Magnesium Phthalocyanine Research Articles

Formation of Magnesium and Chloroaluminium Phthalocyanine Thin Films Exhibiting an Intense Near-Infrared Absorption by Electrolysis of Surfactants with Ferrocenyl Moiety

Abstract Magnesium or chloroaluminium phthalocyanine (1 and 2) was dispersed to the micellar solution formed by a non-ionic surfactant with ferrocenyl moiety (3). The thin films prepared by the controlled-potential electrolysis of the micellar solution exhibited an intense nearinfrared absorption.

Electrochemistry and spectroscopy of magnesium phthalocyanine. Analysis of the absorption and magnetic circular dichroism spectra

Electrochemistry and spectroscopy of magnesium phthalocyanine. Analysis of the absorption and magnetic circular dichroism spectra

Spectroscopic studies of phthalocyanines and their clusters with small molecules

van der Waals clusters of free base phthalocyanine (H2Pc) and magnesium phthalocyanine (MgPc) with small hydrocarbons [CnH2n+2(n=1,2,3)], hydrogen bonding solvents (H2O, MeOH, EtOH), and CO2 are studied in the gas phase using supersonic molecular jet spectroscopy. Fluorescence excitation spectra of the cluster systems are characterized in the 000 regions of the cluster S1←S0 transitions. Forbidden low frequency cluster chromophore out-of-plane vibronic transitions are induced by clustering in the majority of the cluster systems studied. This low frequency motion is characterized using an out-of-plane normal coordinate analysis on the H2Pc moiety. Calculations of the binding energy and ground state geometry for the clusters are carried out employing Lennard-Jones (6-12-1) and hydrogen bonding (10-12-1) potentials. Comparison between the calculations and experiments allow for the identification of specific configurations responsible for the cluster vibronic transitions observed. The cluster vibronic spectra and theoretical calculations suggest that stable H2Pc and MgPc solvation sites are located over the phthalocyano core and not over peripheral ring centers. The H2Pc/hydrocarbon cluster experimental and calculational results parallel those obtained for benzene and N-heterocycle/hydrocarbon clusters studied previously. The H2Pc and MgPc/alcohol cluster spectra and calculated geometries suggest that the solvent OH group is intimately involved in the intermolecular interactions and contributes significantly to the observed spectroscopic shifts.

Reversible oxidation and rereduction of magnesium phthalocyanine electrodes. Electrochemical behavior and in situ Raman spectroscopy

Reversible oxidation and rereduction of magnesium phthalocyanine (MgPc) thin films (1000-2000 A thick) on gold electrodes have been observed in the potential range from 0.0 to 0.9 V vs. SCE in various electrolytes, including aqueous NaCl, NaNO/sub 3/, NaClO/sub 4/, and potassium hydrogen phthalate (KHP). In situ Raman spectra recorded during oxidation and rereduction show spectral changes in the 400-1800-cm/sup -1/ range that can be related to the vibrational modes of ring structures in MgPc, hence the oxidation seems to occur in the ligand. The spectroscopic results unambiguously demonstrate the movement of anions into and out of the electrode during oxidation and rereduction processes. Both cyclic voltammetry and chronocoulometry showed that smaller anions allow full oxidation at rapid rates, whereas larger ones inhibit the oxidation, at least with respect to rate. Auger electron spectrometry showed that anions appear to be homogeneously distributed in partially oxidized films.

EFFICIENT PHOTOREDUCTION OF METHYLVIOLOGEN BY METALLOPHTHALOCYANINE SENSITIZERS

Abstract— Metallophthalocyanines (MPc) and tetrasubstituted magnesium phthalocyanines (MgPcR4) were investigated as sensitizers for the photoreduction of methylviologen (MV2+) under visible light(420–800 nm) irradiation using disodium ethylenediaminetetraacetic acid (Na2EDTA) as an electron donor in dimethyl formamide (DMF)‐water mixture. Magnesium phthalocyanine and aluminium phthalocyanine were found to be the most efficient sensitizers among nine MPc's examined (M = 2Li, 2Na, Mg, Ca, Al(Cl), Fe, Ni, Co, and Zn). The following sequence of the efficiency among MgPc and MgPcR4's was obtained.

