Study of the factors affecting the photoelectrode characteristics of a perylene/phthalocyanine bilayer working in the water phase

Some types of phthalocyanines (MPc (M = H(2), Cu, or Zn), a p-type semiconductor) were used in combination with 3,4,9,10-perylenetetracarboxyl-bisbenzimidazole (PTCBI, an n-type semiconductor), with which those photoelectrode characteristics in the water phase were investigated in terms of kinetics. Each film of the PTCBI/MPc bilayer functioned as a photoanode, where the photoinduced oxidation of thiol occurs at the MPc/water interface along with the hole conduction through the MPc layer. The holes originate on account of the photophysical events in the p/n interior, involving the charge separation of excitons at the p/n interface. The typical photoelectrochemical characteristic in the PTCBI/MPc photoanodes involved a transient photocurrent occurring in the initial stage under illumination (under potentiostatic conditions): thereafter, it attained a steady state. Moreover, both the initial spiky photocurrents and the steady-state photocurrents exhibited saturation at higher concentrations. An analysis with photoelectrode kinetics was performed by assuming an adsorption step prior to a rate-limiting charge transfer step, where equations were applied to photocurrents based on the Langmuir adsorption equilibrium. The kinetic analyses evidently showed that the photoanodic reactions are kinetically dominated by the charge transfer between MPc and thiol, where the overall kinetics for thiol oxidation decreases in the following order: H(2)Pc > ZnPc > CuPc; that is, it appeared that H(2)Pc acts as the more efficient photofunctional interface capable of oxidation in the water phase when PTCBI was concurrently employed as an electron conductor. Considering that the photocurrent generated is proportional to the surface concentration of thiol (Gamma) at the MPc as well as the intrinsic oxidation rate (cf., ZnPc > H(2)Pc approximately CuPc), the higher efficiency in the output at the H(2)Pc surface was attributed to an exceptionally high Gamma (i.e., from the kinetic analyses, the Gamma value at the H(2)Pc surface was also inferred to be 2-3 times higher than that at the other MPcs). Through the present kinetic analysis, it also revealed that the activity for thiol oxidation taking place at Pc ring is comparable to that at the conventional active catalysts (i.e., polycarboxyphthalocyaninato Co(ii) and Fe(iii)) where a central metal is an active site.     

Atypical Film-Forming Behavior of Soluble Tetra-3-Nitro-Substituted Copper Phthalocyanine

Thin films of metal phthalocyanines (MPc) are known to exhibit excellent physical properties but poorly controlled morphologies. Therefore, the present work seeks to understand the film growth mechanism of a model compound for potentially usable MPc, specifically, copper tetra(3-nitro-5-tert-butyl)phthalocyanine (CuPc*). The Langmuir-Schaefer (LS) technique was applied to prepare a series of CuPc* films under different processing conditions. The film growth was examined by Brewster angle microscopy (BAM) on the water surface and small-angle X-ray scattering (SAXS) from the solid films. Neutron reflectometry (NR) measurements of the water uptake into the films and computer simulation of hydrated CuPc* were performed to substantiate an idea of colloidal MPc-water aggregates as nanoscale precursors of smooth solid films. This idea appears fruitful in terms of materials chemistry.     

Electrophoretic deposition of phthalocyanine in organic solutions containing trifluoroacetic acid

