Analysis of traces of polycyclic aromatic hydrocarbons by adsorption on cobalt phthalocyanine and barium salts of sulphophthalocyanines followed by thermal desorption gas chromatograph

Small amounts of polycyclic aromatic hydrocarbons (PAHs) in aqueous solution were almost completely adsorbed on barium salts of copper (II) sulphophthalocyanines and cobalt (II) phthalocyanine, which were precipitated from the solution. Recoveries of the PAHs from the precipitates by thermal desorption gas chromatography were 71–95%. The method is useful for the concentration and analysis of medium molecular weight, thermally stable PAHs.     

Anthracene Substituted Co (II) and Cu (II) phthalocyanines; Preparations,Investigation of Catalytical and Electrochemical Behaviors

An approach to investigation of catalytical behaviors of Co (II) and Cu (II) phthalocyanines is reported that is based on changing any parameter to effect these behaviors. Towards this end, new anthracene substituted Co (II) and Cu (II) phthalocyanines were prepared and characterized spectroscopic methods. New cobalt (II) and copper (II) phthalocyanines were used as catalyst for oxidation of different phenolic compounds (such as 2,3‐dichlorophenol, 4‐methoxyphenol, 4‐nitrophenol, 2,3,6‐trimethylphenol) with different oxidants. Then, electrochemical characterization of cobalt (II) and copper (II) phthallocyanines were determined by using cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques. Although copper (II) phthalocyanine showed similar Pc based electron transfer processes, cobalt (II) phthalocyanine showed metal and ligand based reduction reactions as expected.     

Sensitive method for the determination of nitrated polycyclic aromatic hydrocarbons in the human diet

The presence of nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) as contaminants in foods is nowadays a legitimate cause of concern, as they are reported to be strong direct-acting mutagens and carcinogens that may pose a risk to human health. Nevertheless, their concentrations in foods are in the ultra-trace region. In this study, we present a very sensitive analytical method for the determination of this compound class in complex food matrices. Special emphasis was put on sample extraction and clean up. Recoveries of 75% could be obtained for 1- and 2-nitronaphthalene; for all other compounds investigated the recoveries were >/=94%. The determination of the compounds was performed by gas chromatography-mass spectrometry. The results show that the use of negative chemical ionization (NCI) increases the sensitivity by one order of magnitude in comparison to electron impact ionization (EI) (limits of detection 0.07-0.25 micro g kg(-1) for EI and 0.01-0.02 micro g kg(-1) for NCI). The influence of the sample matrix on the sensitivity of the method is demonstrated with extracts of a sample from a duplicate diet study. Due to the lack of a certified reference material the suitability of the method is demonstrated with pumpkin seed oil that was spiked with nitro-PAHs at two different concentration levels.     

Weak epitaxy growth and phase behavior of planar phthalocyanines on p-sexiphenyl monolayer film

We systematically investigated the weak epitaxy growth (WEG) behavior of a series of planar phthalocyanine compounds (MPc), i.e., metal-free phthalocyanine (H2Pc), nickel phthalocyanine (NiPc), copper phthalocyanine (CuPc), zinc phthalocyanine (ZnPc), iron phthalocyanine (FePc), cobalt phthalocyanine (CoPc), grown on a p-sexiphenyl ( p-6P) monolayer film by selected area electron diffraction (SAED) and atomic force microscopy (AFM). Two types of epitaxial relations, named as incommensurate epitaxy and commensurate epitaxy, were identified between phthalocyanine compounds and the substrate of the p-6P film. The tiny variation of the lattice constant of phthalocyanine compounds can result in different crystal orientations. The change rule of incommensurate and commensurate epitaxy was extracted. The tendency of commensurate epitaxy becomes weaker as the lattice constant b increases, while it gets stronger as the substrate temperature is elevated. Large size and continuous H2Pc films can be obtained by controlling the growth conditions. The WEG method is generally applicable in the whole family of planar phthalocyanine compounds and may be used to fabricate other high-quality organic films.     

