication is still the problem awaiting solution in the nanotechnology field. Such nanofabrication should involve both economy and ecology-friendly process which produces high performance materials or devices. As seen in semiconductor industry, these fabrication technologies generally consume a large amount of energy under high-vacuum and/or high-temperature conditions. There is a strong need to switch to processes which are both eco-friendly and low-cost. Therefore pinpoint nanofabrication via eco-friendly process seems to be most promising. From the viewpoint, we have developed nanoscale electrocrystallization for nanodevice fabrication.1 This method allows everyone to grow nanocrystals, which consist of π-conjugated molecules, site-selectively within a gap between two electrodes fabricated on a substrate. In addition, this method also allows for the gap between the two electrodes to be bridged by the formed nanocrystals. · Magnetic field effect devices Magnetic field effect devices were designed by using dicyanoiron(III)phthalocyanine ([Fe(Pc)(CN)2]-) tetraphenylphosphonium (TPP+) salt as a starting material of nanoscale electrocrystallization. The electrolysis gave nanocrystals that exhibited a strong correlation between the localized spin and conduction electrons, TPP·[Fe(Pc)(CN)2]2 was obtained. A negative giant magnetoresistance was first observed as an organic nanocrystal.2 Moreover, an angular dependence of the negative giant magnetoresistance that originates from the highly oriented growth of the nanocrystals was also observed. · Electronic field effect devices Electronic field effect devices such as field-effect transistors (FETs) were designed by using materials for organic conductors. A bottom-gate type FET structure was simply obtained when a silicon substrate with oxide layer was used for an electrode substrate. The two electrochemical electrodes were reused as source and drain electrodes. FET characteristics showed current enhancement in some kinds of samples.3 The device fabrication was also demonstrated via an eco-friendly and non-vacuum process using a material printer.4 Further details of fabrication, materials, and physical properties will be reported.

Catalytic selectivity of metallophthalocyanines for electrochemical nitric oxide sensing

The catalytic properties of metallophthalocyanine (MPc) complexes have long been applied to electrochemical sensing of nitric oxide (NO) to amplify sensitivity and reduce the substantial overpotential required for NO oxidation. The latter point has significant ramifications for in situ amperometric detection, as large working potentials oxidize biological interferents (e.g., nitrite, l-ascorbate, and carbon monoxide). Herein, we sought to isolate and quantify, for the first time, the selectivity benefits of MPc modification of glassy carbon electrodes. A series of the most catalytically active MPc complexes towards NO, including Fe(II)Pc, Co(II)Pc, Ni(II)Pc, and Zn(II)Pc, was selected and probed for NO sensing ability under both differential pulse voltammetry (DPV) and constant potential amperometry (CPA). Data from DPV measurements provided information with respect to MPc signal sensitivity amplification (∼1.5×) and peak shifting (100–200 mV). Iron-Pc exerted the most specific catalytic activity towards NO over nitrite. Catalyst-enabled reduction of the working potential under CPA was found to improve selectivity for NO over high potential interferents, regardless of MPc. However, impaired selectivity against low potential interferents was also noted.

Evaluation of the Giant Ferromagnetic π-d Interaction in Iron-Phthalocyanine Molecule.

The interaction between itinerant π and localized d electrons in metal-phthalocyanines, namely, Jπd interaction, is considered as responsible for the giant negative magnetoresistance observed in several phthalocyanine-based conductors, among many other important physical properties. Despite the fundamental and technological importance of this on-site intramolecular interaction, its giant ferromagnetic nature has been only recently demonstrated by the experiments conducted by Murakawa et al. in the neutral radical [Fe(Pc)(CN)2]·2CHCl3 ( Phys. Rev. B 2015 , 92 , 054429 ). In this article, we present the theoretical evaluation of this interaction combining wave function-based electronic calculations on isolated Fe(Pc)(CN)2 molecules and density functional theory-based periodic calculations on the crystal. Our calculations confirm the ferromagnetic nature of the π-d interaction, with a coupling constant as large as Jπd/kB = 570 K, in excellent agreement with the experiments, and the presence of intermolecular antiferromagnetic interactions driven by the π-π overlap of neighboring phthalocyaninato molecules. The analysis of the wave function of the ground state of the Fe(Pc)(CN)2 molecule provides the clues of the origin of this giant ferromagnetic π-d interaction.

Base-controlled Fe(Pc)-catalyzed aerobic oxidation of thiols for the synthesis of S-S and S-P(O) bonds.

