Beiträge zum 29. Darmstädter Geotechnik-Kolloquium am 7. März 2024

Themenschwerpunkte: 1. Klimawandelfolgen und Nachhaltigkeit 2. Digitalisierung und künstliche Intelligenz 3. Planung und Bemessung von Infrastrukturprojekten 4. Großprojekt

Synthesis, Structure, and Reactivity of Pentamethylcyclopentadienyl 2,4,6-Triphenylphosphinine Iron Complexes

The potassium salt [K([18]­crown-6)­(THF)₂]­[Cp*Fe­(η⁴-2,4,6-triphenyl­phosphinine)}] (<b>K1</b>, Cp* = C₅Me₅) can be isolated in 68% yield by reacting the anionic naphthalene complex [K([18]­crown-6)­{Cp*Fe­(η⁴-C₁₀H₈)}] (C₁₀H₈ = naphthalene) with 2,4,6-triphenylphosphinine. Compound <b>K1</b> reacts with water to afford [K([18]-crown-6)]­{Cp*Fe­(η⁴-2,4,6-triphenyl-2,3-dihydrophosphinine 1-oxide)}] (<b>K2</b>) with a novel 2,3-dihydrophosphinine 1-oxide ligand. Oxidation of <b>K1</b> with one equivalent of ferrocenium hexafluorophosphate yields the P–P-bonded diphosphinine complex [Cp*Fe­(η⁵-2,4,6-triphenyl­phosphinine)]₂ (<b>3</b>), while the iodide salt [Cp*Fe­(η⁶-2,4,6-triphenyl­phosphinine)]­I (<b>4</b>) can be obtained by reacting <b>K1</b> with one equivalent of iodine. Reactions of <b>4</b> with LiNMe₂, Cp*Li, LiBHEt₃, and Ga­(nacnac^Dipp) (nacnac^Dipp = HC­{C­(Me)­N­(C₆H₃-2,6-<i>i</i>Pr₂)}₂) afford [Cp*Fe­(η⁵-1-dimethylamino-2,4,6-triphenyl­phosphacyclohexadienyl)] (<b>5</b>), [Cp*Fe­(η⁵-1-(η¹-Cp*)-2,4,6-triphenyl­phosphacyclohexadienyl)] (<b>6</b>), [Cp*Fe­(η⁵-1-hydro-2,4,6-triphenyl­phosphacyclohexadienyl)] (<b>7</b>), and [Cp*Fe­((η⁵-1-{Ga­(nacnac^Dipp)­I}-2,4,6-triphenyl­phosphacyclohexadienyl] (<b>8</b>). The molecular structures of <b>5</b>–<b>8</b> display η⁵-coordinated λ³σ³-phosphinine anions. All new complexes were fully characterized by spectroscopic techniques (¹H, ¹³C, and ³¹P NMR, UV–vis, and IR spectroscopy), elemental analysis, and X-ray crystallography. The electronic structures of these new phosphinine complexes were investigated theoretically at the DFT level, using molecular orbital and population analyses. The nature of the electronic transitions observed in the UV–vis spectra was analyzed using TD-DFT calculations

Synthesis, Structure, and Reactivity of Pentamethylcyclopentadienyl 2,4,6-Triphenylphosphinine Iron Complexes