Gas-induced electrical conductivity changes in metal phthalocyanines

The effect of NO 2, NO, F 2, BCl 3, BF 3, NH 3, H 2S, SO 2 and HCl at low concentrations (< 1 ppm) in air on the eletrical conductivity of a number of metal phthalocyanines has been investigated. Vacuum sublimed films of Pb, Zn, Cu, Ni, Co and Fe phthalocyanine have been shown to be sensitive to NO 2 and F 2 but insensitive to more weakly electrophilic and electrophobic gases. Increasing sensitivity to NO 2 was observed as phthalocyanines containing progressively heavier metals were used. Magnesium phthalocyanine was affected only by HCl. The potential of these materials as gas sensors is discussed.

Solvent-induced dimorphic transformation in magnesium phthalocyanine and its effect on the photoactivity

Sublimed films of α form magnesium phthalocyanine (α-MgPc) can be induced to undergo a dimorphic phase change under the influence of methylene chloride vapours. The vapour-treated film exhibits, in addition to the Q absorption band, an intense near-IR peak at 830 nm whose absorption coefficient was estimated to be 1.0 × 10 5 cm −1. Electron microscopy observation revealed that the small granular particles of α-MgPc change upon solvent exposure to large slender crystallites. The solvent-induced dimorphic transformation of MgPc is also associated with a dramatic enhancement in photoactivity, shown in a photovoltaic device with a CdS/MgPc heterojunction.

Unit cell parameters for a new crystalline polymorph of lead phthalocyanine and for two polymorphs of magnesium phthalocyanine

Unit cell parameters for a new crystalline polymorph of lead phthalocyanine and for two polymorphs of magnesium phthalocyanine

Purification and characterization of phthalocyanines

The technical details of a simple train sublimation (carrier gas) system for purification of organic materials are given and the refining procedure is described. A study of the effects of purification on metal free phthalocyanine (H2Pc), magnesium phthalocyanine (MgPc), copper phthalocyanine (CuPc), vanadyl phthalocyanine (VOPc), zinc phthalocyanine (ZnPc) and lead phthalocyanine (PbPc) was carried out by means of optical absorption, X-ray diffraction, electron paramagnetic resonance, sublimation behaviour and photovoltaic data. It was found that train sublimation improves the quality of the pigments considerably. Spectroscopic results indicate the presence of a second phase in the purified MgPc.

The effect of the metal atom on the absorption spectra of phthalocyanine films

The visible and near ultraviolet absorption spectra have been measured for thin films of H2Pc [C32H18N8], MgPc, FePc, CoPc, CuPc, and ZnPc. Magnesium and iron phthalocyanine have very different absorption spectra. For most of the phthalocyanines, structure of magnitude 0.21 eV is seen on the visible and Soret bands. A d band is indicated in the region 4.0–4.7 eV. This is the spectral region most sensitive to substitutions of the central metal atom.

Photoelectric properties of CdS–MgPc heterojunction solar cells

Heterojunction organic solar cells made by sequential deposition of very thin films of cadmium sulfide (CdS) and magnesium phthalocyanine (MgPc) onto a conductive glass substrate have been studied. The short circuit photocurrent Isc under AMO illumination approached 160 μA/cm2 and an open circuit voltage of 0.69 V was obtained. The fill factor ff ranged from 20% to 40%. The action spectra and capacitance-voltage measurements indicated that the active region is located within the MgPc film at the CdS–MgPc interface. The optimum thickness of the CdS and MgPc layers have been found to be 100 and 60 nm, respectively. A band model of the heterojunction is proposed, which accounts for the observed results.

A spectroscopic study of the complexing ability of metal phthalocyanines with formic acid

The behavior of magnesium, iron and zinc phthalocyanines with formic acid has been studied in detail by i.r. spectroscopy. The results show that magnesium and zinc phthalocyanines adsorb formic acid vapors under a dissociated form, while only physisorption occurs with iron phthalocyanine. This latter phthalocyanine does not show any sign of interaction with formic acid in dilute CCl 4 solutions. The results are compared to previous studies and are discussed in terms of a valence bond model and a molecular orbital model.

Photoreduction of methyl viologen sensitised by the excited singlet state of a magnesium phthalocyanine

Download options Please wait... Article information DOI https://doi.org/10.1039/F29817701175 Article type Paper Download Citation J. Chem. Soc., Faraday Trans. 2, 1981,77, 1175-1187 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Photoreduction of methyl viologen sensitised by the excited singlet state of a magnesium phthalocyanine A. Harriman, G. Porter and M. Richoux, J. Chem. Soc., Faraday Trans. 2, 1981, 77, 1175 DOI: 10.1039/F29817701175 To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Search articles by author Anthony Harriman George Porter Marie-Claude Richoux

