Fe Phthalocyanine Research Articles

Toward high permeability, selectivity and controllability of water desalination with FePc nanopores.

Nanoporous materials exhibit promising potential in water transportation applications, especially in ocean water desalination. It is highly desired to have great permeability, selectivity and controllability in the desalination performance of these nanopores. However, it is still a challenge to achieve all three features in one material or device. Here, we demonstrate efficient and controllable water desalination with a nanoporous 2D Fe phthalocyanine (FePc) membrane using molecular dynamics simulations. We find the FePc membrane not only conducts fast water flow, but it also suppresses ion permeation. The selectivity is attributed to a mechanism distinct from the traditional steric exclusion: cations are excluded due to electrostatic repulsion, whereas anions can be trapped in the nanopore and induce the reorganization of ions in the vicinity of the nanopore, which in turn creates a tendency for the trapped anions to move back into the saline reservoir. More interestingly, we find such mechanism is largely due to the sufficiently strong electrostatic interaction of the charged nanopore region with ions and is not restricted to the FePc nanopore. In addition, the number of protonated nitrogen atoms in FePc pores can be modulated by adjusting the pH value of the solution. The extent of the anion occupancy can thus be regulated, giving rise to control of the water flow. Taken together, great permeability, selectivity and controllability can be achieved with this nanosheet system. Moreover, our study suggests there is an alternative mechanism of water desalination which may be realized by intrinsically nanoporous materials such as FePc membranes.

Synergistic Factors Affecting Catalytic Performance of Fe(II) Phthalocyanine @ Titania-Pillared Bentonite Nanocomposites in Styrene Production

Synergistic Factors Affecting Catalytic Performance of Fe(II) Phthalocyanine @ Titania-Pillared Bentonite Nanocomposites in Styrene Production

The electrochemical and spectroelectrochemical properties of metal free and metallophthalocyanines containing triazole/piperazine units

The synthesis and characterization of novel peripherally tetra [1,2,4]-triazole substituted metal-free phthalocyanine and its metal complexes (Zn(II), Ni(II), Pb(II), Cu(II) and Fe(II)) and the investigation of electrochemical and spectroelectrochemical properties of metal-free, Zn(II), Pb(II), Fe(II) phthalocyanines were performed for the first time in this study. Electrochemical characterizations of the complexes were performed with voltammetric and in situ spectroelectrochemical measurements. Voltammetric responses of the complexes supported the proposed structures, since complexes bearing redox inactive Pc ring metal centers just gave Pc based electron transfer reactions, while iron phthalocyanine went to metal based electron transfer reaction in addition to the Pc based ones. Electron withdrawing nature of [1,2,4]-triazole substituents shifted the redox processes toward the positive potentials. All complexes were electropolymerized during the oxidation reactions in dichloromethane (DCM) solvent. Types of the metal center of the complexes altered the electropolymerization reactions of the complexes. Spectra and colors of the electrogenerated redox species of the complexes were also determined with in situ spectroelectrochemical and in situ electrocolorimetric measurements.

FePc/Metal Interfaces Driven by the Electronic States of Different Low-Dimensional Ag Structures Formed on Si(111)

The characteristic electronic structure of low-dimensional Ag structures on semiconductor, i.e., Si(111)-√3 × √3-Ag superstructure and Ag quantum well state (QWS), were used to explore the interaction between two-dimensional electron gas and a metal–organic molecule, Fe–phthalocyanine (FePc), using angle-resolved photoelectron and X-ray absorption (XAS) spectroscopies. The characteristic surface states of the Ag low-dimensional (LD) system close to the Fermi level (EF), produced either by an excess of Ag atoms on the Si(111)-√3 × √3-Ag superstructure or by confinement near the surface as in Ag-QWS, are actively involved in the charge reorganization at the FePc/Ag(LD) interfaces. In the first case, the surface state S1 undergoes a change in its binding energy (BE) and an increase in its electron population; in the latter, the diameter of the Fermi map of the surface state (SS) decreases by 50% suggesting the reduction of its electron population. The two FePc/Ag(LD) systems manifest interface states located...