The potassium salt [K([18]­crown-6)­(THF)₂]­[Cp*Fe­(η⁴-2,4,6-triphenyl­phosphinine)}] (<b>K1</b>, Cp* = C₅Me₅) can be isolated in 68% yield by reacting the anionic naphthalene complex [K([18]­crown-6)­{Cp*Fe­(η⁴-C₁₀H₈)}] (C₁₀H₈ = naphthalene) with 2,4,6-triphenylphosphinine. Compound <b>K1</b> reacts with water to afford [K([18]-crown-6)]­{Cp*Fe­(η⁴-2,4,6-triphenyl-2,3-dihydrophosphinine 1-oxide)}] (<b>K2</b>) with a novel 2,3-dihydrophosphinine 1-oxide ligand. Oxidation of <b>K1</b> with one equivalent of ferrocenium hexafluorophosphate yields the P–P-bonded diphosphinine complex [Cp*Fe­(η⁵-2,4,6-triphenyl­phosphinine)]₂ (<b>3</b>), while the iodide salt [Cp*Fe­(η⁶-2,4,6-triphenyl­phosphinine)]­I (<b>4</b>) can be obtained by reacting <b>K1</b> with one equivalent of iodine. Reactions of <b>4</b> with LiNMe₂, Cp*Li, LiBHEt₃, and Ga­(nacnac^Dipp) (nacnac^Dipp = HC­{C­(Me)­N­(C₆H₃-2,6-<i>i</i>Pr₂)}₂) afford [Cp*Fe­(η⁵-1-dimethylamino-2,4,6-triphenyl­phosphacyclohexadienyl)] (<b>5</b>), [Cp*Fe­(η⁵-1-(η¹-Cp*)-2,4,6-triphenyl­phosphacyclohexadienyl)] (<b>6</b>), [Cp*Fe­(η⁵-1-hydro-2,4,6-triphenyl­phosphacyclohexadienyl)] (<b>7</b>), and [Cp*Fe­((η⁵-1-{Ga­(nacnac^Dipp)­I}-2,4,6-triphenyl­phosphacyclohexadienyl] (<b>8</b>). The molecular structures of <b>5</b>–<b>8</b> display η⁵-coordinated λ³σ³-phosphinine anions. All new complexes were fully characterized by spectroscopic techniques (¹H, ¹³C, and ³¹P NMR, UV–vis, and IR spectroscopy), elemental analysis, and X-ray crystallography. The electronic structures of these new phosphinine complexes were investigated theoretically at the DFT level, using molecular orbital and population analyses. The nature of the electronic transitions observed in the UV–vis spectra was analyzed using TD-DFT calculations

Online characterization of regulated and unregulated gaseous and particulate exhaust emissions from two-stroke mopeds: A chemometric approach

Two-stroke mopeds are a popular and convenient mean of transport in particular in the highly populated cities. These vehicles can emit potentially toxic gaseous and aerosol pollutants due to their engine technology. The legislative measurements of moped emissions are based on offline methods; however, the online characterization of gas and particulate phases offers great possibilities to understand aerosol formation mechanism and to adapt future emission standards. The purpose of this work was to study the emission behavior of two mopeds complying with different European emission standards (EURO-1 and EURO-2). A sophisticated set of online analyzers was applied to simultaneously monitor the gas phase and particulate phase of exhaust on a real time basis. The gaseous emission was analyzed with a high resolution Fourier transform infrared spectrometer (FTIR; nitrogen species) and a resonance-enhanced multiphoton ionization time-of-flight mass spectrometer (REMPI-ToF-MS; polycyclic aromatic hydrocarbons: PAH), whereas the particulate phase was chemically characterized by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS; organic, nitrate and chloride aerosol) and a multiangle absorption photometer (MAAP; black carbon). The physical characterization of the aerosol was carried out with a condensation particle counter (CPC; particle number concentration) and a fast mobility particle sizer (FMPS; size distribution in real time). In order to extract underlying correlation between gas and solid emissions, principal component analysis was applied to the comprehensive online dataset. Multivariate analysis highlighted the considerable effect of the exhaust temperature on the particles and heavy PAH emissions. The results showed that the after-treatment used to comply with the latest EURO-2 emission standard may be responsible for the production of more potentially harmful particles compared to the EURO-1 moped emissions

Triazaphospholes versus Triazoles: An Investigation of the Differences between “Click”-Derived Chelating Phosphorus- and Nitrogen-Containing Heterocycles