Mixed indicators of methyl red with sulfonated phthalocyanines

Summary The applicability of sulfonated phthalocyanines as the dye constituents of mixed indicators with methyl red is investigated.Copper, cobalt and magnesium phthalocyanine sulfonates have been tried for this purpose and found to give very sharp color changes that can be observed in faded and artifical light as well.Copper phthalocyanine sulfonate is especially recommended for this purpose on account of its easy availability on the market. A mixture containing 2 parts by weight of methyl red sodium salt and 3 parts of the commercial copper phthalocyanine sulfonate is suggested as a useful mixed indicator in all acid-base titrations where methyl red is used.     

易溶性铜酞菁磺酸酯的合成及其凝聚性能

将酞菁氯磺化,然后与含有羟基的化合物反应,合成了铜酞菁磺酸苯酯、铜酞菁磺酸邻甲基苯酯、铜酞菁磺酸萘酯和铜酞菁磺酸 4 乙基萘酯,并测定了产物在不同溶剂中的溶解度、凝聚性能及红外光谱.这类铜酞菁衍生物的酯溶性很好.     

Synthesis and electrochemical properties of phthalocyanines with four 8-quinolinoxy-substituents

A metal-free phthalocyanine and its cobalt(II) and copper(II) phthalocyanate complexes were prepared by cyclotetramerization of 4-(8-quinolinoxy)phthalonitrile. The new compounds were characterized by elemental analyses, ¹H-n.m.r., i.r. and u.v.–vis. spectral data. Electrochemical measurements indicated that CoPc had two metal based and two ligand based redox couples, while H₂Pc and CuPc showed four ligand based redox couples. For all complexes, linear variation of the peak current of the first reduction peak (I _pc) with scan rate () indicated the adsorption of the complexes to the electrode surface.     

The effects of adsorption of solutes on glassware and teflon in the calculation of partition coefficients for solid-phase microextraction with 1PS paper

Solid-phase microextraction presents numerous advantages over traditional extraction techniques. However, the determination of partition coefficients is not as simple as it may appear. For very nonpolar compounds, such as polycyclic aromatic compounds, adsorption to the glass wall of the extraction vial and the Teflon coating of the stir bar may be quite significant. These interactions must be taken into account when calculating partition coefficients. Failing to do this may lead to large errors in the value of the partition coefficient, particularly for very nonpolar compounds. Three polar compounds and seven polycyclic aromatic hydrocarbons were partitioned individually between Whatman 1PS paper and water solutions of the compounds. The partition coefficiencts were calculated with two equations, and detailed mass balance data were acquired for the adsorption of the solute on the stir bar, glass vial, and 1PS paper. The mass data were compared with the partition coefficients, and important conclusions were made about the practical use of the partition coefficients.     

Theory and application of dissociative electron capture in molecular identification

The coupling of an electron monochromator (EM) to a mass spectrometer (MS) has created a new analytical technique, EM-MS, for the investigation of electrophilic compounds. This method provides a powerful tool for molecular identification of compounds contained in complex matrices, such as environmental samples. In particular, EM-MS has been applied to the detection of nitrated aromatic compounds, many of which are potent mutagens and/or carcinogens and are considered environmental hazards. EM-MS expands the application and selectivity of traditional MS through the inclusion of a new dimension in the space of molecular characteristics-the electron resonance energy spectrum. EM-MS also enhances detection sensitivity as well because the entire electron flux of the proper energy can be delivered into the negative ion resonance that is analytically most useful to solving the problem at hand. However, before this tool can realize its full potential, it will be necessary to create a library of resonance energy scans from standards of the molecules for which EM-MS offers a practical means of detection. Unfortunately, the number of such standards is very large and not all of the compounds are commercially available, making this library difficult to construct. Here, an approach supplementing direct measurement with chemical inference and quantum scattering theory is presented to demonstrate the feasibility of directly calculating resonance energy spectra. This approach makes use of the symmetry of the transition-matrix element of the captured electron to discriminate between the spectra of isomers. As a way of validating this approach, the resonance values for 25 nitrated aromatic compounds were measured along with their relative abundance. Subsequently, the spectra for the isomers of nitrotoluene were shown to be consistent with the symmetry-based model. The initial success of this treatment suggests that it might be possible to predict negative ion resonances and thus create a library of EM-MS standards.     