Electrode Modification Using Alkynyl Substituted Fe(II) Phthalocyanine via Electrografting and Click Chemistry for Electrocatalysis

AbstractIn this work, tetrakis(5‐hexyn‐oxy)Fe(II) phthalocyanine was synthesised in order to perform a click reaction between the terminal alkyne groups and an azide group on a glassy carbon electrode (GCE) surface. An azide group was formed on the electrode surface following electrografting using 4‐azidobenzene diazonium tetrafluoroborate by electrochemical reduction. The Cu(I) catalyzed alkyne‐azide Huisgen cycloaddition reaction was then employed in order to react the terminal alkyne groups on the phthalocyanine with the azide groups on the GCE surface. The modified electrode was employed to catalyse the oxidation of hydrazine. The electrode showed good electrocatalytic ability towards the detection of hydrazine with a sensitivity of 15.38 µA mM−1 and a limit of detection of 1.09 µM.

Mixed configuration ground state in iron(II) phthalocyanine

We calculate the angular dependence of the x-ray linear and circular dichroism at the $L_{2,3}$ edges of $\alpha$-Fe(II) Phthalocyanine (FePc) thin films using a ligand field model with full configuration interaction. We find the best agreement with the experimental spectra for a mixed ground state of $^3E_{g}(a_{1g}^2e_g^3b_{2g}^1)$ and $^3B_{2g}(a_{1g}^1e_g^4b_{2g}^1)$ with the two configurations coupled by the spin-orbit interaction. The $^3E_{g}(b)$ and $^3B_{2g}$ states have an easy axis and plane anisotropies, respectively. Our model accounts for an easy-plane magnetic anisotropy and the measured magnitudes of the in-plane orbital and spin moments. The proximity in energy of the two configurations allows a switching of the magnetic anisotropy from easy plane to easy axis with a small change in the crystal field, as recently observed for FePc adsorbed on an oxidized Cu surface. We also discuss the possibility of a quintet ground state ($^5A_{1g}$ is 250~meV above the ground state) with planar anisotropy by manipulation of the Fe-C bond length by depositing the complex on a substrate that is subjected to a mechanical strain.

Molecular tilting and columnar stacking of Fe phthalocyanine thin films on Au(111)

Scanning tunneling microscopy and x-ray absorption spectroscopic results at the Fe K edge of Fe phthalocyanine (FePc) thin films grown on Au substrates, together with theoretical calculations, allow us to refine the structure of the film. In particular, we show that the columnar stacking of the FePc molecules is different from that found in bulk α and β phases. Moreover, the molecules do not lay parallel to the surface of the substrate. These structural findings are relevant to understand magnetism of FePc films.

Co(II) and Fe(II) phthalocyanines: synthesis, investigation of their catalytic activity towards phenolic compounds and electrochemical behaviour

4‐[(1‐Benzylpiperidin‐4‐yl)oxy]‐substituted cobalt(II) and iron(II) phthalocyanine complexes were synthesized and their catalytic activity towards various phenolic compounds was investigated. Converting from environmentally harmful phenolic compounds into less harmful oxidation products using phthalocyanines makes this study attractive. This catalysis is feasible and time‐saving in terms of procedure and the best oxidation conditions determined. Electrochemical studies were also carried out using cyclic voltammetry and square wave voltammetry techniques. Voltammetric analyses of the synthesized phthalocyanine complexes supported their proposed structures. Copyright © 2015 John Wiley & Sons, Ltd.

Synthesis, electrochemistry and In situ spectroelectrochemistry of novel tetra dimethyl 5-oxyisophthalate substituted Co(II), Mn(III), and μ-oxo-dimer Fe(III) phthalocyanines

In this study, peripheral and non-peripheral tetra dimethyl 5-oxyisophthalate substituted cobalt(II), manganese(III) and μ-oxo-dimer Fe(III) phthalocyanines were synthesized by the reaction of dimethyl 5-hydroxyisophthalate with 1,2-dicyano-4-nitrobenzene/1,2-dicyano-3-nitrobenzen in dry N,N-dimethylformamide in the presence of anhydrous potassium carbonate. All purified phthalocyanine compounds were characterized by using FT-IR, UV–visible, MALDI-TOF mass spectrometry and elemental analyses results. Electron transfer properties of all novel cobalt(II), manganese(III) and μ-oxo-dimer Fe(III)phthalocyanine complexes were investigated by voltammetric and in situ spectroelectrochemical measurements in nonaqueous solution medium. Complexes were observed to display both metal-based and phthalocyanine ring-based reduction and oxidation electron transfer processes.