The absorption spectra of copper phthalocyanine (CuPc) 1,2-dichloroethane (DCE) solutions containing trifluoroacetic acid (TFAA) shows that the number of protons coordinating to the CuPc molecule was 1 and 2 for the first and second proton adducts, respectively, which indicates the formations of CuPcH(+) and CuPcH(2)(2+). This CuPc molecule may act as a catalyst to dissociate TFAA into trifluoroacetate anion (A(-)) and H(+) and form the proton adducts. The electrical conductivity dependence of the solution on CuPc concentration also supports this mechanism. A dense film of CuPc was deposited on an indium tin oxide cathode plate by electrophoresis of the solution. Similar dense films of a wide variety of phthalocyanines (MPc; M = Cu, H(2), Fe, Ni, Zn, Pb, VO) were also deposited using this method. Similar films of CuPc were also formed using dichloromethane (DCM) and 1,1,1-trichloroethane (TCE) in place of DCE. Depositions are ascribed to the migration of positively charged monomers (i.e., protonated MPc). Scanning electron microscopy revealed that these films are composed of fibrous crystallites, size of which was found to increase with the electrophoresis time, the strength of the applied electrical field and the concentration of CuPc in the bath. The influence of the dielectric constant of the organic solvent on the film growth is discussed.     

Molecule-substrate interaction channels of metal-phthalocyanines on graphene on Ni(111) surface

Molecule-substrate interaction channels of metal-phthalocyanines (MPcs, including NiPc, CuPc, ZnPc, FePc, and CoPc) on graphene on Ni(111) were investigated by employing high-resolution electron energy loss spectroscopy (HREELS). Except the expected IR-active modes, some Raman-active modes were also observed in all of MPcs, which are considered in this study. From the origination of the Raman-active features, it was deduced that MPcs are coupled with the substrate mainly through their central metal atom. The Raman-active modes appear as symmetric peaks in the HREELS in the case of MPcs with Ni, Cu, and Zn, whereas they are asymmetric and appear as a Fano line shape in the case of MPcs with Fe and Co. This spectroscopic difference indicates that the molecule-substrate coupling is completely different in the two cases mentioned above. The molecule-substrate interaction strength is considerably weak and comparable with the π-π interaction between molecules in the case of MPcs with Ni, Cu, and Zn, whereas it is much stronger in the case of MPcs with Fe and Co. From the HREELS observations, it can be suggested that the whole molecule can be effectively decoupled from the underneath Ni(111) by inserting a single layer of graphene between them in the case of MPcs with Ni, Cu, and Zn, whereas only benzene rings can be completely decoupled in the case of MPcs with Fe and Co.     

Metallophthalocyanines Bearing Polymerizable {[5‐({(1E)‐[4‐(Diethylamino)phenyl]methylene}amino)‐ 1‐naphthy1]oxy} Groups as Electrochemical Pesticide Sensor

The synthesis and characterization of novel metallophthalocyanines (MPcs(ea)) carrying {[5‐({(1E)‐[4‐(diethylamino)phenyl]methylene}amino)‐1‐naphthyl]oxy} groups on four peripheral positions have been reported. These complexes have been characterized by a combination of FT‐IR, ¹H and ¹³C NMR, mass and UV‐Vis spectroscopy techniques. Redox active metal centers in the core of the Pc rings (Co (II) [CoPc(ea)], Mn(III) [Cl–MnPc(ea)], and Ti(IV)O [TiOPc(ea)]) and electropolymerizable substituents on the peripheral positions of Pc rings were used to increase redox activity and electrochemically polymerization ability of the complexes. The redox properties of MPcs(ea) were determined with voltammetry and in situ spectroelectrochemistry techniques. Then, GCE/MPc(ea) electrodes were constructed with the electropolymerization of MPcs and these electrodes were tested as the pesticide sensors. Sensing studies indicated that type of the metal center of the complexes effectively influenced the sensing activities. While all complexes showed interaction abilities for the fenitrothion, parathion and eserine, GCE/CoPc(ea) electrode detected the parathion selectively with LOD value of 4.52×10⁻⁷ mol dm⁻³ among studied three pesticides. Moreover, GCE/MnClPc(ea) electrode selectively detected eserine with LOD value of 6.43×10⁻⁷ mol dm⁻³ and GCE/TiOPc(ea) electrode detected parathion with LOD value of 8.64×10⁻⁷ mol dm⁻³. All GCE/MPcs(ea) electrodes showed high sensitivity and wide linear ranges for those pesticides. These sensing data illustrated the usability of these modified electrodes in real samples such as seawater with good selectivity and sensitivity.     

Correlation between molecular orbitals and doping dependence of the electrical conductivity in electron-doped metal-phthalocyanine compounds

We have performed a comparative study of the electronic properties of six different electron-doped metal-phthalocyanine (MPc) compounds (ZnPc, CuPc, NiPc, CoPc, FePc, and MnPc), in which the electron density is controlled by means of potassium intercalation. Despite the complexity of these systems, we find that the nature of the underlying molecular orbitals produces observable effects in the doping dependence of the electrical conductivity of the materials. For all the MPc's in which the added electrons are expected to occupy orbitals centered on the ligands (ZnPc, CuPc, and NiPc), the doping dependence of the conductivity has an essentially identical shape. This shape is different from that observed in MPc materials in which electrons are also added to orbitals centered on the metal atom (CoPc, FePc, and MnPc). The observed relation between the macroscopic electronic properties of the MPc compounds and the properties of the molecular orbitals of the constituent molecules clearly indicates the richness of the alkali-doped metal-phthalocyanines as a model class of compounds for the investigation of the electronic properties of molecular systems.     

New matrix of MALDI-TOF MS for analysis of small molecules

New matrix, metal-phthalocyanine (MPc), of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used for analysis of small molecules (usually <500 Da). By using MPcs as matrices, small molecular samples were moved to high mass-to-charge region where there was no interference caused by the traditional matrices. The mass of the target analyte was obtained by simple calculation.     

A novel strategy for MALDI-TOF MS analysis of small molecules

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) does not work efficiently on small molecules (usually with molecular weight below 500 Da) because of the interference of matrix-related peaks in low m/z region. The previous methods developed for this problem focused on reducing the peaks caused by the traditional matrices. Here, we report a novel strategy to analyze small molecules in a high and interference-free mass range by using metal-phthalocyanines (MPcs) as matrices which should be capable of forming matrix-analyte adducts. The mass of the target analyte was calculated by subtracting the mass of MPc from the mass of the MPc-analyte adduct. MPcs were also detectable and could serve as internal standards. Various MPcs with aromatic or aliphatic groups and different metal centers were then synthesized and explored. Aluminum-phthalocyanines (AlPcs), gallium-phthalocyanines (GaPcs), and indium-phthalocyanines (InPcs) were efficient matrices to form MPc-analyte adducts in either the positive or negative ion mode. The detection limits varied from 17 to 75 fmol, depending on analyte types. The mechanism of adducts formation was also proposed. Collectively, our strategy provides a novel and efficient way to analyze small molecules by MALDI-TOF MS.     

Electropolymerization of Metallophthalocyanines Carrying Redox Active Metal Centers and their Electrochemical Pesticide Sensing Application

In this study, modified electrodes were constructed with the electropolymerization of metallophthalocyanines (MPcs) carrying redox active metal cations and electropolymerizable substituents. Then these electrodes were tested as selective and sensitive electrochemical pesticide sensors. Incorporation of the redox active Co(II) (CoPc(MOR‐NAF)), Cl–Mn(III) (MnPc(MOR‐NAF)), and Ti(IV)O (TiOPc(MOR‐NAF)) metal cations into Pc cavity increased the redox activity of Pc ring. Moreover, redox active and electropolymerizable 5‐{[(1E)‐(4‐morpholin‐4‐ylphenyl)methylene]amino}‐1‐naphthoxy substituents (MOR‐NAF) on the Pc ring triggered coating of the complexes on the electrode surface with the electropolymerization reactions. Therefore, modified electrodes GCE/MPc(MOR‐NAF) were constructed with the electropolymerizations of MPcs. These electrodes illustrated reasonable redox activity and conductivity for the potential applications in different fields of the electrochemical technologies. Pesticide sensing measurements indicated that changing the metal center of the complexes significantly altered their sensing activities. Among the complexes, GCE/CoPc(MOR‐NAF) electrode behaved as the most sensitive and selective electrode and it sensed the parathion with good selectivity and sensitivity. GCE/CoPc(MOR‐NAF) electrode showed a wider linear range (0.075‐5.75 μmoldm⁻³) and smaller LOD (0.025 μmoldm⁻³) and higher sensitivity (3.46 Acm⁻²M⁻¹) for the parathion sensing. Although GCE/TiOPc(MOR‐NAF) electrode also sensed the parathion with a high sensitivity, its selectivity was poor and the linear range of this sensing was very narrow. Differently GCE/Cl–MnPc(MOR‐NAF) electrode only sensed eserine with reasonably sensitivity.     

