Meteorological-tsunami-like (or meteotsunami-like) periodic oscillation was muographically detected with the Tokyo-Bay Seafloor Hyper-Kilometric Submarine Deep Detector (TS-HKMSDD) deployed in the ...underwater highway called the Trans-Tokyo Bay Expressway or Tokyo Bay Aqua-Line (TBAL). It was detected right after the arrival of the 2021 Typhoon-16 that passed through the region 400 km south of the bay. The measured oscillation period and decay time were respectively 3 h and 10 h. These measurements were found to be consistent with previous tide gauge measurements. Meteotsunamis are known to take place in bays and lakes, and the temporal and spatial characteristics of meteotsunamis are similar to seismic tsunamis. However, their generation and propagation mechanisms are not well understood. The current result indicates that a combination of muography and trans-bay or trans-lake underwater tunnels will offer an additional tool to measure meteotsunamis at locations where tide gauges are unavailable.
The asymmetric hydrogenation of benchmark substrates dimethyl itaconate and (
Z
)-α-acetamidocinnamic acid methyl ester with chiral pentane-2,4-diyl-based phosphine–phosphite Rh complexes immobilized ...on the support with heteropolyacid (phosphotungstic acid) as anchoring agent has been studied. The complexes have been supported on commercially available Al
2
O
3
by the Augustine method. The novel heterogeneous catalysts were applied in a high-throughput flow reactor. The effect of the pressure, temperature, substrate concentration, and flow rate was thoroughly screened to optimize reaction conditions. The immobilized catalysts proved to be remarkably stable and could be used 6 h in the microfluidic-based reactor without a significant loss of activity and selectivity. Furthermore, under optimized conditions, the hydrogenation product could be obtained with high activity (TOF >2000 h
−1
) and enantioselectivity (up to 99%
ee
). As the first precedent, the potential of supported Rh(P-OP)-complexes under flow conditions has been presented.
Graphical abstract
Six-membered chelate complexes of type Pd(1a-e)Cl2 (2a-e) and Pd(1a-e)(η3-PhCHCHCHPh)BF4 (3a-e) of a series of systematically varied chiral phosphine-amine ligands (S,S)-Ph2PCH(CH3)CH2CH(CH3)NHR 1a-e ...(R = benzyl 1a, R = ethyl 1b, R = (S)-α-phenylethyl 1c, R = isopropyl 1d, R = methyl 1e) have been studied. The complexes 2a-e were characterized by X-ray crystallography, DFT analysis and in solution by 1D and 2D NMR spectroscopy. A very good correlation has been observed between the steric demand of the N-substituent and the distortion of the chelate. Furthermore, it has been proved that sterically more demanding N-substituents are capable of distorting the chelate to a larger extent along one single, well defined conformational pathway. The careful variation of the N-substituent thus allows a precise stereochemical fine tuning of the metal's coordination sphere. As a substantiation of this concept, the investigation of complexes 3a-e revealed that the exo/endo ratio as well as the twisting of the allyl moiety around the Pd-allyl axis can easily be modified by the proper choice of the nitrogen substituent. Furthermore, Pd-catalysts with ligands 1a-e provided high enantioselectivities (up to 96%) in asymmetric allylic alkylation reactions.
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•Sterically more demanding N-substituents distort the chelate to a larger extent along one single, conformational pathway.•The careful variation of the N-substituent allows a precise stereochemical fine tuning of the metal's coordination sphere.•The rationalization of the geometry allowed the development of a qualitative stereomodel for asymmetric induction.•Highly active and selective (ees up to 96%) Pd catalysts were obtained in allylation reactions.
The degree of human geomorphological impact was estimated as a ratio of natural geomorphological processes and geomorphological processes triggered or facilitated by humankind. A typical Central ...European cultural landscape of diverse land use and relief was considered as a pilot area. Based on topography maps and landforms the natural material fluxes were calculated. By overlapping historical maps, modern maps and remotely sensed data, the duration and extent of different land use types were mapped, and were assigned to each landscape unit. Anthropogenic material fluxes were calculated for the land use types identified. Dividing the summarized anthropogenic material fluxes by natural ones, the anthropic geomorphological transformation ratio (rAG
) was estimated. The value of rAG
is independent of the efficiency and intensity of processes; it merely expresses the relation of effectiveness between human induced and natural processes. Since the calculated index is based on estimated values and there is, at least theoretically, no upper limit, the term ‘hemeromorphy’ was introduced and the values were classified in corresponding ‘hemeromorphy’ categories. For the smallest landscape units with the same degree of ‘hemeromorphy’ the term ‘hemeromorphotop’ was applied. This interpretation makes the comparison of landscape units possible according to their anthropogeomorphological transformation, independently of the intensity and quality of their geomorphological processes.
