Perylene Research Articles

Application of ‘multivariate curve resolution alternating least square (MCR–ALS)’ analysis to extract pure component synchronous fluorescence spectra at various wavelength offsets from total synchronous fluorescence spectroscopy (TSFS) data set of dilute aqueous solutions of fluorophores

In the present study, the possibility of using the multivariate curve resolution alternating least square (MCR–ALS) analysis for the simultaneous extraction of the pure synchronous fluorescence spectra at various wavelength offsets (Δλ) for each fluorophore from the total synchronous fluorescence spectroscopy (TSFS) data set of the dilute aqueous mixtures of the three fluorophores, was explored. The present work was based on the assumption that unfolded TSFS data has a bilinear structure and therefore it can be subjected to MCR–ALS analysis. Three fluorophores, benzo[a]pyrene(BaP), perylene(PE), and pyrene(PY), were chosen. These three fluorophores show fluorescence at all the seven wavelength offsets (Δλ) used to create the TSFS data set. In addition, Raman scattering due to solvent molecules (i.e. water) also appear in the wavelength ranges where these fluorophores show fluorescence. These two factors make the simultaneous extraction of synchronous spectral profile at various Δλs from the TSFS data set relatively difficult. The appearance of the diagonal signals in the three‐dimensional landscapes of TSFS shows the presence of the Raman scattering. The Raman signal due to solvent molecules was found to influence the synchronous profile of a fluorophore to different extents at different Δλs. TSFS data set of dimension, sample×wavelength×Δλ, was unfolded along the first mode to obtain the unfolded TSFS data set. Pure synchronous spectral profiles at various Δλs were obtained for each fluorophore by performing the MCR–ALS analysis on the unfolded TSFS data. However Raman scattering signals could not be eliminated from the synchronous spectral profiles of the PE and PY. For the mitigation of Raman scattering from the calculated spectral profiles, TSFS data of solvent blank were subtracted from all the samples before performing the MCR–ALS analysis. The obtained spectral profiles of BaP, PE, and PY were found to match with their actual spectral profiles which verifies that unfolded TSFS data set has a bilinear structure. To test the strength of the present work, MCR–ALS analysis was also performed on the unfolded TSFS data set of 12 groundwater samples which were contaminated with the BaP‐ and PY‐spiked gasoline. The obtained results show that it is possible to monitor the presence of BaP and PY in groundwater samples.

Electrochemical and electrochromic properties of a novel copolymer based on perylene and EDOT

Copolymer of perylene (PE) with 3,4-ethylenedioxythiophene (EDOT) was electrochemically synthesized and characterized. The resultant copolymer film not only has orange-light emitter property, but also possesses distinct electrochromic properties. It shows four colors at different doped states (from red–brown to light-green). Double potential step chronoamperometry experiment reveals that the copolymer film has high optical contrast (25% at 516nm, 42% at 1100nm) and fast switching time (2s). Cyclic voltammograms indicate that the polymer has reasonable stability because of the existence of EDOT units.

Naphthalene production by microorganisms associated with termites: Evidence from a microcosm experiment

There have been several reports published which suggest that it is possible that the polycyclic aromatic hydrocarbons (PAHs) naphthalene (NAPH), phenanthrene (PHEN) and perylene (PERY) in tropical environments have a biological source. This source might be related to the activity of termites or their associated microorganisms. We aimed to provide direct evidence for the biological production of NAPH, PHEN and PERY by conducting microcosm experiments in the State of Tocantins, Brazil, in which termite nests (with or without termites) were placed in an enclosed environment in which we controlled all PAH fluxes and monitored changes of PAH stocks. The experiments were carried out with termites from a tropical floodplain forest environment at the Estação Canguçu (Ilha do Bananal) in the State of Tocantins, Brazil. We set up the following treatments: live nest of Nasutitermes cf. minor using PAH-poor wood as food (LNW), live nest of Nasutitermes cf. minor using PAH-poor corn as food (LNC), termite nest without live termites called dead nest (DNC) and dead nest with additional treatment by a combined fungicide/bactericide (FDN) in several replicates. In LNW, LNC, and DNC, there were mean increases of 43%, 21%, and 46% in NAPH stock after 20 d while the stocks of the 20 other PAHs studied did not change or even decreased. In contrast, FDN lost 20% of the NAPH stock after 20 d of the microcosm experiment because of dissipation and lack of microbial synthesis of new NAPH. In LNW and LNC, low-molecular weight PAHs (acenaphthylene to chrysene) were significantly lost at a mean percentage which was strongly correlated with the octanol–water partitioning coefficient ( K OW, r = 0.78). This was not the case in DNC and FDN. There were no indications that in the studied termite nests PHEN and PERY were produced. Our microcosm experiments suggest that NAPH can be produced by fungi and bacteria in termite mounds while all other low-molecular weight PAHs are degraded in microcosms with live termite nests. PAH degradation seems to be enhanced by the combined activity of termites and microorganisms.