Depletion layer studies in organic films: Temperature dependence studies of low frequency capacitance measurements in tetracene and magnesium phthalocyanine

The voltage dependence of capacitance in two photovoltaic sandwich cells, (Al ‖ tetracene ‖ Nesatron) and (Al ‖ magnesium phthalocyanine ‖ Nesatron), is reported as a function of temperature. The tetracene cell shows a voltage independent (geometric) capacitance at room temperature which upon heating to 120 °C changes to a depletion layer type capacitance at 10−1 Hz. Values for depletion width, carrier concentration, and barrier voltage are consistent with those reported in a previous publication where carriers in tetracene were mobilized by light. Magnesium phthalocyanine cells, on the other hand, show a depletion layer capacitance at room temperature and upon cooling revert to a geometric capacitance at some lower temperature depending on the frequency of the measurement. A theoretical treatment is presented which describes the frequency and temperature dependence of the depletion layer capacitance. From this analysis a method for measuring activation energies and rate constants for detrapping is obtained. This method is demonstrated for magnesium phthalocyanine cells.

A spectroscopic study of complexation of phthalocyanines with pyridine

The ability of solid films of phthalocyanines to form complexes when exposed to pyridine vapours was investigated on the basis of assignments of i.r. spectra. Pyridine was found to form a five-and a six-coordinated complex with iron and zinc phthalocyanines, respectively, but it did not interact with the copper or metalfree compound. It was, however, physisorbed to magnesium phthalocyanine. In solution iron phthalocyanine proved capable of forming a 1-1 as well as a 1–2 complex with pyridine, both equilibrium constants being 2.10 2 M −1 in CCl 4. The 1-1 complex appeared instantaneously, whereas the 1–2 complex was formed in a reaction having a rate constant of 0.1 h −1 at room temperature.

Photoconduction in magnesium phthalocyanine thin films

This paper describes the photovoltaic properties of glass/Au/MgPc/Al cells. High quantum yields were obtained with an applied voltage and moderate yields at short circuit. No evidence of a Schottky barrier or p-n junction was observed.

Spectral sensitization of the heterogeneous photocatalytic oxidation of hydroquinone in aqueous solutions at phthalocyanine-coated titanium dioxide powders

Abstract : The photocatalyzed reaction of hydroquinone with oxygen at TiO2 (anatase) powders coated with metal-free or magnesium phthalocyanine under irradiation with light of energy less than the TiO2 band gap is described. The behavior at the powders is correlated with current-potential curves at single crystal n-type TiO2 electrode and an energy level scheme for the reaction is proposed. (Author)

A spectroscopic study of the complexation of phthalocyanines with water, ethanol and phenol

Abstract Assignments are collected for the i.r. spectra of solid films of phthalocyanines in their α and β modifications. On the basis of changes in these spectra the ability to form complexes with vapours of water, ethanol and phenol was investigated. All these species were found to be able to form hydrogen bonds to a nitrogen atom in the magnesium phthalocyanine molecule. Only phenol was found to adhere to zinc phthalocyanine but presenting a case of physisorption. There was, however, also signs of an interaction taking place between the zinc compound and water vapour. None of the vapours showed ability to interact with the iron, copper or metal-free phthalocyanine. The iron but not the metal-free compound proved capable of forming a complex, 1: 1, with water in a CCl4 solution.

Laser properties of some phthalocyanines

The lasing behavior of solutions of the phthalocyanines of aluminum, gallium, magnesium, and zinc was studied with nitrogen laser optical pumping. Aluminum phthalocyanine chloride showed simultaneous lasing at two wavelengths separated by approximately 70 nm. Gallium, magnesium, and zinc phthalocyanine each lased at only one wavelength. This behavior is explained in terms of some of the intrinsic physical properties of these phthalocyanines.

ChemInform Abstract: (25)MG AND (14)N NUCLEAR QUADRUPOLE RESONANCES IN CHLOROPHYLL‐A AND MAGNESIUM PHTHALOCYANINE

Chemischer InformationsdienstVolume 6, Issue 28 Physical Organic Chemistry ChemInform Abstract: (25)MG AND (14)N NUCLEAR QUADRUPOLE RESONANCES IN CHLOROPHYLL-A AND MAGNESIUM PHTHALOCYANINE O. LUMPKIN, O. LUMPKINSearch for more papers by this author O. LUMPKIN, O. LUMPKINSearch for more papers by this author First published: July 15, 1975 https://doi.org/10.1002/chin.197528067AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume6, Issue28July 15, 1975 RelatedInformation