[1,2-Bis(diphenyl­phosphino)ethane]{2-[bis­(diphenyl­phosphinometh­yl)amino]pyridinium}fluoridohydrazidato­molybdenum(IV) bis­(tetra­fluoridoborate)

In the crystal structure of the title compound, [MoF(N2H2)(C31H29N2P2)(C26H24P2)](BF4)2, each Mo atom is surrounded by four P atoms of one 1,2-bis­(diphenyl­phosphino)ethane and one 2-[bis­(diphenyl­phosphinometh­yl)amino]pyridinium ligand. The remaining binding sites of the distorted octa­hedron are occupied by a hydrazidate (NNH2 2−) and a fluoride ligand. Two F atoms of an anion are disordered over two positions; the site occupancy factors are ca 0.7 and 0.3

Spin-Crossover Molecules on Surfaces: From Isolated Molecules to Ultrathin Films

Molecular spintronics seeks to use single or few molecules as functional building blocks for spintronic applications, directly relying on molecular properties or properties of interfaces between molecules and inorganic electrodes. Spin-crossover molecules (SCMs) are one of the most promising classes of candidates for molecular spintronics due to their bistability deriving from the existence of two spin states that can be reversibly switched by temperature, light, electric fields, etc. Building devices based on single or few molecules would entail connecting the molecule(s) with solid surfaces and understanding the fundamental behavior of the resulting assemblies. Herein, the investigations of SCMs on solid surfaces, ranging from isolated single molecules (submonolayers) to ultrathin films (mainly in the sub-10 nm range) are summarized. The achievements, challenges and prospects in this field are highlighted

[Bis(diphenyl­phosphino)methane-κ2 P,P′][bis­(diphenyl­phosphinometh­yl)diethoxy­silane-κ2 P,P′]bis­(dinitro­gen)­molybdenum(0) benzene 0.7-solvate

In the crystal structure of the title compound, [Mo(C25H22P2)(C30H34O2P2Si)(N2)2]·0.7C6H6, the Mo atoms are coordinated by four P atoms and two N atoms in a distorted octa­hedral mode. The two C atoms of one of the two eth­oxy groups are disordered and were refined using a split model and site-occupation factors of 0.7:0.3. The crystal structure contains a benzene solvent mol­ecule with a site occupation of 70%

Experimental Investigations of the Multiple Impulse Energy Handling Capability of Metal-Oxide Varistors for Applications in Electrical Power Engineering Translation of: Experimentelle Untersuchungen zur Mehrfachimpulsbelastbarkeit von Metalloxidvaristoren für Anwendungen in der elektrischen Energietechnik

In this thesis, the results of the research on multiple impulse energy handling capability of metal-oxide varistors (MOVs) are described. The focus here is on repetitive impulse stresses with a high energy density where the specimens cool down to ambient temperature after each energy injection. The repetitive energy injection handling capability of MOVs is compared to their single impulse energy handling capability. It is widely known that the single impulse energy handling capability of MOVs increases with the current density of the impulse stress. This is due to the homogeneous current distribution within MOVs when applying higher current densities. The findings described in this thesis suggest that the temperature dependence of electrical resistance causes a further homogenization of the current distribution within the material of the MOVs at higher current densities. However, the impact of this seems to be small as its influence on the single impulse energy handling capability of the MOVs is not measurable. Furthermore, the results of experiments conducted for this thesis show that short interruptions of longduration current impulse stresses up to the range of seconds do not increase the impulse energy handling capability of MOVs. Additionally, the research results illustrate that the repetitive impulse energy handling capability of MOVs does not correlate with their single impulse energy handling capability. Concerning repetitive energy injections at lower current densities, the stress handling capability is very close to the single impulse energy handling capability. However, repetitive impulse stresses with higher current densities cause a reduced stress handling capability compared to the single impulse energy handling capability. Nonetheless, the energy handling capability when applying repetitive energy injections does not drop below the characteristic volume-related nominal energy handling capability of standard surge arresters. With regard to these findings, it is also shown that a change in reference voltage due to prior repetitive stressing of the MOV is not a sure sign for a pre-damage that leads to a decrease in single impulse energy handling capability. The results gained from this research are discussed with regard to routine tests of MOVs, the usage of surge arresters within electric power systems and the international standardization of surge arresters

Zur Ergotismusepidemie im Regierungsbezirk Breslau

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Kupfer‐katalysierte Monooxygenierung von Phenolen: Evidenz für einen mononuklearen Reaktionsmechanismus

