Reactions of cyclic bis(amino)germylenes and -stannylenes with [CpFe(CO)2]2 and CpFe(CO)2Me (Cp = .eta.5-C5H5) : syntheses and single-crystal x-ray structures of four new insertion compounds

The interaction of El(NtBu)2SiMe2, El = Ge, Sn with CpFe(CO)2Me in toluene has yielded CpFe(CO)2[El(NtBu)2SiMe2]Me, El = Ge (2) and El = Sn (3), respectively. Both compounds have been characterized by NMR, IR, MS, elemental analysis, and single crystal X-ray methods. Compound 2 crystallizes in the monoclinic system, space group P21/m, Z = 2, a = 9.330(6) A°, b = 12.552(9) A°, c = 9.939(7) A°, ß = 105.01(2)°, V = 1124(1) A°3. The isostructural 3 forms orthorhombic crystals of space group Pnma, Z = 4, a = 17.871(9) A°, b = 12.998(7) A°, c = 9.838(5) A°, V = 2285(2) A°3. The refinement of 2 with 1431 unique, observed (I > 2s(I)) reflections led to final agreement indices of R = 0.043, Rw = 0.048. The structure of 3 was refined to R = 0.027 (Rw = 0.027) by using 1397 unique and observed (I > 2s(I)) reflections. Treatment of [CpFe-(CO)2]2 with 2 equiv. of El(NtBu)2SiMe2 under identical reaction conditions afforded [CpFe(CO)2]2Ge(NtBu)2SiMe 2, 4, for the cyclic germylene, whereas in the case of the tin homolog the tetranuclear complex {[CpFe(CO)2Sn(NtBu)2SiMe2] 2·C7H8}, 5, was isolated. Complete characterizations (NMR, IR, MS, EA, single crystal X-ray determination) were carried out on both compounds. The solid state structure of 5 contains one of the longest (2.992(2) A°) unbridged tin-tin bonds known to date. The trinuclear compound 4 is triclinic, space group P1, Z = 2. Its lattice parameters are: a = 9.549(5) A°, b = 10.102(5) A°, c = 16.438(8) A°, a = 81.98(4)°, ß = 74.00(3)°, ? = 62.80(3)°, V = 1355(1) A°3. Refinement of this structure using 3100 unique, observed (I > 2s(I)) data led to agreement indices of R = 0.023 and Rw = 0.023. The tetranuclear 5 crystallizes as a toluene solvate. Crystal data: monoclinic, space group P21/n, Z = 2, a = 10.547(7) A°, b = 19.944(11) A°, c = 11.366(7) A°, ß = 92.36(5)°. Of 3024 collected data 2724 were considered unique and observed (I > 3s(I)) and used in the refinement. Final agreement indices are R = 0.031, Rw = 0.033

Synthese und Strukturen von Bis(amino)germa- und -stanna-Chalkogeniden

Das cyclische Bis(amino)germylen 1 sowie das -stannylen 2 reagieren mit elementarem S, Se oder Te zu Oxidationsprodukten der allgemeinen Formel Me2Si(NtBu)2MEl2M(NtBu)2SiMe2 (M = Ge, El = S (4), El = Se (5), El = Te (6); M = Sn, El = Se (9), El = Te (10)). Nach Röntgenstrukturanalysen (4, 5, 6, 9, 10) bestehen alle Verbindungen aus drei spirocyclisch verbundenen Vierringen SiN2M (2x) und MEl2M, die weitgehend orthogonal zueinander stehen. Die Germanium- und Zinnatome sind folglich verzerrt tetraedrisch koordiniert, während die Chalkogenatome jeweils zwei Nachbaratome unter spitzem Winkel besitzen. Setzt man 1 mit Trimethylamin-N-oxid um, so wird der Sauerstoff an das Germanium übergeben unter Bildung von [Me2Si(NtBu)2GeO]3 (3). Im Gegensatz zu den anderen Verbindungen kann 3 formal als Trimeres aufgefaßt werden: an einem zentralen weitgehend planaren Ge3O3-Sechsring sind spirocyclisch an den Germaniumatomen jeweils drei GeN2Si Vierringe geknüpft (Röntgenstrukturanalyse von 3). In den zentralen Vierringen von 4, 5, 6, 9 und 10 bestehen keine transanularen Wechselwirkungen zwischen den Chalkogenatomen, obwohl diese einen kurzen Abstand untereinander aufweisen. Die gemittelten MEl Abstände betragen: GeO 1,762(5), GeS 2,226(3), GeSe 2,363(3), GeTe 2,592(5), SnSe 2,536(3), SnTe 2,741(3) Å

