Metal complexes novel

Novel electron-transfer reactions mediated by alkali metals complexed with crown ethers as macrocyclic ligands 98ACR55. 

To examine potentiality of other ylides and their metal complex containing Sb, As, P, Bi, and Se as new novel initiator in polymer synthesis via living radical polymerization. 

This review deals with the chemistry and coordination complexes of isoelectronic analogues of common oxo-anions of phosphorus such as PO3, POl", RPOl" and R2POy. The article begins with a discussion of homoleptic systems in which all of the 0x0 ligands are replaced by imido (NR) groups. This is followed by an account of heteroleptic phosphorus-centered anions, including [RN(E)P(/<-NR )2P(E)NR]2-, [EP(NR)3]3-, [RP(E)(NR)2] and [R2P(E)(NR )] (E=0,S, Se, Te). The emphasis is on the wide variety of coordination modes exhibited by these poly-dentate ligands, which have both hard (NR) and soft (S, Se or Te) centers. Possible applications of their metal complexes include new catalytic systems, coordination polymers with unique properties, and novel porous materials. 

N. Toshima, in R. Barbucci, F. Ciardelli (eds.) Recent Advances and Novel Approaches in Macromolecule-Metal Complexes, Wiley-VCH, Weinheim, 2006, 1. 

A novel polysiloxane, containing the isocyanide group pendent to the backbone, has been synthesized. It is observed to react with the metal vapors of chromium, iron and nickel to afford binary metal complexes of the type M(CN-[P])n, where n = 6, 5, 4 respectively, in which the polymer-attached isocyanide group provides the stabilization for the metal center. The product obtained from the reaction with Fe was found to be photosensitive yielding the Fe2(CN-[P])q species and extensive cross-linking of the polymer. The Cr and Ni products were able to be oxidized on exposure of thin films to the air, or electrochemically in the presence of an electron relay. The availability of different oxidation states for the metals in these new materials gives hope that novel redox-active polymers may be accessible. 

Octaethylbilindione (H3OEB) is a convenient model for the bile pigment biliverdin IXa. Key redox states of this ligand as observed in its complexes are shown in Figure 14. The redox behavior of the palladium complex of octaethylbilindione was examined in order to determine the generality of the redox behavior of this group of transition metal complexes.202 A preliminary report on the novel tetrameric Pd4(OEB)2, which contains palladium) ) ions 7r-bonded to C=C bonds of the tetrapyrrole ligand, and of Pdn(OEB ) has appeared.203... 

A novel phosphinito dipeptido ligand series were prepared, and fully characterized. These ligands readily form metal complexes with Pd(H) and Pt(II) precursors. The Pd(II) complexes were investigated for their suitability in asymmetric Heck reaction using 3,4-dihydrofuran as a substrate. 

Metallomesogens are unique compounds which combine the properties of liquid crystals with that of metal complexes to generate novel electric or... 

Not included in the present review is the fascinating new chemistry which results from reaction between diazo compounds and low-valent transition-metal complexes bearing easily displaceable two-electron ligands as well as with metal-metal multiple bonds and metal hydrides whereby a variety of novel organometallic molecules could be obtained. This field has been covered, in accord with its rapid development, by successive reviews of Hermann 19 22) and Atbini23). 

Crown derivatives which are able to bind simultaneously to more than two metal ions have been synthesized such species have been termed multiloop crowns (Weber, 1982). Polynuclear cation receptors of this type provide yet another series of novel crown derivatives whose metal complexes tend to exhibit a range of unusual properties. Because of the diversity of the structures falling in this category, only a brief mention of this ligand type is presented here. 

An alternative strategy to obtain silica immobilised catalysts, pioneered by Panster [23], is via the polycondensation or co-condensation of ligand functionalised alkoxysilanes. This co-condensation, later also referred to as the sol-gel process [24], appeared to be a very mild technique to immobilise catalysts and is also used for enzyme immobilisation. Several novel functional polymeric materials have been reported that enable transition metal complexation. 3-Chloropropyltrialkoxysilanes were converted into functionalised propyltrialkoxysilanes such as diphenylphosphine propyltrialkoxysilane. These compounds can be used to prepare surface modified inorganic materials. Two different routes towards these functional polymers can be envisioned (Figure 3.4). One can first prepare the metal complex and then proceed with the co-condensation reaction (route I), or one can prepare the metal complex after the... 

The development, synthesis, and the coordination chemistry of novel metal complexes with deep binding cavities have been described. It was demonstrated that the doubly deprotona-ted forms of the macrocycles (LR)2 support the formation of... 

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