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Brian J. Grimmond Joyce Y. Corey Nigam P. Rath 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(1):53-55
The first title metallocene, 1,3‐bis(dichlorotitanocene)‐1,1,3,3‐tetramethyldisiloxane dichloromethane solvate, [(η5‐C5H5)TiCl2(η5‐C5H4SiMe2)]2O·CH2Cl2, (I), crystallizes in space group P21/c. Compound (I) represents the first crystal structure of a bimetallic siloxy‐bridged titanocene. The geometric parameters of (I) are similar to those of the parent titanocene; however, the disiloxane substituents adopt an unexpected eclipsed conformation. The second title metallocene, 1,3‐bis[(pentamethylcyclopentadienyl)(cyclopentadienyl)titanium dichloride]‐1,1,3,3‐tetramethyldisiloxane, [(η5‐C5‐Me5)TiCl2(η5‐C5H4SiMe2)]2O, (II), represents the second crystal structure of a bimetallic siloxy‐bridged titanocene and crystallizes in the space group P21/n. Compound (I) possesses non‐crystallographic twofold molecular symmetry and both metal centers adopt pseudo‐tetrahedral geometries. The geometric parameters of (II) are similar to those of the mixed titanocene Cp*CpTiCl2 (Cp* = C5Me5) and the disiloxane substituents adopt a staggered conformation. 相似文献
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Glen B. Deacon Ewan E. Delbridge Brian W. Skelton Allan H. White 《Angewandte Chemie (International ed. in English)》1998,37(16):2251-2252
A higher degree of coordination saturation is attainable through the unusual coordination mode in the title compound 1 , in which the central pyrazolate groups function both as chelating and as bridging ligands. There is some asymmetry in the bridging, and the N atoms of each μ-η2:η2-pyrazolato ligand are 0.07–0.11 Å closer to one of the two Yb centers. 相似文献
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Masahiro Nagaoka Hiroyuki Tsuruda Dr. Masa‐aki Amako Prof. Dr. Hiroharu Suzuki Prof. Dr. Toshiro Takao 《Angewandte Chemie (International ed. in English)》2015,54(49):14871-14874
A μ3‐η2:η2:η2‐silane complex, [(Cp*Ru)3(μ3‐η2:η2:η2‐H3SitBu)(μ‐H)3] ( 2 a ; Cp*=η5‐C5Me5), was synthesized from the reaction of [{Cp*Ru(μ‐H)}3(μ3‐H)2] ( 1 ) with tBuSiH3. Complex 2 a is the first example of a silane ligand adopting a μ3‐η2:η2:η2 coordination mode. This unprecedented coordination mode was established by NMR and IR spectroscopy as well as X‐ray diffraction analysis and supported by a density functional study. Variable‐temperature NMR analysis implied that 2 a equilibrates with a tautomeric μ3‐silyl complex ( 3 a ). Although 3 a was not isolated, the corresponding μ3‐silyl complex, [(Cp*Ru)3(μ3‐η2:η2‐H2SiPh)(H)(μ‐H)3] ( 3 b ), was obtained from the reaction of 1 with PhSiH3. Treatment of 2 a with PhSiH3 resulted in a silane exchange reaction, leading to the formation of 3 b accompanied by the elimination of tBuSiH3. This result indicates that the μ3‐silane complex can be regarded as an “arrested” intermediate for the oxidative addition/reductive elimination of a primary silane to a trinuclear site. 相似文献
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