Structure–activity relationship models for rat carcinogenesis and assessing the role mutagens play in model predictivity

We previously demonstrated that fragment based cat-SAR carcinogenesis models consisting solely of mutagenic or non-mutagenic carcinogens varied greatly in terms of their predictive accuracy. This led us to investigate how well the rat cancer cat-SAR model predicted mutagens and non-mutagens in their learning set. Four rat cancer cat-SAR models were developed: Complete Rat, Transgender Rat, Male Rat and Female Rat, with leave-one-out (LOO) validation concordance values of 69%, 74%, 67% and 73%, respectively. The mutagenic carcinogens produced concordance values in the range 69–76% compared with only 47–53% for non-mutagenic carcinogens. As a surrogate for mutagenicity, comparisons between single site and multiple site carcinogen SAR models were analysed. The LOO concordance values for models consisting of 1-site, 2-site and 4+-site carcinogens were 66%, 71% and 79%, respectively. As expected, the proportion of mutagens to non-mutagens also increased, rising from 54% for 1-site to 80% for 4+-site carcinogens. This study demonstrates that mutagenic chemicals, in both SAR learning sets and test sets, are influential in assessing model accuracy. This suggests that SAR models for carcinogens may require a two-step process in which mutagenicity is first determined before carcinogenicity can be accurately predicted.     

The adsorption of monomers (metal complexes with Schiff bases) and the structure and properties of polymeric films formed on the surface of graphite

The adsorption of nickel(II) and copper(II) complexes with the N,N′-ethylenebis(salicylideneimine) ligand on carbonaceous materials and at the air-solution boundary was studied. A correlation was observed between adsorption parameters and the structure of polymeric films formed as a result of the electrode oxidation of these compounds (monomers).     

Selective metal sensor phthalocyanines bearing non-peripheral functionalities: Synthesis,spectroscopy, electrochemistry and spectroelectrochemistry

A novel alcohol-soluble ionophore ligand and its non-peripherally tetrasubstituted functional 1,8,15,22-tetrakis(6-hydroxyhexylsulfanyl) metallophthalocyanines M[Pc(α-SC₆H₁₂OH)₄] (M = Cu(II), Zn(II), Co(II); Pc = phthalocyanine) are reported. The aggregation and cation binding behaviors of the phthalocyanine compounds in the presence of soft Ag^I and Pd^II metal ions were investigated by using UV–Vis spectroscopy. The new compounds have been characterized by elemental analysis, IR, ¹H, ¹³C NMR, UV/Vis spectroscopy, ESI and MALDI–TOF–MS mass spectra. Voltammetric and in-situ spectroelectrochemical studies show that while copper and zinc phthalocyanine complexes give well-defined ring-based reduction and oxidation processes, the cobalt phthalocyanine gives both metal-based and ring-based redox processes which have reversible and diffusion controlled character.     

Advanced Methodologies for Adsorption/Thermal Desorption with Tenax-TA for the Analysis of Polycyclic Aromatic Hydrocarbons and Sulfur Compounds

We have evaluated an analytical method for the determination of polycyclic aromatic hydrocarbons (PAHs) and sulfur compounds in air by means of adsorption/temperature-programmed thermal desorption (ATPTD) with small bed volume (0.08g) Tenax-TA cartridges, followed by a cryogenic trap in a precolumn with liquid nitrogen as an appropriate concentration method before capillary gas chromatography is described. The enriched components from the adsorption cartridges are transferred to the capillary column with a valveless switching system. Recoveries were determined for the complete ATPTD method. Desorption recoveries near 100% were found for various of polycyclic aromatic hydrocarbons and sulfur compounds. The sulfur compounds known to cause nuisance odors in the atmosphere near sulfur recovery and sewerage treatment works were also determined.     

