The synthesis and crystalstructures of samarium complexes incorporating bridged Cp′SiMe2allenyl/propargyl ligands [Cp′=(Me3Si)2(C5H2)] are described. The reaction of a dilithiumsalt of [(Me3Si)2(C5H3)]SiMe2CH2CCSiMe3 (1a) with SmCl3 yielded an η3-allenyl complex [(Me3Si)2(C5H2)]SiMe2(η3-CCC[H]SiMe3)}SmCl3Li2(TMEDA)2 (2a) (TMEDA=N,N,N′,N′-tetramethylethylenediamine). On the other hand, the reaction
Isospecific polymerizations of alkyl methacrylates with a bis(alkyl)Yb complex and formation of stereocomplexes with syndiotactic poly(alkyl methacrylate)s
modulus is higher than the respective isotactic and syndiotactic poly(MMA)s. Yb[C(SiMe3)3]2 also generated isotactic (98%) poly[2-(dimethylamino)ethyl methacrylate] (DMEMA), and (C5Me5)2SmMe(THF) affords the syndiotactic (97%) polymer in high yields. The combination of isotactic poly(MMA)-block-poly(DMEMA) (97/3) and syndiotactic poly(MMA)-block-poly(DMEMA) (97/3) provides the amphiphathic stereocomplex
Yb [C(SiMe 3)3 ] 2引发甲基丙烯酸甲酯(MMA)在-78°C下的活性聚合,得到的M n为51.0×10 4(M w / M n = 1.1)和高全同立构规整度( 97%)。将所得聚合物(M n = 16.3×10 4)的丙酮溶液与由(C 5 Me 5)2制备的间规聚(MMA)(M n = 15.7×10 4)的丙酮溶液混合SmMe(THF)引发剂以很高的T m生成所需的立体复合物,其T m很高,其拉伸模量高于各自的等规和间规聚(MMA)。Yb [C(SiMe 3)3 ] 2也生成等规(98%)聚[甲基丙烯酸2-(二甲氨基)乙酯](DMEMA),(C 5 Me 5)2 SmMe(THF)提供间同立构(97%)高产的聚合物。-全同立构的聚(MMA)的组合块-聚(DMEMA)(97/3)和间规聚(MMA) -嵌段-聚(DMEMA)(97/3)提供了两亲性立体络合物。与Yb [C(SiMe
Synthesis, structure and reactions of organometallic compounds of Groups 1–3 containing bulky silicon-substituted alkyl groups
作者:Colin Eaborn、Keith Izod、J.David Smith
DOI:10.1016/0022-328x(95)00528-x
日期:1995.9
review is presented of the chemistry of organometallic compounds containing very bulky ligands of the types C(SiMe2X)3 (X = Me, Ph or OMe) and C(SiMe3)2(SiMe2X) (X = Ph or OMe) attached to metals of Groups 1–3. The structures and reactions of these compounds show novel features not observed for analogues containing less bulkyalkylgroups.
The first structurally characterised solvent-free ς-bonded diorganocalcium, Ca[C(SiMe3)3]2
作者:Colin Eaborn、Peter B. Hitchcock
DOI:10.1039/a703972g
日期:——
The monomeric solvent-free compound CaR2 1 [R = C(SiMe3)3] is obtained as colourless air- and moisture-sensitive crystals from the reaction between KR and CaI2; in the solid the CâCaâC axis is bent with CaâC 2.459(9) à and CâCaâC 149.7(6)°; reactions of 1 with ethers ROEt give RH, ethene and Ca(OEt)2.
Multinuclear NMR Study of the Solution Structure and Reactivity of Tris(trimethylsilyl)methyllithium and its Iodine Ate Complex
作者:Hans J. Reich、William H. Sikorski、Aaron W. Sanders、Amanda C. Jones、Kristin N. Plessel
DOI:10.1021/jo802032d
日期:2009.1.16
The extreme steric bulk of tris(trimethylsilyl)methyl derivatives (1-X) provides interesting structural and dynamic behavior for study. Dynamic NMR studies on 1-SePh and 1-I showed restricted rotation around the C−Si bonds of each trimethylsilyl groups. An extensive multinuclear NMR study of natural abundance and 6Li and 13C enriched 1-Li revealed three species in THF-containing solvents, a dimer 1T