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991.
Prof. Dr. Wolfram W. Seidel Woldemar Dachtler Julia Semmler Marco Tänzler Manuel Folk Dr. Alexander Villinger 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(43):14702-14711
A series of heterodinuclear complexes with acetylene dithiolate (acdt2?) as the bridging moiety were synthesised by a facile one‐pot procedure that avoided use of the highly elusive acetylene dithiol. Generation of the W–Ru complex [Tp′W(CN)(CO)(C2S2)Ru(η5‐C5H5)(PPh3)] (Tp’=hydrotris(3,5‐dimethylpyrazolyl)borate) and the W–Pd complexes [Tp′W(CN)(CO)(C2S2)Pd(dppe)] and [Tp′W(CO)2(C2S2)Pd(dppe)][PF6] (dppe=1,2‐bis(diphenylphoshino)ethane), which exhibit a [W(η2‐κ2‐C2S2)M] core (M=Ru, Pd), was accomplished by using a transition‐metal‐assisted solvolytical removal of the Me3Si‐ethyl thiol protecting groups. All intermediate species of the reaction have been fully characterised. The highly coloured W–Ru complex [Tp′W(CN)(CO)(C2S2)Ru(η5‐C5H5)(PPh3)] shows reversible redox chemistry, as does the prototype complex [Tp′W(CO)2(C2S2)Ru(η5‐C5H5)(PPh3)][PF6]. Single crystal X‐ray diffraction and IR, EPR and UV/Vis spectroscopic studies in conjunction with DFT calculations prove the high electronic delocalisation of states over the acdt2? linker. Comparative studies revealed a higher donor strength and more pronounced dithiolate character of acdt2? in [Tp′W(CN)(CO)(C2S2)Ru(η5‐C5H5)(PPh3)] relative to [Tp′W(CO)2(C2S2)Ru(η5‐C5H5)(PPh3)]+. In addition, the influence of the overall complex charge on the metric parameters was investigated by single‐crystal X‐ray diffraction studies with the W–Pd complexes [Tp′WL2(C2S2)Pd(dppe)] (L=(CN?)(CO) or (CO)2). The central [W(C2S2)Pd] units exhibit high structural similarity, which indicates the extensive delocalisation of charge over both metals. 相似文献
992.
Clever assignments of link weights are able to change communication routes in such a way that loads are distributed almost evenly across a network. This is achieved by weight assignments based on the link load. As demonstrated for scale-free as well as synthetic Internet networks, they decorrelate the loads of the nodes and links from the network structure and increase the transport capacity of the network. For various Internet scans the increase of transport capacity amounts to a factor of around five when compared to shortest-path routing. 相似文献
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ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option. 相似文献
997.
Paul Varava Tak Hin Wong Zhaowen Dong Anastasia Yu. Gitlina Andrzej Sienkiewicz Wolfram Feuerstein Rosario Scopelliti Farzaneh Fadaei-Tirani Kay Severin 《Angewandte Chemie (International ed. in English)》2023,62(25):e202303375
The head-to-tail dimerization of N-heterocyclic diazoolefins is described. The products of these formal (3+3) cycloaddition reactions are strongly reducing quinoidal tetrazines. Oxidation of the tetrazines occurs in a stepwise fashion, and we were able to isolate a stable radical cation and diamagnetic dications. The latter are also accessible by oxidative dimerization of diazoolefins. 相似文献
998.
Doris Pospiech Liane Häußler Dieter Jehnichen Wolfram Kollig Kathrin Eckstein Karina Grundke 《Macromolecular Symposia》2003,198(1):421-434
The goal of the investigation presented here is the development of extremely hydrophobic materials based on polysulfone that can be applied, for instance, as fouling-resistant membrane materials. The concept used is the addition of semifluorinated polymers to polysulfone in suitable blend compositions. The influence of molecular parameters like chain structure of the semifluorinated polymer (segmented block copolymers, random copolymers) and segment molecular weight on the state of phase separation in the bulk and its influence on the surface properties have been systematically examined. It could be shown that segmented block copolymers with semifluorinated polyester segments with intermediate segment molecular weight are more suitable in blends with polysulfone than random polysulfone copolymers having semifluorinated side chains with respect to form homogeneous thin films (coatings) with highly non-wetting properties. 相似文献
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