A new class of pyridyl-functionalized triazaphospholes bearing either ^<i>t</i>Bu or SiMe₃ substituents at the 5-position of the N₃PC heterocycle have been prepared via the “click” reaction starting from 2-(azidomethyl)­pyridine and the corresponding phosphaalkynes. In order to investigate the electronic structure and donor–acceptor properties of such novel chelating and low-coordinate phosphorus heterocycles, calculations at the DFT level have been carried out. Moreover, cyclic voltammetry measurements were performed and the results were compared with those for the structurally related triazole-based systems, demonstrating a significant influence of the phosphorus atom as well as the substitution pattern on the electronic properties of the novel compounds. The P,N hybrid ligands form Re­(I) complexes of the type [(N^∧^mN)­Re­(CO)₃Br] via coordination of the nitrogen atom N² to the metal center rather than via the phosphorus atom, as verified crystallographically

Triazaphospholes versus Triazoles: An Investigation of the Differences between “Click”-Derived Chelating Phosphorus- and Nitrogen-Containing Heterocycles

A new class of pyridyl-functionalized triazaphospholes bearing either ^<i>t</i>Bu or SiMe₃ substituents at the 5-position of the N₃PC heterocycle have been prepared via the “click” reaction starting from 2-(azidomethyl)­pyridine and the corresponding phosphaalkynes. In order to investigate the electronic structure and donor–acceptor properties of such novel chelating and low-coordinate phosphorus heterocycles, calculations at the DFT level have been carried out. Moreover, cyclic voltammetry measurements were performed and the results were compared with those for the structurally related triazole-based systems, demonstrating a significant influence of the phosphorus atom as well as the substitution pattern on the electronic properties of the novel compounds. The P,N hybrid ligands form Re­(I) complexes of the type [(N^∧^mN)­Re­(CO)₃Br] via coordination of the nitrogen atom N² to the metal center rather than via the phosphorus atom, as verified crystallographically

Emissions of organic aerosol mass, black carbon, particle number, and regulated and unregulated gases from scooters and light and heavy duty vehicles with different fuels

A sampling campaign with seven different types of vehicles was conducted in 2009 at the vehicle test facilities of the Joint Research Centre (JRC) in Ispra (Italy). The vehicles chosen were representative of some categories circulating in Europe and were 5 fueled either with standard gasoline or diesel and some with blends of rapeseed methyl ester biodiesel. The aim of this work was to improve the knowledge about the emission factors of gas phase and particle-associated regulated and unregulated species from vehicle exhaust. Unregulated species such as black carbon (BC), primary organic aerosol (OA) content, particle number (PN), monocyclic and polycyclic aromatic 10 hydrocarbons (PAHs) and a selection of unregulated gaseous compounds, including nitrous acid (N2O), ammonia (NH3), hydrogen cyanide (HCN), formaldehyde (HCHO), acetaldehyde (CH3CHO), sulfur dioxide (SO2), and methane (CH4), were measured in real time with a suite of instruments including a high-resolution aerosol time-of-flight mass spectrometer, a resonance enhanced multi-photon ionization time-of-flight mass 15 spectrometer, and a high resolution Fourier transform infrared spectrometer. Diesel vehicles, without particle filters, featured the highest values for particle number, followed by gasoline vehicles and scooters. The particles from diesel and gasoline vehicles were mostly made of BC with a low fraction of OA, while the particles from the scooters were mainly composed of OA. Scooters were characterized by super high emissions 20 factors for OA, which were orders of magnitude higher than for the other vehicles. The heavy duty diesel vehicle (HDDV) featured the highest nitrogen oxides (NOx) emissions, while the scooters had the highest emissions for total hydrocarbons and aromatic compounds due to the unburned and partially burned gasoline and lubricant oil mixture. Generally, vehicles fuelled with biodiesel blends showed lower emission 25 factors of OA and total aromatics than those from the standard fuels. The scooters were the main emitters of aromatic compounds, followed by the gasoline vehicle, the diesel vehicles and the HDDV.JRC.C.4-Sustainable Transpor

