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21.
Dr. Małgorzata Walewska Dr. Judith Baumgartner Prof. Christoph Marschner Dr. Lena Albers Prof. Thomas Müller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(51):18512-18521
Silylated germylene–PMe3 adducts exchange their phosphane moiety smoothly for an N‐heterocyclic carbene or isocyanide species to form their respective base adducts. Reaction of the silylated germylene–PMe3 adducts with monosubstituted alkynes produce germylene adducts with the alkyne inserted into a Ge?Si bond. A computational study of this process provides evidence for the initial formation of a germirene, which rearranges to a vinylgermylene species. The thermodynamic driving force for this reaction is provided by subsequent adduct formation with PMe3. Reaction of the PMe3 adduct of bis[(trimethylsilyl)silyl]germylene with disubstituted alkynes leads to the formation of stable germirenes, which can be isomerized further to silagermetes. 相似文献
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Arp H Baumgartner J Marschner C Müller T 《Journal of the American Chemical Society》2011,133(15):5632-5635
Reaction of 1,4-dipotassio-1,1,4,4-tetrakis(trimethylsilyl)tetramethyltetrasilane with [(Me(3)Si)(2)N](2)Sn led to the formation of an endocyclic distannene via the dimerization of a transient stannylene. In the presence of strong donor molecules such as PEt(3), the stannylene could be trapped as adduct. Reaction of the PEt(3) derivative with B(C(6)F(5))(3) gave rise to the formation of the stannylene B(C(6)F(5))(3) adduct. 相似文献
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Dörte Diehl Jette Schwarz Marc-O. Goebel Susanne K. Woche Tatjana Schneckenburger Jaane Krüger Anastasia Shchegolikhina Bernd Marschner Friederike Lang Sören Thiele-Bruhn Jörg Bachmann Gabriele E. Schaumann 《Journal of Thermal Analysis and Calorimetry》2014,118(2):1203-1213
Multivalent cations are suggested to influence the supramolecular structure of soil organic matter (SOM) via inter- and intra-molecular interactions with SOM functional groups. In this study, we tested the combined effect of cations, temperature treatment, and isothermal aging on SOM matrix properties. Samples from a peat and a mineral soil were either enriched with Na, Ca, and Al or desalinated in batch experiments. After treatment at 25, 40, 60, and 105 °C and after different periods of aging at 19 °C and 31 % relative humidity, we investigated the physicochemical matrix stability and the thermal stability against combustion. We hypothesized that multivalent cations stabilize the SOM matrix, that these structures disrupt at elevated temperatures, and that aging leads to an increase in matrix stability. The results show that cation-specific effects on matrix rigidity started to evolve in the peat only after 8 weeks of aging and were significantly lower than the temperature effects. Temperature treatment above 40 °C caused a non (or not immediately) reversible loss of water molecule bridges (WaMB) and above 60 °C a partly reversible melting process probably of semi-crystalline poly(methylene). Thermal stability increased with increasing cation valence and degree of protonation and was much less affected by temperature. Generally, Na-treated and control samples revealed lower thermal stability and lower increase in matrix rigidity with aging than those treated with Ca, Al, and H. We conclude that drying at elevated temperatures (>40 °C) may irreversibly change SOM structure via disruption of labile cross-links and melting of semi-crystalline domains. 相似文献
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Wolf-Walther du Mont Hans-Joachim Breunig Herbert Schumann Horst Götz Helga Juds Freimut Marschner 《Journal of organometallic chemistry》1975,96(1):49-56
The PE spectra of [(CH3)3Sn]3N, [(CH3)3E]3P (E = C, Si, Sn), [(CH3)3Si]3As and [(CH3)3E]3Sb (E = C, S, Ge, Sn) are analyzed. The constant level of the ionization potentials of the n-hybrid orbitals of N, P, As, and Sb, together with changes in the hybridization and interactions with ligand MO's is discussed by qualitative MO investigations. 相似文献