Die CuI-Salze [Cu(CH3CN)4]PF und [Cu(oDFB)2]PF mit dem sehr schwach koordinierenden Anion Al(OC(CF3)3)4− (PF), sowie [Cu(NEt3)2]PF mit dem einzigartigen, linearen Bis-Triethylamin-Komplex [Cu(NEt3)2]+ wurden synthetisiert und als Katalysatoren für die Umwandlung von Monophenolen zu o-Chinonen untersucht. Die Aktivitäten dieser CuI-Salze bei der Monooxygenierung von 2,4-Di-tert-butylphenol (DTBP-H) wurden mit denen der [Cu(CH3CN)4]X-Salze mit “klassischen” Anionen (BF4−, OTf−, PF6−) verglichen, wobei ein Anioneneffekt auf die Aktivität des Katalysators und ein Ligandeneffekt auf die Reaktionsgeschwindigkeit festgestellt wurden. Letztere wird durch den Einsatz von CuII-Semichinon-Komplexen als Katalysatoren drastisch erhöht, was darauf hinweist, dass die Bildung eines CuII-Komplexes dem eigentlichen katalytischen Zyklus vorausgeht. Diese und andere experimentelle Erkenntnisse zeigen, dass die Oxygenierung von Monophenolen mit den oben genannten Systemen nicht einem dinuklearen, sondern einem mononuklearen Weg folgt, analog zur Topachinon-Cofaktor-Biosynthese im Enzym Aminoxidase

Dinuclear Copper(I) Complexes Supported by Bis‐Tridentate N‐Donor‐Ligands: Turning‐On Tyrosinase Activity

Four structurally related bis-tridentate N-donor ligands with either two secondary amine or two imine functions were synthesized, and the corresponding dicopper(I) complexes were investigated as catalysts for the tyrosinase-like conversion of 2,4-di-tert-butylphenol (DTBP-H) to 3,5-di-tert-butylquinone (DTBQ). Notably, the imine systems show evidence for both a μ-η2 : η2-peroxo-dicopper(II) species and catalytic conversion of DTBP-H to DTBQ. Moreover, kinetic studies indicate that a dinuclear copper-oxygen species is involved in the monooxygenation of DTBP-H. In contrast, the amine systems do not show monooxygenase activity. Comparison of the experimentally determined catalytic activities with DFT-optimized geometries of μ-η2 : η2-peroxo-dicopper(II) intermediates suggests that the ligand rigidity of the imine systems allows equatorial attack of the substrate and, thus, subsequent monooxygenation whereas this is not possible in the amine systems due to the fact that no free equatorial positions are available in the μ-peroxo intermediate

Long Term Partial Discharge Behavior of Protrusion Defect in HVDC GIS

2022 IEEE. Personal use of this material is permitted. Permissíon from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertisíng or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.[EN] This article investigates the partial discharge (PD) behavior of protrusion defects in real-size high-voltage direct current gas insulated switchgear (HVDC GIS) for SF6 and SF6 alternative gases including fluoronitrile-CO2 mixture (10%) and fluoroketone-dry air mixture (6.6%). The evolution of PD apparent charge and PD repetition rate for all investigated gases is presented and discussed. The measurement results indicate that PD behavior changes as a function of time. The PD apparent charge increases and the PD repetition rate decreases with the increase of voltage application time. This evolution can be related to the change in protrusion tip radius due to electrochemical etching: radius of the protrusion's tip being enlarged. In addition, the pulse sequence analysis (PSA) plots of the PDs caused by this defect are presented. It is observed that the PSA plots change over time. Therefore, for the development of a robust PD monitoring and defect-recognition tool, as well as for the assessment of risks in the operation of HVDC GIS, it is crucial to take these changes into account.This work was supported in part by the Horizon 2020 Progress on Meshed HVDC Offshore Transmission Networks (PROMOTioN) Project under Grant 691714 and in part by the French Government through the frame of "Investissements d'avenir," under Grant ANE-ITE-002-01.Vu, C.; Toigo, C.; Jacquier, F.; Girodet, A.; Riechert, U.; Tuczek, MN.; Rodrigo Mor, A. (2022). Long Term Partial Discharge Behavior of Protrusion Defect in HVDC GIS. IEEE Transactions on Dielectrics and Electrical Insulation. 29(6):2294-2302. https://doi.org/10.1109/TDEI.2022.32067262294230229

physicochemical properties in the crystalline bulk and in thin films deposited from the gas phase

Four analogues of the spin-crossover complex [Fe(H2Bpz2)2(phen)] (H2Bpz2 = dihydrobis(pyrazolyl)borate; 2) containing functionalized 1,10-phenanthroline (phen) ligands have been prepared; i.e., [Fe(H2Bpz2)2(L)], L = 4-methyl-1,10-phenanthroline (3), 5-chloro-1,10-phenanthroline (4), 4,7-dichloro-1,10-phenanthroline (5), and 4,7-dimethyl-1,10-phenanthroline (6). The systems are investigated by magnetic susceptibility measurements and a range of spectroscopies in the solid state and in thin films obtained by physical vapour deposition (PVD). Thermal as well as light-induced SCO behaviour is observed for 3–6 in the films. By contrast, thermal SCO in the solid state occurs only for 3 and 4 but is absent for 5 and 6. These findings are discussed in the light of cooperative and intermolecular interactions

Toward a Decision Support System for Mitigating Urban Heat

With the continuous rise of global urbanization, city planners and policymakers are increasingly concerned with urban heat islands (UHI), which are metropolitan areas that are significantly warmer than their surrounding rural areas. We address the United Nation’s Sustainable Development Goal 11 “Sustainable Cities and Communities,” and we design and develop a decision support system (DSS), which will help city planners and policymakers to overcome economic barriers to reach environmental sustainability goals