Brightly shining nanoparticles

The dispersion of lipophilic perylene bisimides down to nanoparticle dimensions opens the aqueous phase to these highly fluorescent, water insoluble materials.

Human Aryl Hydrocarbon Receptor Ligand Activity of 31 Non-substituted Polycyclic Aromatic Hydrocarbons as Soil Contaminants

Toxic equivalency factors (TEFs) of 31 non-substituted polycyclic aromatic hydrocarbons (PAHs) for the human aryl hydrocarbon receptor (AhR) ligand activity were measured using the yeast recombinant reporter gene assay established by Miller et al., in order to estimate the toxic equivalents of individual PAHs in environmental samples. Ten PAHs showed sigmoid-shape concentration-response curves. An effective concentration to achieve 50% activity obtained with 1 μmol/l benzo[a]pyrene (BaP) (EC50BaP) was calculated by curve fitting, and TEFs were calculated from the ratio of EC50BaP for BaP to that for the chemical studied. The highest TEF was found for naphthacene (NPC) (TEF=35) followed by benzo[b]fluorene (BbFl) (19), benzo[k]fluoranthene (BkF) (11), benz[a]anthracene (BaA) (7.0), benzo[j]fluoranthene (BjF) (4.0), benzo[a]fluorene (BaFl) (1.9), benzo[b]fluoranthene (BbF) (1.4), chrysene (CHR) (1.1), and BaP (1.0). Concentration dependent activities were also observed for indeno[1,2,3-cd]pyrene (IP) and fluoranthene (FLT). The TEFs of IP and FLT were about 0.2 and 0.02, respectively. The other 19 PAHs, naphthalene (NPT), acenaphtylene (ACL), acenaphthene (ACT), fluorene (FLU), anthracene (ANT), phenanthrene (PHN), pyrene (PYR), triphenylene (TRI), benzo[e]pyrene (BeP), perylene (PER), benzo[ghi]perylene (BgP), dibenz[a, h]anthracene (DahA), picene (PIC), coronene (COR), dibenzo[a, e]pyrene (DaeP), dibenzo[a, h]pyrene (DahP), dibenzo[a, i]pyrene (DaiP), dibenzo[a, l]pyrene (DalP) and naphtho[2,3-a]pyrene (NaP), showed little or no activity in the 0.1-1,000 nmol/l range. The toxic equivalents (TEQs) of surface soil were calculated by multiplication of the TEFs with the concentrations in soil samples collected from Kyoto, Japan. The TEQ of BaA showed the highest value of the 16 US Environmental Protection Agency Priority Pollutant PAHs.

Alternative Normalization Method of Atmospheric Polycyclic Aromatic Hydrocarbons Pollution Level Recorded by Tree Bark

An alternative normalization method was developed for evaluating atmospheric polycyclic aromatic hydrocarbons (PAHs) pollution level when using tree bark as a passive sampling medium. Perylene (PER), which mainly stems from natural biogenic processes, was proposed as a "natural internal compound" (NIC) of atmospheric PAHs accumulation processes from air into the bark, and a concentration ratio of target PAH to PER (RPAH/PER) was used to minimize the uncertainty in the evaluation of atmospheric PAHs pollution level. Systematic investigation of the effects of intrinsic bark characteristics and extrinsic seasonal meteorological conditions on the partition processes of atmospheric PAHs indicated that RPAH/PER is as an alternative index as compared to bark mass concentration (BMCPAH, ng/g dry bark), lipid mass concentration (LMCPAH, ng/g lipid of bark), and area mass concentration (AMCPAH, ng/m2 surface area of bark) for the evaluation of atmospheric PAHs pollution and that it allows more flexible sampling of tree barks. Clearly, the methodology should be expected to be useful for the objective evaluation of atmospheric pollution levels of other persistent organic pollutants when using tree bark and other passive sampling media if corresponding NICs are found in the future.

Anisotropy of charge and spin motion in perylene hexafluoroarsenate salts

Conduction electron spin echo attenuation in well defined magnetic field gradients providesmore accurate values of the anisotropy of electron spin motion than microwave conductivitymeasurements. The electron spin diffusion coefficient for motion along the perylene (PE)radical cation stack, , in the PE hexafluoroarsenate salt is influenced temperature dependently byperpendicular-to-stack motion and reflects the varying average unrestricted chain length,. The anisotropy of is larger than 7300:1 at 250 K.