Facile synthesis of highly active Co(II) and Fe(II) phthalocyanine catalysts for aerobic oxidation of phenolic compounds

In this work, 2,3-dichlorophenoxy substituted cobalt and iron phthalocyanines have been synthesized and used as efficient catalysts for aerobic oxidation of nitrophenols. Co(II) and Fe(II) phthalocyanines have been characterized by IR, 1H NMR, 13C NMR, UV–vis, and mass spectroscopies. tert-butyl hydroperoxide (TBHP), m-chloroperoxybenzoic acid, hydrogen peroxide, and air oxygen have been used as oxygen source. These catalysts offered the highest activity on 4-nitrophenol oxidation in 3 h. In order to achieve the best reaction conditions, oxidant ratio, temperature, and oxidant type have been investigated with different nitrophenols in 3 h.

Synthesis, characterization and gas sensing properties of novel homo and hetero dinuclear ball-type phthalocyanines.

New ball-type homodinuclear Co(ii)-Co(ii) phthalocyanine () and ball-type heterodinuclear Co(ii)-Fe(ii) phthalocyanine () were synthesized from the corresponding [2,10,16,24-tetrakis{4,4'-cyclohexylidenebis(2-cyclohexyphenoxyphthalonitrile)}phthalocyaninatocobalt(ii)] (). The novel compounds have been characterized by elemental analysis, IR, UV-Vis and MALDI-TOF mass spectroscopy. Gas sensing capability of the spin coated film of and were studied using amperometric technique at various temperatures. For a better understanding of the interaction of and films with organic compounds, two different groups of compounds (aromatics and alcohols) were selected as test analytes. It was observed that the operating temperature had a considerable effect on the gas sensing performance of the sensors investigated. The experimental results show that film offers a promising perspective as a sensing material for the detection of relatively low aromatic vapours even at room temperature. This suggests that aromatics might be distinguished from alcohols. The obtained data were analysed using two different adsorption kinetic models: the pseudo first order equation and Elovich equation to determine the best fit equation for the adsorption of toluene vapor onto and films. The first-order equation was the best of the various kinetic models studied to describe the adsorption kinetic of toluene on Pc films at higher concentrations, as evidenced by the highest correlation coefficients. In addition, it was observed that Elovich equation generates a straight line that best fit to the data of adsorption of lower concentrations of toluene.

Tailoring molecular architectures of Fe phthalocyanine on nanocarbon supports for high oxygen reduction performance

Tailored molecular architectures of FePc on nanocarbon supports from nanorods to uniform shells exhibit excellent electrocatalytic activity for the oxygen reduction reaction in alkaline solution.

Fe Phthalocyanine-Based Catalyst for the Electro-Oxidation of N,N-Diaminourea and Hydrazine and Its Application in an Anion-Exchange Membrane Fuel Cell

We present a carbon-supported iron phthalocyanine catalyst for the electro-oxidation of N,N-diaminourea (DAU), a hydrazine derivative. This catalyst can oxidize DAU, which is scarcely oxidized by conventional metal electrodes. The onset potential reaches 0.3 V vs. a reversible hydrogen electrode, and the oxidation current of DAU is comparable to that of hydrazine. The activity of Co phthalocyanine was also examined; the Fe phthalocyanine catalyst exhibited a higher oxidation current for DAU than the Co phthalocyanine catalyst. The dependence of the activity on the concentration of DAU suggests that DAU forms a complex with Fe phthalocyanine. Based on this concentration-dependence and an HPLC (high performance liquid chromatography) analysis of DAU hydrolysis, it was shown that hydrolysis of DAU in an electrolyte solution does not significantly affect the electro-oxidation of DAU by a carbon-supported Fe phthalocyanine. We made an anion-exchange membrane fuel cell that incorporates Fe phthalocyanine as an anode catalyst. This cell delivered considerable electricity when DAU was supplied as a fuel (open circuit potential: 0.59 V, short circuit current: 69 mAcm−2 at room temperature).