Verbindungen des Formeltyps M2El2(OtBu)8

By simple salt-exchange processes the starting materials Na2El2(OtBu)6 (El = Ge, Sn, Pb) can be transformed to germanates, stannates and plumbates of divalent magnesium and divalent transition metals. Two types of compounds are formed in these reactions: MEl2(OtBU)6 [El = Ge, M = Mg (1A), Cr (1B), Mn (1C), Zn (1 F); El = Pb, M Mn (3C), M = Zn (3 F)] and M2El2(OtBu)8 [El = Ge, M = Co (1d), Ni (1e); El = Sn, M = Mg (2a), Cr (2b), Mn (2c), Co (2d), Ni (2e); El = Pb, M = Co (3d)]. Single-crystal X-ray diffraction studies have been performed on 1C, 1d, 2a, 2b, 2c, 2d, and 2e, and the structures have been solved. In 1C the Mn atom occupies the center of an elongated O6 octahedron, the germanium(II) atoms displaying pyramidal coordination by three oxygen atoms. The central molecular cage can be described as two MnO3Ge trigonal bipyramids sharing the common central Mn atom and being wrapped by tert-butyl groups linked to the oxygen atoms. The other compounds of the MEl2(OtBU)6 formula seem to be isostructural with the exception of 3F, which displays a H-1-NMR spectrum which is not compatible with this structure. All X-ray structures of the compounds M2El2(OtBu)8 show the same feature: to a central M2(OtBU)2 four-membered ring are spirocyclically connected two M(OtBu)2El rings through the common metal atoms M. The structure is completed by the coordination of an exocyclic tert-butoxy group to the terminal El atoms. The metal atoms M are therefore quasi tetrahedrally coordinated while the Ge and Sn atoms are in pyramidal three-fold oxygen atom environments. All molecules display an El...M...M...El one-dimensional arrangement. From susceptibility measurements it is apparent, that in the compounds MEl2(OtBu)6 and M2El2(OtBu)8 the transition metal atoms are in high-spin configurations, which is also supported by the UV spectra. Analysis of the structural data of the series 2a-2e reveal important contributions of the electronic environments of the transition metal atoms to the M...M and M...Sn distances. A qualitative MO description is used to explain these features. Again it has been shown that the geometrical softness" of Ge(OtBu)3 and Pb(OtBu)3 is greater than of Sn(OtBu)3, as the former two can accomodate Cr2+ and Mn2+ in a sixfold coordination site by two units, while Sn(OtBu)3 coordinates Cr2+ and Mn2+ with only two alkoxy groups. when 1C and 2d are allowed to react with nonacarbonyldiiron Mn-Ge2(OtBu)6 . 2 Fe(CO)4 (4) and Co2Sn2(OtBu)8 . 2 Fe(CO)4 (5), respectively, are formed. Compound 4 displays presumably five metal atoms in a linear arrangement while 5 has six metallic elements arranged in one dimension. The latter fact has been unambigously proved by an X-ray structure determination

Reactions of cyclic bis(amino)germylenes and -stannylenes with [CpFe(CO)2]2 and CpFe(CO)2Me (Cp = .eta.5-C5H5) : syntheses and single-crystal x-ray structures of four new insertion compounds