金属酞菁配合物的从头计算研究

利用从头计算方法研究了6种金属酞菁MPc(M=Zn2+、Cu2 +、Ni2+、Co2+、Fe2+、Mn2+)。得到了它们的基态能量,基态自旋多重度,分子轨道组成与能级,电荷分布与键序。其中,自旋多重度的计算结果与实验相符。中心离子d轨道参与HOMO、LUMO构成的程度可以解释各MPc光敏活性不同的实验现象。     

聚(金属酞菁)酰亚胺/碳纳米管复合材料的制备及介电性能

以四氨基铜(锌)酞菁为四胺单体, 与4,4'-二苯醚二胺(4,4'-ODA)和二苯醚四酸酐(ODPA)进行共聚, 合成了聚(金属酞菁)酰亚胺. 由于金属酞菁的引入, 聚(铜酞菁)酰亚胺和聚(锌酞菁)酰亚胺的介电常数均高于传统聚酰亚胺(PI). 以聚(铜酞菁)酰亚胺为基体, 采用溶液共混的方法, 制备了一系列碳纳米管/聚(铜酞菁)酰亚胺复合材料, 碳纳米管较为均匀地分散在聚合物基体中. 复合材料具有良好的介电性能, 掺杂碳纳米管质量分数为20%的复合材料的介电常数达到200, 介电损耗为2.25.     

Synthesis, characterization and nonlinear absorption of novel octakis-POSS substituted metallophthalocyanines and strong optical limiting property of CuPc

In this study, the preparation of some novel metallophthalocyanine (MPcs) complexes substituted with octakis(mercaptopropylisobutyl-POSS) functional group was achieved. By the reaction of [1-(3-mercapto)propyl-3,5,7,9,11,13,15-isobutylpentacyclo[9.5.1.1(3,9).1(5,15).1(7,13)]octasiloxane 1 with 4,5-dichloro-1,2-dicyanobenzene 2 in THF as the solvent in the presence of K2CO3 as the base, the phthalonitrile derivative 3 was synthesized. Compound 3 reacted with CoCl2 x 6H2O in ethylene glycol to furnish a novel cobalt(II) phthalocyanine . The tetramerization of 3 with urea and CuCl in the absence of solvent gave the novel Cu(II) phthalocyanine 4; while with Zn(OAc)2 x 2H2O in dry DMF gave the novel zinc(ii) phthalocyanine 6. The structures of the target compounds were confirmed by elemental analysis, UV/VIS, IR, MALDI-TOF MS and 1H NMR spectra. Nonlinear absorptions of MPcs in chloroform solution were investigated by using Z-scan measurement technique with 4 ns pulses at 532 nm wavelength. While CuPc 5 showed very high nonlinear absorption, MPcs 4 and 6 did not show considerable nonlinear absorption. Investigations of optical limiting properties of 5 revealed that this material is a very good candidate for optical limiting applications.     

硅胶键联MPc的制备及其在氧活化中的作用

过渡金属酞等配合物（MPC）用手均相液相氧化中作催化剂已有不少报导，象许多均相催化剂一样，MPC用于均相反应存在着难于从反应体系中分离出来的问题．把均相配合物催化剂固载在无机氧化物如硅股或有机高分子载体上是解决这一问题的一种方法．我们曾尝试把MP。固载在分子筛载体和硅胶载体上，并用ESR研究其对O2的活化作用[1，2]．本文报导MPc通过共价键键联固载在SiO2上，并研究其对O2的活化作用．1实验部分1．1试剂HSIC13为日本东京化成株式会社产品，二级试剂·发烟硫酸（SO。质量分数大于20％）为分析纯试剂．PCl5为化学纯试…     

Structure, vibrations and Raman modes in electron doped metal phthalocyanines

Identifying and understanding the vibrational frequency shifts caused by electron addition to metal phthalocyanine (MPc) molecules is the main goal of the present work. Among other things, it should be useful in establishing the amount of charge-transfer level recently reported in potassium doped solid MPc films. Choosing MgPc as our working case, we calculated by density functional methods the full vibration spectrum of the neutral and of the negatively charged molecule, with and without Jahn-Teller distortion. In the negative ion MgPc- we found that although individual modes behave differently, the generality of modes undergoes a negative frequency shift of about 10 cm(-1) for a single extra electron added in the eg affinity level. We calculated the Raman intensities and made qualitative connection with recent data on K-doped CuPc films. The detailed features and parameters of the static Jahn-Teller effect in a phthalocyanine molecular ion are obtained as a byproduct.     

Selective detection of vapor phase hydrogen peroxide with phthalocyanine chemiresistors

The use of hydrogen peroxide as a precursor to improvised explosives has made its detection a topic of critical importance. Chemiresistor arrays comprised of 50 nm thick films of metallophthalocyanines (MPcs) are redox selective vapor sensors of hydrogen peroxide. Hydrogen peroxide is shown to decrease currents in cobalt phthalocyanine sensors while it increases currents in nickel, copper, and metal-free phthalocyanine sensors; oxidation and reduction of hydrogen peroxide via catalysis at the phthalocyanine surface are consistent with the pattern of sensor responses. This represents the first example of MPc vapor sensors being oxidized and reduced by the same analyte by varying the metal center. Consequently, differential analysis by redox contrast with catalytic amplification using a small array of sensors may be used to uniquely identify peroxide vapors. Metallophthalocyanine chemiresistors represent an improvement over existing peroxide vapor detection technologies in durability and selectivity in a greatly decreased package size.     

The effect of protonation on the spectra and stabilities of alkoxyl substituted phthalocyaninatometals

The protonation abilities of phthalocyaninatometals (MPcs) increase but their stabilities reduce by the introduction of alkoxyl substituents at alpha position. In the toluene, the order of mono-protonation rate for the tetra-alpha-(2, 2, 4-trimethyl-3-pentoxy)phthalocyaninatometals sorts with the center metals is Zn>Co>Cu>Ni>Fe, which is opposite to the order of their wavelength difference between the Q bands and X bands. However, their mono-protonated species can be decomposed easily at the rate order FePc>CoPc>CuPc>NiPc>ZnPc, analogous to their decomposition abilities in the benzoylperoxide (BPO) oxidation. In addition, it is interesting that a more remarkable decomposition is found when partial CuPc was mono-protonated.     

In situ synthesis of metallophthalocyanines into pores of MIL‐101: A novel and green strategy for preparation of host–guest catalysts

A novel strategy is developed to encapsulate metallophthalocyanines (MPcs, M = Cu, Ni and Co) into MIL‐101 to give MPcs@MIL‐101 via in situ synthesis of MPcs from component fragments in 1‐butyl‐3‐methylimidazolium bromide as an ionic liquid. This strategy overcomes some drawbacks of existing methods for encapsulation of MPcs into metal–organic frameworks. The chemical and structural properties of MPcs@MIL‐101 were determined using scanning electron microscopy, powder X‐ray diffraction, and Fourier transformation infrared and flame atomic absorption spectroscopies. The results showed that CuPc@MIL‐101, which was used as a ‘ship‐in‐a‐bottle’ catalyst, demonstrates excellent catalytic performance in the oxidative amidation of aldehydes with amine salts. It is confirmed that CuPc@MIL‐101 can be reused up to five times without significant loss of its activity.     

