scholarly journals Nanopatterns of arylene–alkynylene squares on graphite: self-sorting and intercalation

2019 ◽  
Vol 15 ◽  
pp. 1848-1855 ◽  
Author(s):  
Tristan J Keller ◽  
Joshua Bahr ◽  
Kristin Gratzfeld ◽  
Nina Schönfelder ◽  
Marcin A Majewski ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Pyrolytic Graphite ◽  
Scanning Tunneling ◽  
Side Chains ◽  
Tunneling Microscopy ◽  
Polycyclic Aromatic ◽  
Solvent Molecules ◽  
Solid Liquid Interface ◽  
Solid Liquid

Supramolecular nanopatterns of arylene–alkynylene squares with side chains of different lengths are investigated by scanning tunneling microscopy at the solid/liquid interface of highly oriented pyrolytic graphite and 1,2,4-trichlorobenzene. Self-sorting leads to the intermolecular interdigitation of alkoxy side chains of identical length. Voids inside and between the squares are occupied by intercalated solvent molecules, which numbers depend on the sizes and shapes of the nanopores. In addition, planar and non-planar coronoid polycyclic aromatic hydrocarbons (i.e., butyloxy-substituted kekulene and octulene derivatives) are found to be able to intercalate into the intramolecular nanopores.

scholarly journals Self-assembled monolayers of shape-persistent macrocycles on graphite: interior design and conformational polymorphism

2014 ◽  
Vol 10 ◽  
pp. 2774-2782 ◽  
Author(s):  
Joscha Vollmeyer ◽  
Friederike Eberhagen ◽  
Sigurd Höger ◽  
Stefan-S Jester
Keyword(s):  
Interior Design ◽  
Pyrolytic Graphite ◽  
Self Assembled Monolayers ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Conformational Polymorphism ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Solid Liquid Interface ◽  
Solid Liquid

Three shape-persistent naphthylene–phenylene–acetylene macrocycles of identical backbone structures and extraannular substitution patterns but different (empty, apolar, polar) nanopore fillings are self-assembled at the solid/liquid interface of highly oriented pyrolytic graphite and 1,2,4-trichlorobenzene. Submolecularly resolved images of the resulting two-dimensional (2D) crystalline monolayer patterns are obtained by in situ scanning tunneling microscopy. A concentration-dependent conformational polymorphism is found, and open and more dense packing motifs are observed. For all three compounds alike lattice parameters are found, therefore the intermolecular macrocycle distances are mainly determined by their size and symmetry. This is an excellent example that the graphite acts as a template for the macrocycle organization independent from their specific interior.

scholarly journals Capillary force-induced superlattice variation atop a nanometer-wide graphene flake and its moiré origin studied by STM

2019 ◽  
Vol 10 ◽  
pp. 804-810
Author(s):  
Loji K Thomas ◽  
Michael Reichling
Keyword(s):  
Capillary Force ◽  
Orientation Angle ◽  
Scanning Tunneling ◽  
Total Expenditure ◽  
Liquid Interfaces ◽  
Tunneling Microscopy ◽  
Graphene Flake ◽  
Before And After ◽  
Solid Liquid Interface ◽  
Solid Liquid

We present strong experimental evidence for the moiré origin of superlattices on graphite by imaging a live transition from one superlattice to another with concurrent and direct measurement of the orientation angle before and after rotation using scanning tunneling microscopy (STM). This has been possible due to a fortuitous observation of a superlattice on a nanometer-sized graphene flake wherein we have induced a further rotation of the flake utilizing the capillary forces at play at a solid–liquid interface using STM tip motion. We propose a more “realistic” tip–surface meniscus relevant to STM at solid–liquid interfaces and show that the capillary force is sufficient to account for the total expenditure of energy involved in the process.

Solid–liquid equilibrium of some polycyclic aromatic hydrocarbons in wash oil

2012 ◽  
Vol 319 ◽  
pp. 23-29 ◽  
Author(s):  
Yufeng Wei ◽  
Xiangyang Zhang ◽  
Jinyan Zhang ◽  
Leping Dang ◽  
Hongyuan Wei
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Liquid Equilibrium ◽  
Polycyclic Aromatic ◽  
Solid Liquid

scholarly journals The Effects of Three Traditional Smoking Methods on the Concentrations of Polycyclic Aromatic Hydrocarbons (PAHS) in Smoked Fishes

2021 ◽  
pp. 22-30
Author(s):  
Aderinola Oluwatoyin Joseph ◽  
A. A. Adu ◽  
O. O. Babalola ◽  
V. Kusemiju ◽  
G. O. Mekuleyi
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Low Income ◽  
Awareness Campaigns ◽  
Smoked Fish ◽  
Total Pahs ◽  
Scomber Scombrus ◽  
Fish Samples ◽  
Polycyclic Aromatic ◽  
Solid Liquid