Experimental and theoretical insights into copper phthalocyanine-based covalent organic frameworks for highly efficient radioactive iodine capture

Exploring efficient materials for capturing radioactive iodine in nuclear waste is of great significance for the progress of nuclear energy as well as the protection of ecological environment. Covalent organic frameworks (COFs) have emerged as promising adsorbents because of their predesignable and functionalizable skeleton structures. However, it remains a grand challenge to achieve large scale preparation of COFs. In this work, we developed a mild and efficient microwave irradiation method instead of the traditional solvothermal method to prepare copper phthalocyanine-based covalent organic frameworks (Cu_xPc-COFs) within only 15 min. The nitrogen-rich 1,2,4,5-tetracarbonitrilebenzene (TCNB) was selected as the solely organic ligand to construct copper phthalocyanine-based 2D conjugated COFs. The resultant Cu_xPc-COFs exhibited excellent iodine enrichment with 2.99 g/g for volatile iodine and 492.27 mg/g for iodine-cyclohexane solution, respectively, outperforming that of many porous materials. As indicated by spectroscopic analysis and DFT calculations, this impressive adsorption performance can be attributed to the charge transfer arising from nitrogen-rich phthalocyanine structures and electron-rich π-conjugated systems with iodine molecules. Moreover, the strong electrostatic interaction between Cu(II) on chelate centers and polyiodide anions (I_x^?) also play an important role in the firmly trapping radioactive iodine. Therefore, this study provides a facile and intelligent approach to implement metal-based COFs for the remediation of toxic radioactive iodine.     

Influence of silicon defects on the adsorption of thiophene-like compounds on polycyclic aromatic hydrocarbons: a theoretical study using thiophene + coronene as the simplest model

Physisorption and chemisorption processes of thiophene on coronene and 2Si-coronene have been studied using density functional theory and MP2 methods. These systems have been chosen as the simplest models to describe the adsorption of thiophene-like compounds on polycyclic aromatic hydrocarbons (PAHs). The calculated data suggest that the presence of silicon atoms in PAHs could favor their interaction with thiophene and similar compounds. Small stabilization energies have been found for several physisorbed complexes. The thiophene chemisorption on coronene seems very unlikely to occur, while that on 2Si-coronene leads to addition products which are very stable, with respect to the isolated reactants. These chemisorption processes were found to be exoergic (DeltaG < 0) in the gas phase and in the nonpolar liquid phase. The results reported in this work suggest that silicon defects on extended polycyclic aromatic hydrocarbons, such as graphite, soot, and large-diameter carbon nanotubes, could make them useful in the removal processes of aromatic sulfur compounds from oil hydrocarbons.     

Synthesis,electrochemistry and in situ spectroelectrochemistry of water-soluble phthalocyanines

The synthesis, characterization and voltammetric and spectroelectrochemical properties of newly synthesized metal-free and metallo phthalocyanines (M = Co, Cu, Zn) containing four dialkylaminophenoxy or trialkylammoniumphenoxy substituents on peripheral positions have been presented in this work. The new compounds have been characterized by using elemental analysis, UV–Vis, FT-IR, ¹H NMR and MS spectroscopic data. Phthalocyanines with trialkylammoniumphenoxy substituents are soluble in aqueous solution over a wide pH range, and these compounds are present as aggregated species in solution as confirmed by the blue shift of Q-bands in their electronic spectra. The electrochemical behavior of the phthalocyanines was investigated by cyclic voltammetry and differential pulse voltammetry on a platinum-working electrode in DCM and DMSO. The voltammetric and spectroelectrochemical measurements of the complexes show that while cobalt phthalocyanine gives both ligand- and metal-based redox processes, metal-free, zinc and copper phthalocyanine complexes give only ligand-based processes in harmony with common phthalocyanine complexes.     