Der Grad der geomorphologischen Einflüsse des Menschen wird als Verhältnis zwischen natürlichen geomorphologischen Prozessen und durch den Menschen ausgelöste oder begünstigte geomorphologischen Prozessen betrachtet. Eine typische mitteleuropäische Kulturlandschaft mit vielfältiger Landnutzung und Relief wird als Modellgebiet betrachtet. Auf der Grundlage topographischer Karten und Landformen werden zunächst die natürlichen Stoffflüsse berechnet. Durch die Überlagerung von historischen Karten, aktuellen Karten und Fernerkundungsdaten werden Dauer und Ausmaß der verschiedenen Landnutzungstypen kartiert und den einzelnen Landschaftseinheiten zugeordnet. Für die identifizierten Landnutzungstypen werden die anthropogenen Materialflüsse berechnet. Durch die Division der zusammengefassten anthropogenen Materialflüsse durch die natürlichen Materialflüsse wird das anthropogene geomorphologische Transformationsverhältnis (rAG
) geschätzt. Der Wert der rAG
ist unabhängig von der Effizienz und Intensität der Prozesse; er drückt lediglich das Verhältnis der Effektivität zwischen menschlich induzierten und natürlichen Prozessen aus. Da dem berechneten Index geschätzte Werte zugrunde liegen und es, zumindest theoretisch, keine obere Grenze gibt, wird der Begriff ‘Hemeromorphie’ eingeführt und die Werte in entsprechende ‘Hemeromorphie’ Klassen eingeteilt. Für die kleinsten Landschaftseinheiten gleichen ‘Hemeromorphie’ Grads wird der Begriff ‘Hemeromorphotop’ verwendet. Die Interpretation ermöglicht den Vergleich von Landschaftseinheiten entsprechend ihrer anthropo-geomorphologischen Transformation, unabhängig von der Intensität und Qualität der geomorphologischen Prozesse.
Terroir is a concept referring interactions of natural (topography, lithology, climate, soil etc.) and human (economic conditions, traditions, cultivation practices, etc.) factors; therefore, terroir ...is spatially delimited and subjected to environmental, socio-economic, and temporal changes. The geoecological background of wine districts are considered more stable among them, but, because of its natural diversity and the spatial changes of production sites, changes in abiotic terroir components might occur too. In this study the spatial changes of grape production sites in Eger Wine District (Hungary) across two and a half centuries (1784 to 2018), and their consequences on the composition of the geoecological factors (lithology, topography, soil characteristics) were analyzed. Modernization of cultivation, urbanization and increase of builtup areas around the central settlement resulted in decreased concentration, i.e. increased spatial dispersion to more remote vineyards further from Eger. It also has consequences on the lithological and topographical composition of the production sites. Besides the slightly increasing extent of vineyards (from 5346 ha to 7413 ha) we found a distinct decrease of vineyards at higher elevations and a substantial increase at lower elevations. Distribution according to slope gradient changed also remarkably, with the share of vineyards on <5 % slopes from 38 % to 65 %. These changes resulted in transformations of pedological characteristics according to the comparison of vineyard’s extent with soil map data: vineyards shifted to slightly acidic, more fertile (i.e. deeper soil layer with higher organic carbon content) soils. The share of vineyards with different lithology and parent material also changed: loose, calcareous Tertiary sediments decreased almost to half, and the share of vineyards over acidic volcanics and their weathered regoliths almost doubled. Comparing these two dominant lithological types and soil profiles derived from them, different pedological characters and taxonomic status were found (Phaeozems and Vertisols). However, comparison of these two lithological types based on main topsoil characteristics (pH, SOC, carbonates, depth of fertile soil layer, N, P, K content) according to 25 randomly chosen surficial soil samples at production sites, showed no significant differences.. In the case of this particular wine district, spatial changes of the production sites affected mostly the distribution by elevation, by slope gradient, but did not alter significantly the surface soil character of the terroir.