The interaction of El(NtBu)2SiMe2, El = Ge, Sn with CpFe(CO)2Me in toluene has yielded CpFe(CO)2[El(NtBu)2SiMe2]Me, El = Ge (2) and El = Sn (3), respectively. Both compounds have been characterized by NMR, IR, MS, elemental analysis, and single crystal X-ray methods. Compound 2 crystallizes in the monoclinic system, space group P21/m, Z = 2, a = 9.330(6) A°, b = 12.552(9) A°, c = 9.939(7) A°, ß = 105.01(2)°, V = 1124(1) A°3. The isostructural 3 forms orthorhombic crystals of space group Pnma, Z = 4, a = 17.871(9) A°, b = 12.998(7) A°, c = 9.838(5) A°, V = 2285(2) A°3. The refinement of 2 with 1431 unique, observed (I > 2s(I)) reflections led to final agreement indices of R = 0.043, Rw = 0.048. The structure of 3 was refined to R = 0.027 (Rw = 0.027) by using 1397 unique and observed (I > 2s(I)) reflections. Treatment of [CpFe-(CO)2]2 with 2 equiv. of El(NtBu)2SiMe2 under identical reaction conditions afforded [CpFe(CO)2]2Ge(NtBu)2SiMe 2, 4, for the cyclic germylene, whereas in the case of the tin homolog the tetranuclear complex {[CpFe(CO)2Sn(NtBu)2SiMe2] 2·C7H8}, 5, was isolated. Complete characterizations (NMR, IR, MS, EA, single crystal X-ray determination) were carried out on both compounds. The solid state structure of 5 contains one of the longest (2.992(2) A°) unbridged tin-tin bonds known to date. The trinuclear compound 4 is triclinic, space group P1, Z = 2. Its lattice parameters are: a = 9.549(5) A°, b = 10.102(5) A°, c = 16.438(8) A°, a = 81.98(4)°, ß = 74.00(3)°, ? = 62.80(3)°, V = 1355(1) A°3. Refinement of this structure using 3100 unique, observed (I > 2s(I)) data led to agreement indices of R = 0.023 and Rw = 0.023. The tetranuclear 5 crystallizes as a toluene solvate. Crystal data: monoclinic, space group P21/n, Z = 2, a = 10.547(7) A°, b = 19.944(11) A°, c = 11.366(7) A°, ß = 92.36(5)°. Of 3024 collected data 2724 were considered unique and observed (I > 3s(I)) and used in the refinement. Final agreement indices are R = 0.031, Rw = 0.033

Projektbericht Vergleichsuntersuchung MESSENGER - FULCRUM

"In einem Benutzertest wird die Leistungsfähigkeit des auf automatischer Indexierung basierenden Retrievalinstruments FULCRUM, das die Inhaltsdeskribierung des IZ nicht benutzt und ein nach Relevanz geranktes Suchergebnis liefert, mit der Standardfreitextsuche des Retrievalinstruments MESSENGER, das um die intellektuell vom IZ vergebenen Deskriptoren ergänzt ist, verglichen. Die Ergebnisse zeigen, dass in FULCRUM das Boolesche Exakt-Match-Retrieval dem Vektor-Space-Modell (Best-Match-Verfahren) von den Versuchspersonen vorgezogen wurde. Die in MESSENGER realisierte Mischform aus intellektueller und automatischer Indexierung erwies sich gegenüber dem quantitativ-statistischen Ansatz beim Recall als überlegen." (Autorenreferat

Neutrino Physics with JUNO

The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purposeunderground liquid scintillator detector, was proposed with the determinationof the neutrino mass hierarchy as a primary physics goal. It is also capable ofobserving neutrinos from terrestrial and extra-terrestrial sources, includingsupernova burst neutrinos, diffuse supernova neutrino background, geoneutrinos,atmospheric neutrinos, solar neutrinos, as well as exotic searches such asnucleon decays, dark matter, sterile neutrinos, etc. We present the physicsmotivations and the anticipated performance of the JUNO detector for variousproposed measurements. By detecting reactor antineutrinos from two power plantsat 53-km distance, JUNO will determine the neutrino mass hierarchy at a 3-4sigma significance with six years of running. The measurement of antineutrinospectrum will also lead to the precise determination of three out of the sixoscillation parameters to an accuracy of better than 1\%. Neutrino burst from atypical core-collapse supernova at 10 kpc would lead to ~5000inverse-beta-decay events and ~2000 all-flavor neutrino-proton elasticscattering events in JUNO. Detection of DSNB would provide valuable informationon the cosmic star-formation rate and the average core-collapsed neutrinoenergy spectrum. Geo-neutrinos can be detected in JUNO with a rate of ~400events per year, significantly improving the statistics of existing geoneutrinosamples. The JUNO detector is sensitive to several exotic searches, e.g. protondecay via the $p\to K^++\bar\nu$ decay channel. The JUNO detector will providea unique facility to address many outstanding crucial questions in particle andastrophysics. It holds the great potential for further advancing our quest tounderstanding the fundamental properties of neutrinos, one of the buildingblocks of our Universe

Minimal information for studies of extracellular vesicles 2018 (MISEV2018):a position statement of the International Society for Extracellular Vesicles and update of the MISEV2014 guidelines

The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles (“MISEV”) guidelines for the field in 2014. We now update these “MISEV2014” guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV-associated functional activities. Finally, a checklist is provided with summaries of key points

Potential of Core-Collapse Supernova Neutrino Detection at JUNO

JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

Detection of the Diffuse Supernova Neutrino Background with JUNO

As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO