Tethered Ligand

The supported complex [Rh(cod)(POLYDIPHOS)]PF6, obtained by stirring a CH2C12 solution of [RhCl(cod)]2 and Bu4NPF6 in the presence of a diphenyl-phosphinopropane-like ligand tethered to a cross-linked styrene/divinylbenzene matrix (POLYDIPHOS), forms an effective catalyst for the hydrogenation of quinoline (Fig. 16.8) [84]. Under relatively mild experimental conditions (80 °C, 30 bar H2), quinoline was mainly converted to THQ, though appreciable formation of both 5,6,7,8-THQ and decahydroquinoline also occurred (Scheme 16.20). 

Another useful strategy for the confinement of metal centres in molecular sieves is the covalent attachment of coordination complexes via a spacer ligand (tethering). The use of surface-fixed N-donor ligands (Lewis base Hg-ands) coordinating dioxomolybdenum M0O2 moieties has been described mainly by Thiel et al. [22,23,28,29] and Gonsalves et al. [15,24,40]. 

Table4 Cyclooctene epoxidation with TBHP/MCM-spacer ligand-tethered Cp Mo(CO)3R complexes... 

An interesting observation has been made with the ligand tethering two /Pr2-tacn units by a m-xylyl spacer, /Pr4-/w-Xyl [176], Concentration-dependent spectra and decay rates are found for the oxygenated species, indicating preferential formation of bis- u-oxo species at high concentrations but a J,-r 2 r 2-... 

Fig-i Electron tunneling wires consist of a substrate or ligand tethered to a redox-active head group... 

Although there are many examples of diimine ligands tethered to organic chromophores, most compounds are based upon 2,2 -bipyridine and 2,2, 2"-terpyridine structures, the subject of other reviews in this series. Historically, (1) and its derivatives have been largely unexplored for... 

Hh ligand tethered to Palmitoylated Wnt with serine/threonine membrane of ligand binds seven... 

Fig. 28.16 The thrombin receptor, a member of the PA family of receptors, expresses an endogenous ligand — tethered ligand — at the extracellular AZ-terminc subsequent to proteolytic cleavage.

The dynamics of bimolecular C-Li exchange in several allylic lithium compounds with ligands tethered at C2 has been investigated by Fraenkel et alF by the use of the Li-C couplings yielding the thermodynamic data of this process. 

Burford, N., Herbert, D.E., Ragogna, P.J., McDonald, R. and Ferguson, M.J., Diphosphine-phosphenium coordination cortplexes representing monocations with pendant donors and ligand tethered dications, J. Am. Chem. Soc. 126 (51), 17067-17073 (2004). 

Tolman and co-workers have also synthesized a model system which undergoes endogenous aromatic hydroxylation using an amine and a pyridine ligand tethered to an arene. (Scheme 6) Unlike our XYL-H system, oxygenation of copper(I)-complex forms a bis-M.-oxo-dicopperClll) complex instead of a peroxodicopper(II) complex. Upon decomposition, the... 

Because NHC ligands may act as Lewis base donors, it was not surprising they could also coordinate metals incapable of 7i-backbonding such as the alkaline earth metals Be or Mg. Today there are many examples known of N-het-erocyclic carbene ligands tethered to early transition metals, lanthanoid and actinoid metals. ... 

Another ligand prepared in this series has a 1,10-phenanthroline ligand tethered to ethynylferrocene and is shown as Again a number of rigid rod type ferrocenylpyridines and bipyridines have been obtained by coupling... 

FIGURE 18. (a) A tripodal technetium chelator is based on three oxime ligands tethered through an acyclic boronate triester, (b) Borosilicate macrocycles and (c) cages have been formed as building blocks and (d) assembled via coordinative ditopic Lewis bases. 

The end groups of an amphiphilic comb copolymer used to create a robust hydrophilic coating on the final particles were selectively functionalized to obtain latex particles with a controlled density of ligands tethered to their surfaces [125]. The final latexes were used to form cell-resistant and cell-interactive surfaces. 

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