Search results for "trimethylsilyl"
showing 10 items of 206 documents
Synthesis, Structural Characterisation and Reactivity of New Dinuclear Monocyclopentadienyl Imidoniobium and ‐tantalum Complexes − X‐ray Crystal Stru…
2004
The preparation of a family of dinuclear monocyclopentadienyl imidoniobium and -tantalum complexes was achieved by two different synthetic routes. The diimido complexes [{M(Cp′)Cl2}2(μ-1,i-NC6H4N)] [Cp′ = η5-C5H4SiMe3, M = Nb, i = 4 (1); Cp′ = η5-C5H4SiMe3, M = Nb, i = 3 (2); Cp′ = η5-C5H4SiMe3, M = Nb, i = 2 (3); Cp′ = η5-C5Me5, M = Nb, i = 4 (4); Cp′ = η5-C5Me5, M = Nb, i = 3 (5); Cp′ = η5-C5H4SiMe3, M = Ta, i = 4 (6); Cp′ = η5-C5H4SiMe3, M = Ta, i = 3 (7)] were prepared by the reaction of one equivalent of the trichloro precursor [{MCl3}2(μ-1,i-NC6H4N)] (M = Nb, Ta, i = 4, 3 or 2) with two equivalents of either C5H4(SiMe3)2 or C5Me5(SiMe3). Complexes 1−7 can also be prepared by the react…
Synthesis and reactivity of new mono- and dinuclear niobium and tantalum imido complexes: X-ray crystal structure of [Ta(η5-C5H4SiMe3)Cl2{NC6Me4-4-(N…
2006
Abstract The reaction of [1,4-{SiMe3(H)N}2C6Me4] (1) with 2 equivalents of LiBun followed by the addition of SiMe3Cl gave the diamine compound [1,4-{(SiMe3)2N}2C6Me4] (2). [Ta(η5-C5H4SiMe3)Cl4] reacts with 2, in a 2:1 stoichiometric ratio, to initially yield a mixture of the dinuclear, [{Ta(η5-C5H4SiMe3)Cl2}2(μ-1,4-NC6Me4N)] (3), and mononuclear, [Ta(η5-C5H4SiMe3)Cl2{ NC6Me4-4-(N(SiMe3)2)}] (4), imido complexes. 3 can be obtained exclusively by submitting the reaction mixture to repeated cycles of evacuation, to remove volatiles, followed by addition of solvent and subsequent heating. The mononuclear imido complex 4 was isolated from the reaction of [Ta(η5-C5H4SiMe3)Cl4] with 2 in a 1:1 sto…
Hindering the formation of ferrocenes: mono(cyclopentadienyl)halo iron complexes [Fe(C5R5)X] containing a sterically bulky cyclopentadienyl ligand
2001
Abstract The reaction of lithium 1,2,4-tris(trimethylsilyl)cyclopentadienide Li(Si 3 Cp) with ferrous halide FeX 2 (X=Cl, Br, I) in THF at −95 °C gives a thermally extremely sensitive compound that can be regarded as a functional equivalent for the 14-electron fragment [Fe(Si 3 Cp)X]. Experiments to trap this species with TMEDA gives thermally sensitive, colorless, paramagnetic crystals of the composition [LiFe(Si 3 Cp)Cl 2 (TMEDA) 3 ]. Trimethylphosphite gives isolable 18-electron half-sandwich complexes [Fe(Si 3 Cp){P(OMe) 3 } 2 X]. [Fe(Si 3 Cp)X] is also formed by reducing the ferric derivative [Fe(Si 3 Cp)Cl 2 ] with zinc. Analogous reactivity towards ferrous halides is observed for the…
Syntheses and properties of some exo,exo-bis(isodicyclopentadienyl)titanium low-valent complexes
2002
Abstract The paramagnetic compounds exo,exo-bis(η5-isodicyclopentadienyl)chlorotitanium(III) (3) and its analogue with trimethylsilyl-substituted isodicyclopentadienide (isodiCp) ligand (4), and the similar pair of diamagnetic exo,exo-bis(isodicyclopentadienyl)[η2-bis(trimethylsilyl)ethyne]titanium(II) complexes 5 and 6 were obtained by common reduction procedures from exo,exo-bis(isodicyclopentadienyl)titanium(IV) dichloride (1) and exo,exo-bis[η5-2-(trimethylsilyl)isodicyclopentadienyl]titanium(IV) dichloride (2), respectively. As indicated by ESR spectroscopy compound 3 is a dimer in the solid state and in frozen toluene glass but monomeric in toluene solution. Compound 4 is monomeric in…
Preparation and nonlinear optics of monodisperse oligo(1,4-phenyleneethynylene)s
2001
Oligo(1,4-phenyleneethynylene)s 1a−e, with solubilizing propoxy side chains, were prepared by use of Hagihara−Sonogashira coupling reactions. The synthetic strategy was based on a building block system and on the use of trimethylsilyl and triisopropylsilyl protecting groups that could be cleaved selectively. The extension of the conjugation with an increasing number of repeat units provokes a bathochromic shift of the long wavelength absorption and a superlinear increase of the second hyperpolarizability |γ|. The corresponding third harmonic generation (THG) measurements were performed using polystyrene matrices and variable laser wavelengths. We conclude that the conjugation length is much…
Persistent radicals of trivalent tin and lead.
2008
In this report we present synthetic, crystallographic, and new electron paramagnetic resonance (EPR) spectroscopic work that shows that the synthetic route leading to the recently reported, first persistent plumbyl radical *PbEbt3 (Ebt = ethylbis(trimethylsilyl)silyl), that is, the oxidation of the related PbEbt3-anion, was easily extended to the synthesis of other persistent molecular mononuclear radicals of lead and tin. At first, various novel solvates of homoleptic potassium metallates KSnHyp3 (4a), KPbHyp3 (3a), KSnEbt3 (4b), KPbIbt3 (3c), and KSnIbt3 (4c) (Hyp = tris(trimethylsilyl)silyl, Ibt = isopropylbis(trimethylsilyl)silyl), as well as some heteroleptic metallates, such as [Li(OE…
CCDC 686639: Experimental Crystal Structure Determination
2009
Related Article: S.-O.Hauber, M.Niemeyer|2008|Z.Anorg.Allg.Chem.|634|2594|doi:10.1002/zaac.200800291
CCDC 213800: Experimental Crystal Structure Determination
2004
Related Article: K.W.Klinkhammer, J.Klett, Yun Xiong, Shenglai Yao|2003|Eur.J.Inorg.Chem.||3417|doi:10.1002/ejic.200300416
CCDC 750476: Experimental Crystal Structure Determination
2011
Related Article: D.Kurzbach, Shenglai Yao, D.Hinderberger, K.-W.Klinkhammer|2010|Dalton Trans.|39|6449|doi:10.1039/c001144d
CCDC 732454: Experimental Crystal Structure Determination
2009
Related Article: A.Alberola, V.L.Blair, L.M.Carrella, W.Clegg, A.R.Kennedy, J.Klett, R.E.Mulvey, S.Newton, E.Rentschler, L.Russo|2009|Organometallics|28|2112|doi:10.1021/om801135d