Metallophthalocyanine‐Based Conjugated Microporous Polymers as Highly Efficient Photosensitizers for Singlet Oxygen Generation

Singlet oxygen (¹O₂) is of great interest because of its potential applications in photodynamic therapy, photooxidation of toxic molecules, and photochemical synthesis. Herein, we report novel metallophthalocyanine (MPc) based conjugated microporous polymers (MPc‐CMPs) as photosensitizers for the generation of ¹O₂. The rigid microporous structure efficiently improves the exposure of the majority of the MPc units to oxygen. The MPc‐CMPs also exhibit an enhanced light‐harvesting capability in the far‐red region through their extended π‐conjugation systems. Their microporous structure and excellent absorption capability for long‐wavelength photons result in the MPc‐CMPs showing high efficiency for ¹O₂ generation upon irradiation with 700 nm light, as evident by using 1,3‐diphenylisobenzofuran as an ¹O₂ trap. These results indicate that MPc‐CMPs can be considered as promising photosensitizers for the generation of ¹O₂.     

Synthesis,Characterization, Novel Interaction of DNA,Antioxidant and Antimicrobial Studies of New Water Soluble Metallophthalocyanines Posture Eight Hydroxyphenyl Moiety via 1,3,4‐oxadiazole Bridge

The new peripheral 2(3),9(10),16(17),23(24)‐tetra‐5‐[4,4′‐diphenol]‐phenyl‐[1,3,4]‐oxadiazole substituted metallophthalocyanine (MPc) complexes has been well designed and executed. Due to high conjugation and excellent solubility in water makes them potential use in DNA binding and cleavage studies. Fourier transform infrared spectroscopy, nuclear magnetic resonance, electron spin ionization mass spectra data, and elemental analysis confirmed the well‐defined saddle‐like distorted structures for these substituted MPc complexes. The successful synthesis of these novel water soluble MPc moieties were employed as an effective DNA binding with calf thymus DNA was monitored using ultraviolet?visible spectral titrations and cleavage pBR322 DNA conceded in the absence of reductant by agarose gel electrophoresis method. The results indicate that all these water soluble complexes significantly show excellent binding and modest cleavage sensitivity activity. It is noteworthy that 6 and 7 exhibit potential antimicrobial and appreciable antioxidant activity with other water soluble phthalocyanines.     

Graphene wrapped phthalocyanine: Enhanced oxidative desulfurization for dibenzothiophene in fuel

Graphene wrapped metal phthalocyanine (MPc/RGO, M = Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺) composites are synthesized by a facile ‘in situ hydrothermal’ method, using graphene oxide, M (CH₃COO)₂ and phthalic anhydride as the precursors. A biomimetic catalytic system of MPc/RGO and molecular O₂ have high activity for ultra‐deep removal of dibenzothiophene (DBT) in model oil containing n‐octane. Compared with pure graphene oxide and MPc, MPc/RGO composites displayed highly enhanced catalytic activity for the oxidation of dibenzothiophene in n‐octane. The conversion ratio of DBT was up to 97.51% after 180 min treatment at 60 °C and atmospheric pressure. The photostability of RGO/MPc composites photocatalystic degradation of dibenzothiophene was investigated. Mechanistic studies revealed that the RGO/MPc ? O₂ · species were the main active intermediate via the π‐π stacking interaction of MPc and RGO. The RGO wrapped phthalocyanine materials offer great potential as active photocatalysts for degradation of thiophene derivatives in fuel.