ANALYSIS OF POLYCYCLIC AROMATIC HYDROCARBON IN SOME MEAT PRODUCTS

The polycyclic aromatic hydrocarbons (PAHs) are a class of organic compounds, composed two or more fused aromatic (benzene) rings, occurred in the environment due to incomplete combustion of organic matters such as forest fires, volcanic eruption, burning of fossil fuels and incorrect process of meat cooking (grilling, smoking, roasting). Healt concerns are focussed on the metabolite transformation of PAHs, which may have mutagenic, carcinogenic and terratogenic activity. Due to their hydophobicity, it is probable the compounds enter human food chain and accumulated in human lipid tissues. Therefore, environment pollution by PAHs must be considered. PAHs gain entry to human body through several routes including respiration, absorpsion through skin surface ang through food consumption that have been polluted with PAHs. In this study concentrations of PAHs (pyrene, perilene, benzo(a)anthracene, benzo(k)fluorantrene and benzo(a)pyrene) in traditional smoked meat, liquid smoked meat and roasted meat are determined. Determination of PAHs used gas chromatograph with OV 17 2% as a stationary phase, nitrogen as carrier gas and flame ionization detector. The results showed that PAHs concentrations in traditional smoked meat were higher than liquid smoked meat (41.19 ppb and 1.03 – 9.26 ppb). In the roasted meat, lipid concentration and roasting time influence PAHs concentration level. Keywords : polycyclic aromatic hydrocarbon, smoked meat, liquid smoke

Atmospheric versus biological sources of polycyclic aromatic hydrocarbons (PAHs) in a tropical rain forest environment

To distinguish between pyrogenic and biological sources of PAHs in a tropical rain forest near Manaus, Brazil, we determined the concentrations of 21 PAHs in leaves, bark, twigs, and stem wood of forest trees, dead wood, mineral topsoil, litter layer, air, and Nasutitermes termite nest compartments. Naphthalene (NAPH) was the most abundant PAH with concentrations of 35 ng m −3 in air (>85% of the ∑21PAHs concentration), up to 1000 μg kg −1 in plants (>90%), 477 μg kg −1 in litter (>90%), 32 μg kg −1 in topsoil (>90%), and 160 μg kg −1 (>55%) in termite nests. In plants, the concentrations of PAHs in general decreased in the order leaves > bark > twigs > stem wood. The concentrations of most low-molecular weight PAHs in leaves and bark were near equilibrium with air, but those of NAPH were up to 50 times higher. Thus, the atmosphere seemed to be the major source of all PAHs in plants except for NAPH. Additionally, phenanthrene (PHEN) had elevated concentrations in bark and twigs of Vismia cayennensis trees (12–60 μg kg −1), which might have produced PHEN. In the mineral soil, perylene (PERY) was more abundant than in the litter layer, probably because of in situ biological production. Nasutitermes nests had the highest concentrations of most PAHs in exterior compartments (on average 8 and 15 μg kg −1 compared to <3 μg kg −1 in interior parts) and high PERY concentrations in all compartments (12–86 μg kg −1), indicating an in situ production of PERY in the nests. Our results demonstrate that the deposition of pyrolytic PAHs from the atmosphere controls the concentrations of most PAHs. However, the occurrence of NAPH, PHEN, and PERY in plants, termite nests, and soils at elevated concentrations supports the assumption of their biological origin.

Historical records of airborne polycyclic aromatic hydrocarbons by analyzing dated corks of the bark pocket in a Longpetiole Beech tree.

Historical monitoring of airborne polycyclic aromatic hydrocarbons (PAHs) pollution levels was novelly demonstrated by analyzing the dated corks of a bark pocket formed from 1873 to 2003 in a Longpetiole Beech (Fagus longipetiolata) tree trunk sampled from southeastern China. The fundamental studies indicated that the PAHs of log K(oa) < 8.5 are primarily accumulated through interactions with lipid substances in cork and log K(oa) dependent, while the PAHs of log K(oa) > 8.5 existing as particle-phase dependent on log Vp are accumulated through stochastic entrapment by the lenticels on the surface of the cork. The translocation of PAHs by xylem flow and phloem stream as well as radial diffusion from the cork to the inner tissues was not significant, and the cork is most effective for accumulating airborne PAHs. The total concentrations of 16 EPA PAHs (sumPAHs) in the dated corks progressively increased from 43.5 ng/g recorded in the earliest available cork in 1873-1875 to the maximum 345.7 ng/g in 1956-1961, and then gradually decreased to 267.0 ng/g in 2003, while the concentration of perylene (PER) was slightly fluctuating at 0.178 +/- 0.033 ng/g. Moreover, the concentration ratio of sumPAHs to PER increased from 193 to 2431 from 1873 to 2003, indicating a progressive increase in PAH pollution in southeastern China.