Der Begriff Terroir steht im Weinbau für den originären Charakter eines Weinbauareals durch das Wirkungsgefüge naturräumlicher (Topografie, Lithologie, Klima, Boden usw.) und menschlichen (wirtschaftliche Bedingungen, Traditionen, Anbaupraktiken usw.) Faktoren. Das Terroir ist räumlich begrenzt, unterliegt aber ökologischen, sozioökonomischen und zeitlichen Veränderungen. Zwar gilt der geoökologische Hintergrund der Weinbaugebiete als relativ stabil, aber aufgrund der natürlichen Vielfalt und der räumlichen Veränderungen der Produktionsstandorte können auch Verschiebungen der abiotischen Terroirkomponenten auftreten. In dieser Studie wurden die räumlichen Veränderungen der Weinbauflächen im Weinbaugebiet Eger (Ungarn) über zweieinhalb Jahrhunderte (1784 bis 2018) und ihre Auswirkungen auf die Zusammensetzung der geoökologischen Faktoren (Lithologie, Topografie, Bodeneigenschaften) analysiert. Die Modernisierung des Anbaus, die Verstädterung und die Zunahme der bebauten Areale im zentralen Siedlungsbereich führten zu einer stärkeren räumlichen Streuung auf weiter entfernte Weinberge in der Nähe von Eger. Der Anteil der Weinberge mit unterschiedlicher Lithologie und unterschiedlichem Ausgangsmaterial hat sich dadurch verändert: lockere, kalkhaltige tertiäre Sedimente gingen fast auf die Hälfte zurück, und der Anteil der Weinberge über saurem Vulkangestein und dessen verwitterten Regolithen hat sich fast verdoppelt. Beim Vergleich dieser beiden vorherrschenden lithologischen Typen wurden unterschiedliche bodenkundliche Merkmale und ein unterschiedlicher taxonomischer Status festgestellt (Phäozeme und Vertisole). Ein Vergleich dieser beiden lithologischen Typen anhand der wichtigsten Oberbodenmerkmale (pH, SOC, Karbonate, Tiefe der fruchtbaren Bodenschicht, N-, P- und K-Gehalt) anhand von 25 zufällig ausgewählten oberflächlichen Bodenproben ergab allerdings keine signifikanten Unterschiede. Im Fall der untersuchten Weinbauregion wirkten sich räumliche Veränderungen der Produktionsstandorte vor allem auf die Verteilung nach Höhenlage und Hangneigung aus, veränderten aber nicht wesentlich den Charakter des Oberbodens.
Thioether-phosphite ligands (SP's) with axially chiral (S)-H
0
- or (S)-H
8
-binaphthyl moiety and their Rh(COD)(SP)BF
4
complexes have been synthesized to study their coordination chemistry and ...catalytic features and to compare them to those of the structurally analogous phosphine-phosphites (PP's). NMR exchange studies on Rh(COD)(SP)BF
4
complexes showed selective 1,5-cyclooctadiene dynamics. Firm evidence has been found that this fluxional process involves dissociation of the Rh-sulfur bond. Based on in situ NMR studies, SP ligands can form two types of bis-ligated species at ligand-to-metal ratio higher than 1. Unlike bis-ligated phosphine-phosphite complexes, bis-ligated thioether-phosphite Rh-complexes can efficiently catalyze asymmetric hydrogenation reactions due to their distinct coordination chemistry.
Novel alkane-diyl based heterobidentate P,N and S,N ligands with the general formula R1R2NCH(R3)(CH2)nCH(R4)Q (R1 = Me or iPr; R2 = H or Me; R3, R4 = H or Me; n = 0, 2; Q = PPh2 or SPh) have been ...prepared starting from cyclic sulfate esters or naturally occurring compounds with C1 symmetry. The length of the ligands’ backbone and the reaction conditions applied strongly affected the stereochemical outcome of the synthesis when using cyclic sulfates as starting materials. Palladium(II)-complexes of the new ligands were characterized by 1D and 2D NMR spectroscopy in solution and in several cases by X-ray crystallography in the solid phase. The structural versatility of the ligands enabled the straightforward comparison of the stereoselectivity of their coordination as a function of their tether length, backbone substitution pattern, donor sets and relative carbon atom configuration in their backbone. The catalytic features of the novel compounds were investigated in asymmetric allylic alkylation reactions where the tether length proved to be a crucial factor in determining enantioselectivity.
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Abstract
Six silica-supported phosphotungstic acid catalysts (PTA/SiO
2
) of different composition (20–70 wt% PTA content) have been synthesized and characterized by elemental analysis, BET, BJH, NH
...3
-TPD methods, FT-IR spectroscopy of adsorbed pyridine and
1
H MAS NMR techniques. The new composite catalysts were first applied in the Friedel–Crafts alkylation of toluene with 1-octene as a benchmark process under batch conditions in order to screen their activity and recyclability. The combined analytical techniques together with the catalytic studies enabled the identification of the main factors affecting the activity of the catalysts. Based on these preliminary experiments, the best performing catalyst system (50 wt% PTA/SiO
2
) was investigated in continuous flow mode using an in-house-made flow reactor. The thorough screening of the reaction conditions (temperature, toluene/1-octene molar ratio and flow rate) provided firm evidence that the 50 wt% PTA/SiO
2
composite is highly active, selective and stable catalyst under mild reaction conditions even at elevated flow rate. Additionally, the catalyst used in the flow mode could successfully be regenerated and reused in the alkylation process.
A cyclometalation motif has been discovered in the unprecedented reaction of Pd(II) precursors with simple pentane-2,4-diyl based aminoalkyl-phosphines. The unique six-membered zwitterionic ...palladacycles can easily be synthesized in the presence of 1 molar equiv of oxidant in high yields in a pure form. A comparison between the analogous ligands of different tether lengths revealed that the formation of the zwitterionic palladacycles is the exclusive privilege of the six-membered rings.
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