The effects of three traditional smoking methods on the concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) in smoked fishes were studied to determine the concentration of PAHs in locally available and commonly consumed smoked fish species. Samples of two highly traded species of fish, Scomber scombrus and Horse markerel, among the low income people for immediate consumption were purchased from the market and processed using sawdust smoke, firewood smoke and charcoal smoke respectively. Some of the fresh fishes were also analyzed as control. The PAHs content were extracted with standard dichloromethane using solid-liquid extraction, and analyzed using Gas chromatography – Mass spectrophotometer (GC-MS) method. The results showed that fish samples processed with sawdust smoke recorded the highest concentrations of total PAHs, having 1.295 mg/kg in Horse markerel and 2.020 mg/kg in Scomber scombrus, followed by firewood smoked samples with total PAHs content of 0.910mg/kg in Horse markrel and 1.175 g/kg in Scomber scombrus while charcoal smoked samples recorded the least total PAHs levels of 0.590 mg/kg in Horse markerel and 0.960 mg/kg in Scomber scombrus. Benzo(a)pyrene concentrations which is usually used to estimate the carcinogenicity of other PAHs was below detection level in both species of fish. PAH4 was proposed by European food safety authority, recommendation level of 30 mg/kg was concluded by the EU regulation. Any PAHs have been associated with intense carcinogenicity in humans, and thus have implication for the quality and safety of these fish products. Therefore, it is imperative that regulatory bodies conduct awareness campaigns to educate the smoked fish processors, traders and consumers on the need to discourage the use of sawdust in smoking fish and adopt safer and improved methods of smoking fishes.

scholarly journals H2 catalysis through superhydrogenation of interstellar polycyclic aromatic hydrocarbons

2019 ◽  
Vol 15 (S350) ◽  
pp. 264-266
Author(s):  
Frederik Doktor S. Simonsen ◽  
Pernille A. Jensen ◽  
Anders W. Skov ◽  
Rijutha Jaganathan ◽  
John D. Thrower ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Cross Section ◽  
Aromatic Hydrocarbons ◽  
Reaction Cross Section ◽  
Pyrolytic Graphite ◽  
Temperature Programmed Desorption ◽  
Reaction Cross ◽  
Initial Reaction ◽  
Polycyclic Aromatic ◽  
Temperature Programmed

AbstractExperimental data showing superhydrogenation of neutral polycyclic aromatic hydrocarbons (PAHs) coronene, pentacene and pentacenequinone is presented. PAH monolayers were prepared on a highly oriented pyrolytic graphite surface and subsequently exposed to a beam of atomic hydrogen. The superhydrogenated PAH species were examined via temperature programmed desorption measurements. Stable intermediate superhydrogenation degrees as well as fully superhydrogenated species are observed and the initial reaction cross section for coronene has been determined.

scholarly journals Dynamic host–guest behavior in halogen-bonded two-dimensional molecular networks investigated by scanning tunneling microscopy at the solid/liquid interface

2020 ◽  
Vol 2 (10) ◽  
pp. 4895-4901
Author(s):  
Yoshihiro Kikkawa ◽  
Mayumi Nagasaki ◽  
Emiko Koyama ◽  
Seiji Tsuzuki ◽  
Thierry Fouquet ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Liquid Interface ◽  
Molecular Networks ◽  
Scanning Tunneling ◽  
Two Dimensional ◽  
Tunneling Microscopy ◽  
2D Structure ◽  
Solid Liquid Interface ◽  
Solid Liquid

Dynamic host–guest behavior is investigated in halogen-bonded molecular networks, and the change in the 2D structure due to guest inclusion is revealed by scanning tunneling microscopy at the solid/liquid interface.

Sorption of Polycyclic Aromatic Hydrocarbons onto Natural Solids: Determination by Fluorescence Quenching Method

1991 ◽  
Vol 23 (1-3) ◽  
pp. 427-436 ◽  
Author(s):  
Y. Shimizu ◽  
H. M. Liljestrand
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Organic Carbon ◽  
Fluorescence Quenching ◽  
Aromatic Hydrocarbons ◽  
Organic Carbon Content ◽  
Polycyclic Aromatic ◽  
Fluorescence Quenching Method ◽  
Quenching Method ◽  
Solid Liquid ◽  
Solid Liquid Separation

A fluorescence quenching method was used to determine the sorption of polycyclic aromatic hydrocarbons (PAHs) onto natural solids in batch experiments. This method is based upon the observation that PAHs fluoresce in aqueous solution but not when associated with natural solids. It avoids problems of incomplete solid-liquid separation. As natural solids, eleven different USEPA soils and sediments were used. Anthracene and 2-aminoanthracene, which are respectively non-ionic and ionic PAHs, were chosen as sorbates. The fractional decrease in fluorescence intensity as a function of added natural solid concentration is referred to as Stem-Volmer plots. The plots were linear for all natural solids investigated. The conditional sorption coefficients (Ksc) at pH 6 through 8 and I=0.1 M were obtained as the slopes of the plots. While the Ksc values of anthracene were independent of pH, the values of 2-aminoanthracene decreased with increasing pH. The Ksc values of anthracene correlated well with the organic carbon content of natural solids. However, the values of 2-aminoanthracene did not depend on the content of organic carbon in natural solids. For 2-aminoanthracene, inorganic matrices of the natural solids may contribute to the sorption.

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