Nanostructured films of perylene derivatives: High performance materials for taste sensor applications

Nanostructured films of perylene derivatives: High performance materials for taste sensor applications

Electrochemiluminescence impedance of perylene in acetonitrile

The electrochemiluminescence (ECL) of perylene (PE) has been studied by the electrochemical measurements involving a new transfer function in the frequency domain. When the sufficient voltage is imposed between two platinum electrodes in acetonitrile containing PE, the cation radical PE + and anion radical PE − are formed on the anodic and cathodic electrodes, respectively, and the reaction of PE + with PE − emits the fluorescence. This luminescence was measured by a chemiluminescence detecter combined with the electrochemical cell for the flow injection analysis. The ECL impedance, which is the ratio of the luminescence amplitude to the current, was determined by the frequency response analyzer. The ECL impedance shows the frequency dispersion because the ECL has an induction period due to the diffusion process after the electrolysis. The ECL mechanism was discussed by comparing the experimental results of ECL impedance with the theoretical equations.

Polycyclic aromatic hydrocarbon (PAH) patterns in climatically different ecological zones of Brazil

Understanding the global distribution of PAHs requires knowledge of their sources. The objective of our work was to test the hypothesis that termites and woody plants are sources of naphthalene (NAPH), phenanthrene (PHEN), and perylene (PERY) for soils of different tropical climates. We determined the concentrations of 20 PAHs in soil, wood, and different compartments of termite nests (central part, inner wall, outer wall) in the Amazon (Terra firme, Várzea, and Igapó), Pantanal, Cerrado, Mata Atlântica, and Caatinga regions. The sum of 20 PAH concentrations was low in all soils (4.8–347 μg kg−1, n=47) and much higher in many of the wood (47–3894, n=31) and termite nest samples (29–4208, n=121). In general, NAPH, PHEN, or PERY were most abundant. In the Amazon region, wood samples contained up to 3785 and termite nest samples up to 3645 μg kg−1 of NAPH. In all regions, most termite nests contained higher PERY concentrations (up to 1109 μg kg−1) than wood or soil, indicating that PERY was produced or accumulated in these nests. In many termite nests, the central part had larger NAPH and PERY concentrations than the wall, indicating that these compounds may have been produced within the nests. With few exceptions, NAPH dominated the PAH pattern in the Amazon and west Cerrado regions, PHEN in the Mata Atlântica and Caatinga regions, and PERY in the Pantanal and central Cerrado regions. Our results suggest that there are large unknown sources of NAPH, PHEN, and PERY in the tropical environment. It is likely that part of these sources is biological. The release of NAPH and PHEN from these sources seems to depend on climatic factors.

Synthesis of organic one-dimensional nanomaterials by solid-phase reaction.

The synthesis of anthracene (AN) nanowires and perylene (PY) nanorods on the basis of solid-phase organic reactions under controlled conditions is discussed, and the structures are confirmed by SEM, TEM, and XRD. The dimension-dependent emission properties of the AN nanowires and PY nanorods is observed. This approach is expected to form a new general route for the controlled morphosynthesis of organic molecular materials in restricted dimensions, with controlled size and shape, the solid-state physical properties of which are of great interest. It should have outstanding potential in providing customized 1D nanomaterials for a broad range of applications for molecule devices and nanoscience and is expected to be applicable other functionalized nanomaterials (i.e., organic, inorganic, and polymer).

Dependence of electron transfer dynamics in wire-like bridge molecules on donor–bridge energetics and electronic interactions

Electron transfer (ET) reactions in donor–bridge–acceptor (DBA) molecules that occur by means of superexchange interactions between the donor (D) and the bridge (B) molecules depend on the vertical energy gap separating D and B. This dependence modulates the electronic coupling matrix element for ET, and hence the ET rate. However, when the energy gap between D and B is small, the assumptions intrinsic to the simplest superexchange model break down and charge injection from D to B may occur. To investigate this range of possibilities, we synthesized a family of DBA molecules based on a 2,5-bis(2 ′-ethylhexyloxy)-1,4-distyrylbenzene (OPV3) bridge. Three electron donors, zinc 5,10,15,20-tetraphenylporphyrin (ZnTPP), perylene (PER) and tetracene (TET) as well as two electron acceptors naphthalene-1,8:4,5-bis(dicarboximide) (NI) and pyromellitimide (PI) were attached to the OPV3 bridge. The observed ET dynamics of these molecules are sensitive not only to the donor–bridge energy gap, but also to the excited state torsional dynamics between the donor and bridge.