Synthesis, electrochemistry of metal-free, copper, titanium phthalocyanines and investigation of catalytic activity of cobalt, iron phthalocyanines on benzyl alcohol oxidation bearing 4-{2-[3-trifluoromethyl)phenoxy]ethoxy} groups

The synthesis, characterization of novel peripherally 4-{2-[3-trifluoromethyl)phenoxy]ethoxy} groups substituted metal-free, Cu(II), Ti(IV), Co(II), Fe(II) phthalocyanines have been reported for the first time in this study. All the new compounds were characterized by a combination of IR, 1H NMR, 13C NMR, mass and UV–vis spectroscopy techniques. Electrochemical studies of TiIVOPc, H2-Pc, CuIIPc were examined by using cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques. Voltammetric analyses of phthalocyanines supported the proposed structure of the synthesized complexes. While H2Pc and CuIIPc showed only ligand based reduction reactions, TiIVOPc showed metal based and ligand based reduction reactions as expected. In addition, new Co(II) and Fe(II) phthalocyanine complexes (5,6) were investigated as a catalyst for the oxidation of benzyl alcohol. The influence of substrate/catalyst ratio, temperature, oxidant ratio and oxidant type were also investigated to find optimal reaction on benzyl alcohol oxidation for getting the highest conversion.

Sulfonamide-substituted iron phthalocyanine: design, solubility range, stability and oxidation of olefins.

4-tert-Butylbenzenesulfonamide was used as a substituent of tetra peripherally substituted Fe(ii) phthalocyanine, taking into account several parameters crucial for the design of potential oxidation catalysts such as solubility and stability. The resulting phthalocyanine exhibits a remarkable stability under oxidative conditions. The main product of the oxidation of cyclohexene using H2O2 as the oxidant is the allylic ketone, 2-cyclohexen-1-one. Styrene oxidation led mainly to the formation of benzaldehyde.

Reactivity trends of Fe phthalocyanines confined on graphite electrodes in terms of donor–acceptor intermolecular hardness: Linear versus volcano correlations

In this work, we have studied the interaction between the hydrazine N2H4 molecule with several FeN4 macrocyclic complexes (FePc's). In order to modulate the electron density located on the metal center using iron-phthalocyanine (FePc) as the reference, we used substituted iron-phthalocyanines with different types of substituents electron-donating groups such as iron-tetraamino-phthalocyanine (4β(NH2)FePc) and iron-octamethoxyphthalocyanine (8β(OCH3)FePc), and with electron-withdrawing groups such as iron-tetranitrophthalocyanine(4β(NO2)FePc) and iron-hexadecachlorophthalocyanine (16(Cl)FePc), respectively.We have found that the energy of interaction between hydrazine and the Fe center in the macrocycle increases as the electron-withdrawing power of the substituents increases. When rate constants instead of currents are compared in a semilog plot versus ΔɛD-A, a linear correlation is found where logk increases as the intermolecular hardness of the systems decreases.

Ferromagnetic Exchange Coupling between Fe Phthalocyanine and Ni(111) Surface Mediated by the Extended States of Graphene

The interface spin coupling mechanism is studied in a hybrid structure made of Fe phthalocyanine molecules sublimed in ultrahigh vacuum on graphene grown on the magnetic substrate Ni(111). By using synchrotron X-ray magnetic circular dichroism, the field-dependent magnetization of the isolated FePc molecules and of the Ni substrate has been measured at low temperature (8 K). Along with density functional theory calculations, the role of the graphene interlayer in transmitting the magnetic coupling is addressed. Both experiments and theory show a ferromagnetic coupling between the molecules and the substrate which is weakened by the insertion of graphene. DFT calculations indicate that the key role is played by the π orbitals of graphene, which hybridize with the underlying magnetic Ni, giving rise to a sizable spin polarized continuum at the molecular interface. The resulting overlap with the Fe orbitals favors a direct coupling of ferromagnetic nature, as evidenced by our spin density distribution plots.