Sequential amination/annulation/aromatization reaction of carbonyl compounds and propargylamine: a new one-pot approach to functionalized pyridines

A general one-pot synthesis of pyridines 4a-t from the reaction of dialkyl acyclic/cyclic ketones 1a-i, methyl, aryl/heteroaryl ketones 1m-r, and aldehydes bearing alpha-hydrogens 1s,t with propargylamine 2 is described. Gold and copper salts are efficient catalysts for the reaction of ketones with 2. The formation of the pyridines 4 is suggested to proceed through the sequential amination of carbonyl compounds followed by regioselective 6-endo-dig cyclization of the N-propargylenamine (N-propargyldienamine) intermediate 3(5) and aromatization reaction. Whereas the preparation of linear polycyclic pyridine 4i can be carried out by reacting cholestan-3-one 1i with 2, the angular polycyclic pyridine 4j has been obtained starting from cholest-5-en-3-one 1j. Selectivity of the reaction of polycyclic dicarbonyls 1k,l with 2 has also been investigated.     

Tetra-t-butyl magnesium phthalocyanine on gold: electronic structure and molecular orientation

In this work we have investigated the electronic structure and the molecular orientation of (t-Bu)(4)PcMg (tetra-t-butyl magnesium phthalocyanine) on polycrystalline and single crystalline gold substrates using photoemission spectroscopy and x-ray absorption spectroscopy, and we compare the results to the unsubstituted PcCu (copper phthalocyanine). The C 1s photoemission spectrum is described similar to unsubstituted relatives with an additional component for the aliphatic substituents. The variation of the excitation energy causes distinct differences in the shape of the C 1s spectrum, which is very useful for the analysis of the molecular orientation in the uppermost layer. It is shown that despite of the sterically demanding substituents, ordered sublimed films of (t-Bu)(4)PcMg are accessible, the orientation of the molecules, however, is different from the orientation of the unsubstituted relatives.     

Matrix effects on copper(II)phthalocyanine complexes. A combined continuous wave and pulse EPR and DFT study

The effect of the electron withdrawing or donating character of groups located at the periphery of the phthalocyanine ligand, as well as the influence of polar and nonpolar solvents are of importance for the redox chemistry of metal phthalocyanines. Continuous wave and pulse electron paramagnetic resonance and pulse electron nuclear double resonance spectroscopy at X- and Q-band are applied to investigate the electronic structure of the complexes Cu(II)phthalocyanine (CuPc), copper(II) 2,9,16,23-tetra-tert-butyl-29H,31H-phthalocyanine (CuPc(t)), and copper(II) 1,2,3,4,8,9,10,11,15,16,17,18,22,23,24,25-hexadecafluoro-29H,31H-phthalocyanine (CuPc(F)) in various matrices. Isotope substitutions are used to determine the g values, the copper hyperfine couplings and the hyperfine interactions with the 14N, 1H and 19F nuclei of the macrocycle and the surrounding matrix molecules. Simulations and interpretations of the spectra are shown and discussed, and a qualitative analysis of the data using previous theoretical models is given. Density functional computations facilitate the interpretation of the EPR parameters. The experimental g, copper and nitrogen hyperfine and nuclear quadrupole values are found to be sensitive to changes of the solvent and the structure of the macrocycle. To elucidate the electronic, structural and bonding properties the changes in the g principal values are related to data from UV/Vis spectroscopy and to density functional theory (DFT) computations. The analysis of the EPR data indicates that the in-plane metal-ligand sigma bonding is more covalent for CuPc(t) in toluene than in sulfuric acid. Furthermore, the out-of-plane pi bonding is found to be less covalent in the case of a polar sulfuric acid environment than with nonpolar toluene or H2Pc environment, whereby the covalency of this bonding is increased upon addition of tert-butyl groups. No contribution from in-plane pi bonding is found.     

Studies on thermal behavior of some antibacterial copper (II) complex compounds with a dibiguanide derivative ligand

The thermal behavior of six complex compounds of Cu(II) with chlorhexidine as ligand was investigated. The complexes are obtained from chlorhexidine diacetate and copper (II) chloride, bromide and acetate, respectively, in metal:ligand molar ratio 1:1 and 2:1. Thermal decomposition evidenced several well-defined steps as desolvation, anionic moieties release and the ligand cleavage for all complexes. The final residue is in all cases copper (II) oxide.