Coexistence of neutral and charged arenes in conducting diperylene hexafluorophosphate

In the quasi-one-dimensional organic conductor diperylene hexafluorophosphate charged and neutral perylene (PE) molecules coexist. The molecular charge can be correlated with the distance between the PE molecule's two naphthalene moieties accessible by x-ray structural analysis. The electronic distinction is proved by magic angle sample-spinning proton-enhanced high-resolution ${}^{13}\mathrm{C}$ nuclear magnetic resonance. The locally resolved ${}^{13}\mathrm{C}$-shift data in addition reveal the occurrence of two inequivalent PE molecules in the conducting stack of diperylene hexafluorophosphate.

Distribution of perylene and five‐ring polycyclic aromatic hydrocarbons in sediment and airborne particulate matter

Characteristic distribution of perylene (PER) in river sediment was compared with those of three anthropogenically derived polycyclic aromatic hydrocarbons (PAHs) with five‐rings, benzo[a]pyrene (B[a]P), benzo[b]fluoranthene (B[b]F) and benzo[k]fluoranthene (B[k]F) as well as the four PAHs in airborne paniculate matter (APM). Concentrations of the four PAHs in APM were strongly correlated with each other, and the PAH ratios to B[a]P in APM showed no statistically significant difference in the investigated sites. Concentrations of B[a]P, B[b]F and B[k]F in sediment were strongly correlated with each other, whereas PER in sediment showed relatively lower correlations. The relative PER ratio to B[a]P in sediment decreased significantly with increase of B[a]P concentration. PER in sediment seems to be originated both from the anthropogenic and natural sources; mean of anthropogenic PER ratio in sediment was estimated as 20% in arithmetic or 7.8% in geometric.

Spin and charge distribution in hexaperylene hexafluorophosphate, (C 20H 12) 6PF 6

The 6:1 radical cation salt of perylene (PE) and hexafluorophosphate is an organic semiconductor with one unpaired electron spin per formula unit. The crystal structure consists of three nearly orthogonal (PE) dimers, which are grouped around the PF 6 − anion. Anisotropy and temperature dependence of the g tensor and linewidth of the electron spin resonance (ESR) at 9.5 GHz were studied, in order to determine the origin of the observed ESR line narrowing and the distribution of the radical spin density over the different PE molecules within the unit cell of (PE) 6PF 6.

The Peierls transition of Perylene radical cation salts with 2:1 stoichiometry containing tetrahydrofuran

Crystal structure, microwave conductivity and static magnetic susceptibility were analyzed for the conducting perylene (PE) radical cation salts of nominal composition (PE)2(PF6)1−x(AsF6) x ·2/3 THF for 0≦x≦1. Crystallographic phase transitions in the high-temperature metal phase were also characterized by differential scanning calorimetry and electron spin resonance. The Peierls transition occuring at 100–120 K (depending onx) and the opening of the energy gap in the semiconductor phase were determined from the magnetic data. The dependence of these properties on the size of the complex anions and the packing of the PE molecules is discussed.

Peierls transition of perylene radical cation salts with five-eighth filled conduction band

The Peierls transition of Perylene (PE) radical cation salts ( PE) 2X 1 · 2 3 THF (nominal composition, X = (PF 6) 1− x (AsF 6) x , 0 ⪯ x ⪯ 1, THF = tetrahydrofuran) was analysed by static magnetic susceptibility (χ), radiofrequency and microwave electron spin resonance (ESR), (g-factor, line width ΔB), and microwave conductivity (σ). According to crystal structure analyses, these salts have a five-eighth filled conduction band. The opening of the energy gap at 100 – 120 K (depending on x) was determined by the analysis of χ(T). Additional phase transitions were observed and analysed by the different experimental techniques (χ(T), σ(T), g(T)). Due to the narrow ESR line in the metallic phase ( ΔB pp ≅ 15 mG), a reorientation of the PE-stacks at 162 K can be derived precisely via the g-anisotropy. In the low-temperature phase the angular and frequency dependence of the ESR lines' boardening is used in order to analyse the interaction between thermally activated conduction electrons and localized defects in these quasi-onedimensional conductors.