ELECTROCATALYTIC ACTIVITY FOR O2 REDUCTION OF UNSUBSTITUTED AND PERCHLORINATED IRON PHTHALOCYANINES ADSORBED ON AMINO-TERMINATED MULTIWALLED CARBON NANOTUBES DEPOSITED ON GLASSY CARBON ELECTRODES

ABSTRACT Amino-functionalized multiwalled carbon nanotubes (MWCNT-NH 2 ) were modifiedwith Fe phthalocyanine (FePc) and perchlorinated Fe phthalocyanine (16(Cl)FePc) and deposited on glassy carbon electrodes (GCE). The electrocatalytic activity of these hybrid electrodes was examined for the reduction of molecular oxygen in alkaline media (0.2 M NaOH) using stationary and rotating disk electrodes. Electrodes containing 16(Cl)FePc are more active than those containing FePc. Electrodes containing CNTs are more active than electrodes without CNTs but the higher activity can be attributed to a greater real surface area, compared CGEs and not necessarily to a catalytic effect. Keywords: Amino-terminated carbon nanotubes, Fe phthalocyanines, O2 reduction, catalytic activity. INTRODUCTION MN4 macrocyclic metal complexes are well known as catalyst for many electrochemical reactions, specially the reduction of O 2 and their activity is directly related 6,7to their redox properties . On the other hand, carbon nanotubes (CNTs) 8are interesting support materials for the modificationof substrates. CNTs increase the area of the electrodes and when this is combined with MN4 macrocyclic complexes 7,9-13substantial improvements in the reactivityare observed. The specificchemistry of the surface of CNTs can be tailored by changing the nature of surface groups that can be created on their surface by appropriate chemical treatment, 8-13adapting them for a desired application . A non-chemical way of modificationof CNTs is by simple adsorption of macrocyclic complexes on the external walls of the CNTs where the molecules stick to them by π-π interactions. If carbon nanotubes are modifiedwith amino groups -NH

In Search of the Best Iron N4-Macrocyclic Catalysts Adsorbed on Graphite Electrodes and on Multi-walled Carbon Nanotubes for the Oxidation of l-Cysteine by Adjusting the Fe(II)/(I) Formal Potential of the Complex

The redox potential of macrocyclic complexes is a very predictive reactivity index for the electrocatalytic activity of these molecules, and it can be easily measured under the same conditions of the catalysis experiments. It reflects directly the activity of a given complex. We have investigated the effect of the Fe(II)/(I) formal potential on the catalytic activity of a series of Fe porphyrins and Fe phthalocyanines for the electrooxidation of l-cysteine, with the complexes directly adsorbed on ordinary pyrolytic graphite or adsorbed on multi-walled carbon nanotubes (MWCNTs) deposited on graphite. A correlation of log j (at constant potential) versus the Fe(II)/(I) formal potential of the catalysts gives a volcano curve for both systems without and with MWCNTs with higher activities in the latter case. Our results clearly show that the highest catalytic activity is achieved in a rather narrow potential window of Fe(II)/(I) formal potentials of N4-macrocyclic complexes. The use of MWCNTs as supporting material for the catalysts does not change the reactivity trends of the Fe complexes.

Fe phthalocyanine on Co(001): Influence of surface oxidation on structural and electronic properties

The adsorption of FePc on Co(001) and $c$$(2\ifmmode\times\else\texttimes\fi{}2)$O/Co(001) was studied by means of density functional theory calculations, taking into account the long range van der Waals dispersion forces. Several high symmetry adsorption sites were analyzed, together with two possible orientations of the molecules. For the adsorption of FePc on the bare surface the on-top-of Co position, rotated by 45${}^{\ensuremath{\circ}}$ relative to the substrate orientation, is most stable, whereas on the surface covered by an O adlayer the on-top-of O position is preferred. This has strong impact on the magnetic coupling but leaves the spin state of $S=1$ unaltered. The total energies of the studied adsorption sites on the bare metal differ by at least 0.75 eV and are characterized by a strong hybridization of the carbon atoms in the peripheral benzenic rings with the Co atoms beneath. In the presence of the O adlayer the various sites are closer in energy, which turns out to be related to the screening of the ferromagnetic film by the oxygen atoms.