Fe(Pc)-Catalyzed aerobic oxidation of thiols for the synthesis of disulfides has been developed under mild reaction conditions. In addition, an aerobic oxidative cross-dehydrogenative coupling (CDC) reaction of thiols with P(O)-H compounds (H-phosphonates and H-phosphine oxide) for the formation of S-P(O) bonds has been demonstrated under the Fe(Pc) catalysis system with a base additive. Control experiments revealed that the use of a base (DIPA) in this system controls the synthetic pathways in which thiophosphates are formed.

Determination of Nitrite from Water Catchment Areas Using Graphite Based Electrodes

In this study, four electrodes based on unmodified graphite (G) and graphite modified with iron (II) phthalocyanine (Fe(II)Pc), nickel (II) phthalolocyanine (Ni(II)Pc) and Chitosan from crab shells (Ch) were compared and evaluated for determination of nitrites in different types of water samples using differential pulse anodic voltammetry. For the Ni(II)Pc modified graphite sensor, a high sensitivity (6.62 × 10−8 A mg L−1) and a lower quantification limit (0.0014 mg L−1) were obtained in comparison with G (sensitivity of 3.23 × 10−8 A mg L−1; LOD of 0.0040 mg L−1 and LOQ of 0.0046 mg L−1) and Fe(II)Pc/G (sensitivity of 3.13 × 10−8 A mg L−1; LOD of 0.0032 mg L−1 and LOQ of 0.0460 mg L−1). For the modified graphite microsensor based on Chitosan from crab shells a lower limit of detection (0.0002 mg L−1) and a lower limit of quantification (0.0005 mg L−1) were obtained. The unmodified graphite microsensor has a detection limit of 0.0040 mg L−1 for nitrite. These microsensors are indeed all suitable and reliable to employ for the assay of nitrite in different types of water samples from aquatic ecosystems in Romania with an RSD less that 0.11%.

Insight into the reactivity difference of two iron phthalocyanine catalysts in chromogenic reaction: DFT theoretical study

ABSTRACTChromogenic reaction catalyzed by metal phthalocyanine (MPc) complexes is a novel and practical method for the facile identification of phenolic pollutants. Exploring the catalytic reaction mechanism is the current concern in the investigation. In this work, tetranitro iron (II) phthalocyanine (TNFe(II)Pc) and iron (II) phthalocyanine (Fe(II)Pc) catalyzed chromogenic reactions were studied at the B3LYP level on the basis of the density functional theory (DFT) calculation. The molecular structure, atomic charge, and frontier molecular orbital of these two kinds of iron phthalocyanine complex were investigated. The calculation results demonstrate that no obvious difference for geometry structures of Fe(II)Pc and TNFe(II)Pc macrocycle can be found, while the atomic charge of Fe atom increases obviously with the four nitro groups substituted on the peripheral of macrocycle. By applying the descriptor of donor–acceptor molecular hardness, the difference of electron transfer from chlorophenol substrates to TNFe(II)Pc/Fe(II)Pc was well explained. Our investigations could provide a new strategy in designing various MPc catalysts for chromogenic identification of chlorophenol pollutants.

Characterization of iron diagenesis in marine sediments using refined iron speciation and quantized iron(III)-oxide reactivity: a case study in the Jiaozhou Bay, China

As a case study, refined iron (Fe) speciation and quantitative characterization of the reductive reactivity of Fe (III) oxides are combined to investigate Fe diagenetic processes in a core sediment from the eutrophic Jiaozhou Bay. The results show that a combination of the two methods can trace Fe transformation in more detail and offer nuanced information on Fe diagenesis from multiple perspectives. This methodology may be used to enhance our understanding of the complex biogeochemical cycling of Fe and sulfur in other studies. Microbial iron reduction (MIR) plays an important role in Fe(III) reduction over the upper sediments, while a chemical reduction by reaction with dissolved sulfide is the main process at a deeper (> 12 cm) layer. The most bioavailable amorphous Fe(III) oxides [Fe(III)am] are the main source of the MIR, followed by poorly crystalline Fe(III) oxides [Fe(III)pc)] and magnetite. Well crystalline Fe(III) oxides [Fe (III)wc] have barely participated in Fe diagenesis. The importance of the MIR over the upper layer may be a combined result of the high availability of highly reactive Fe oxides and low availability of labile organic matter, and the latter is also the ultimate factor limiting sulfate reduction and sulfide accumulation in the sediments. Microbially reducible Fe(III) [MR-Fe(III)], which is quantified by kinetics of Fe(II)-oxide reduction, mainly consists of the most reactive Fe(III)am and less reactive Fe(III)pc. The bulk reactivity of the MR-Fe(III) pool is equivalent to aged ferrihydrite, and shows down-core decrease due to preferential reduction of highly reactive phases of Fe oxides.