Application of Modern On-line Instrumentation for Chemical Analysis of Gas Phase and Particulate Phases of Exhaust at the European Commission Heavy-Duty Vehicle Emission Laboratory

The European Commission recently established a novel test facility for heavy duty vehicles to enhance more sustainable transport. The facility enables to study the energy efficiency of various fuels/scenarios as well as the chemical composition of evolved exhaust emissions. Sophisticated instrumentation for real-time analysis of the gas phase and the particulate phase of exhaust has been implemented. Thereby, gas phase characterization was carried out by a Fourier-transformation infrared spectrometer (FTIR: carbonyls, nitrogen-containing species, small hydrocarbons) and a resonance-enhanced multiphoton ionization time-of-flight mass spectrometer (REMPI-TOFMS: monocyclic and polycyclic aromatic hydrocarbons). For the analysis of the particulate phase a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS: organic matter, chloride, nitrate), a condensation particle counter (CPC: particle number), and a multi-angle absorption photometer (MAAP: black carbon) were applied. In this paper, the first application of the new facility in combination with the described instruments is presented, whereby a medium size truck was investigated by applying different driving cycles. Goal was the simultaneous chemical characterization of a great variety of gaseous compounds and particulate matter in exhaust on a real-time basis. The time-resolved data allowed new approaches to view the results e.g. emission factors were normalized to time-resolved consumption of fuel as well as related to emission factors evolved during high speeds. Compounds could be identified, which follow the fuel consumption, others showing a very different behavior. In particular, engine cold start, engine ignition (unburned fuel) and high speed events resulted in unique emission patterns.JRC.DDG.F.9-Sustainable Transport (Ispra

Particulate Matter from Both Heavy Fuel Oil and Diesel Fuel Shipping Emissions Show Strong Biological Effects on Human Lung Cells at Realistic and Comparable In Vitro Exposure Conditions

Background Ship engine emissions are important with regard to lung and cardiovascular diseases especially in coastal regions worldwide. Known cellular responses to combustion particles include oxidative stress and inflammatory signalling. Objectives To provide a molecular link between the chemical and physical characteristics of ship emission particles and the cellular responses they elicit and to identify potentially harmful fractions in shipping emission aerosols. Methods Through an air-liquid interface exposure system, we exposed human lung cells under realistic in vitro conditions to exhaust fumes from a ship engine running on either common heavy fuel oil (HFO) or cleaner-burning diesel fuel (DF). Advanced chemical analyses of the exhaust aerosols were combined with transcriptional, proteomic and metabolomic profiling including isotope labelling methods to characterise the lung cell responses. Results The HFO emissions contained high concentrations of toxic compounds such as metals and polycyclic aromatic hydrocarbon, and were higher in particle mass. These compounds were lower in DF emissions, which in turn had higher concentrations of elemental carbon (“soot”). Common cellular reactions included cellular stress responses and endocytosis. Reactions to HFO emissions were dominated by oxidative stress and inflammatory responses, whereas DF emissions induced generally a broader biological response than HFO emissions and affected essential cellular pathways such as energy metabolism, protein synthesis, and chromatin modification. Conclusions Despite a lower content of known toxic compounds, combustion particles from the clean shipping fuel DF influenced several essential pathways of lung cell metabolism more strongly than particles from the unrefined fuel HFO. This might be attributable to a higher soot content in DF. Thus the role of diesel soot, which is a known carcinogen in acute air pollution-induced health effects should be further investigated. For the use of HFO and DF we recommend a reduction of carbonaceous soot in the ship emissions by implementation of filtration devices

Beiträge zum 29. Darmstädter Geotechnik-Kolloquium am 7. März 2024

Themenschwerpunkte: 1. Klimawandelfolgen und Nachhaltigkeit 2. Digitalisierung und künstliche Intelligenz 3. Planung und Bemessung von Infrastrukturprojekten 4. Großprojekt