Search results for "Metalation"

Solvent induced single-crystal to single-crystal structural transformation and concomitant transmetalation in a 3D cationic Zn(II)-framework.

2015

A 3D cationic Zn(II) framework, based on Zn2(CO2)4 paddle-wheel secondary building units (SBUs) and Zn16(CO2)32 polyhedral supramolecular building blocks (SBBs), has been synthesized. At room temperature, the framework undergoes guest solvent triggered reversible structural transformation and concomitant Zn(II) to Cu(II) transmetalation in a single-crystal to single-crystal fashion.

Titelbild: Direct CH Metalation with Chromium(II) and Iron(II): Transition-Metal Host / Benzenediide Guest Magnetic Inverse-Crown Complexes (Angew. …

2009

Chrom und Eisen als die neuesten Erganzungen des Konzepts der alkalimetallvermittelten Metallierung stellen J. Klett, R. E. Mulvey et al. in ihrer Zuschrift auf S. 3367 ff. vor. Das elektropositivere Natrium ist wesentlich fur die Reaktion, doch das weniger elektropositive Chrom oder Eisen ist es, das Benzol tatsachlich deprotoniert. Diese neuartige Reaktivitat kann mit einem Schachspiel verglichen werden, bei dem die Konigin (Na) dem Konig Schach bietet und der Springer (Cr, Fe) Matt setzt.

Influence of Pendant Arms Bearing Ligating Groups on the Structure of Bismuth Porphyrins: Implications for Labeling Immunoglobulins Used in Medical A…

2004

International audience; The synthesis of two picket bismuth(III) porphyrins is reported, and their crystal structures are compared. The influence of the nature of the pickets, as well as their number, is discussed in terms of stability, kinetics of metalation, structure, and distortion of the porphyrin. Unexpectedly, the resultsindicate that the coordination sphere of bismuth is not affected by different types of distortion nor is the stability of the complex. For both types of complexes, the X-ray crystallography revealed that a single arm is actually in direct interaction with the bismuth cation, thereby allowing furtherfunctionalization on the porphyrin core as the linkage with immunoglo…

C,N-chelated dicyclopentadienylzirconium complexes and their possible use as hydrogenation catalysts

2010

Abstract In situ generated Cp2Zr(n-Bu)Cl (6) reacts with {2-[(CH3)2NCH2]C6H4}2Pb to form exclusively {2-[(CH3)2NCH2]C6H4}Cp2ZrCl (7), [(CH3)2NCH2]C6H5, butene and elemental lead. The further derivatization of chloride (7) to fluoride (8), hydride (9), methyl derivative (10), and a reduction of 7 are also described. The crystal structures of 7–10 were determined. The catalytic activity of 9 and 10 in hydrogenation of styrene was also preliminarily tested.

Stable Carbanions by Quantitative Metalation of Cationically Obtained Diphenylvinyl and Diphenylmethoxy Compounds:  New Initiators for Living Anionic…

1997

Di‐ and Trivalent Ytterbium Complexes Containing Linked Amino‐ and Amidocyclopentadienyl Ligands

2003

Reactions of the aminocyclopentadienes (C5Me4H)SiMe2NHR (R = Et, allyl, nPr, tBu) with [YbI2(THF)2] in the presence of two equivalents of potassium 1,2-diphenylethenide in THF at room temperature gave the diamagnetic half-sandwich complexes [Yb(η5-C5Me4SiMe2NHR)Ln(μ-I)]2 (L = THF, n = 2, L = DME, n = 1). The tert-butylamido derivative [Yb(η5-C5Me4SiMe2NHtBu)(THF)2(μ-I)]2 was characterized by X-ray structural analysis as a dinuclear complex containing a nonchelating aminocyclopentadienyl ligand. Deprotonation of the aminocyclopentadiene (C5H4tBu)SiMe2NHtBu with two equivalents of potassium 1,2-diphenylethenide in THF, followed by reaction with [YbI2(THF)2] at 60 °C, gave the trivalent ytterb…

“Cp*Ir(III)” Complexes with Hemicleaveable Ligands of the Type N-Alkenyl Imidazolin-2-ylidene. Reactivity and Catalytic Properties

2007

A series of Cp*Ir(III) complexes with N-alkenyl imidazole-2-ylidene ligands have been obtained by transmetalation of the previously obtained silver−carbene species. Two structural and electronic pa...

The Reductive σ Bond Cleavage of Barbaralane and 2,6‐Diphenylbarbaralane

1987

Barbaralane (2) and 2,6-diphenylbarbaralane (8) are synthesized in a straightforward way. The reductive cleavage of the strained hydrocarbons is achieved with alkali metals. The structure of the metallation products, in particular the bonding in the resulting allyl moieties, is elucidated by 1H- and 13C-NMR spectroscopy. The chemical behavior (oxidation, protonation, alkylation) sheds light on the modes of stabilization of the alkali metal derivatives. Die reduktive σ-Bindungsspaltung von Barbaralan und 2,6-Diphenylbarbaralan Barbaralan (2) und 2,6-Diphenylbarbaralan (8) werden auf rationelle Weise synthetisiert und die gespannten Kohlenwasserstoffe durch Reaktion mit Alkalimetallen redukti…

Synthesis of Linear and Star-Shaped Block Copolymers of Isobutylene and Methacrylates by Combination of Living Cationic and Anionic Polymerizations

1998

A new synthetic route for the preparation of polyisobutylene (PIB)-based linear and star-shaped block copolymers was developed by combining living carbocationic and anionic polymerizations. Living PIB chains were quantitatively endcapped with 1,1-diphenylethylene, leading to 1,1-diphenyl-1-methoxy (DPOMe) or 2,2-diphenylvinyl (DPV) termini, or both. Both the DPOMe- and DPV-terminated PIBs, and the mixtures of both endgroups were quantitatively metalated with K/Na alloy, Cs metal, or Li dispersion in THF at room temperature. The resulting stable macrocarbanion obtained by metalation with K/Na alloy was used to initiate living anionic polymerization of tert-butyl methacrylate (tBMA) yielding …

Gold nanostars co-coated with the Cu(II) complex of a tetraazamacrocyclic ligand

2015

The twelve-membered tetraazamacrocyclic ligand L1 bears an appended lipoic acid unit, whose disulphide ring is an efficient grafting moiety for the surface of gold nanostars (GNS). The GNS that were used featured a localized surface plasmon resonance (LSPR) absorption at ∼800 nm, i.e. in the near infrared (NIR). We investigated different approaches for coating them with the Cu(2+) complex of L1. While the direct reaction of [CuL1](2+) with as-prepared GNS led to aggregation, an initial coating step with polyethyleneglycol-thiol (PEG-SH) was found to be advantageous. Displacement reactions were carried out on pegylated GNS either with [CuL1](2+), directly generating [Cun(L1@GNS)](2n+), or wi…