Polymers metal chelate

By the transformation of a sensitizer, light energy is stored by forming quadricyclane. In the back reaction using a catalyst the stored energy is set free The most active catalysts are low molecular on N4- and N202-chelates mainly containing cobalt Polymer metal chelates are easily separable from liquids when fixed on polymer beads. 

When KCl was added to the solution at P/D = 6.5 in Fig.6, the amplitude of the negative dichroism decreased until it became positive again at [KCl] = 2 x 10" M. Added K ions might compete with Co-(oPAN)2+ for occupying the free styrenesulfonic residues. Accordingly the observed KCl effects lead us to the conclusion that the number of polymer residues available for one chelate was a dominant factor in determing the structure of a polymer-metal chelate complex. 

The literature of polyimines is extensive [164-173]. A number of researchers have tried to synthesize high molecular weight polymers but failed due to poor solubility in organic solvents. Polyimines are of great interest because of their high thermal stability [174-176], ability to form metal chelates [174-177], and their semiconducting properties [178-181]. Due to insolubility and infusibility, which impeded characterization of the molecular structure, the application of these polymers is very limited and of little commercial importance. 

Metal deactivators (MD) act, primarily, by retarding metal-catalyzed oxidation of polymers they are, therefore, important under conditions where polymers are in contact with metals, e.g., wires and power cables. Metal deactivators are normally polyfunctional metal chelating compounds (e.g.. Table la, AO 19-22) that can chelate with metals and decrease their catalytic activity [21]. 

Metal chelates have also been used in photografting and crosslinking of different types of polymers [61,65-67]. 

UV absorbers have been found to be quite effective for stabilization of polymers and are very much in demand. They function by the absorption and harmless dissipation of the sunlight or UV-rich artificial radiation, which would have otherwise initiated degradation of a polymer material. Meyer and Geurhart reported, for the first time in 1945 [10], the use of UV absorber in a polymer. They found that the outdoor life of cellulose acetate film was greatly prolonged by adding phenyl salicylate (salol) [10]. After that, resorcinol monobenzoate, a much more effective absorber, was introduced in 1951 [11] for stabilization of PP, but salol continued to be the only important commercial stabilizer for several years. The 2,4-dihydroxybenzophenone was marketed in 1953, followed shortly by 2-hydroxy-4-methoxybenzophenone and other derivatives. Of the more commonly known UV absorbers, the 2-hydroxybenzophenones, 2-hy-droxy-phenyl-triazines, derivatives of phenol salicylates, its metal chelates, and hindered amine light stabilizers (HALS) are widely used in the polymer industry. 

Wohrle, D. Polymer Square Planar Metal Chelates for Science and Industry. Synthesis, Properties and Applications. Vol. 50, pp. 45— 134. 

Soluble Metal Chelate Polymers of Coordination Numbers 6, 7, and 8... 

ARCHER ETAL. Soluble Metal Chelate Polymers... 

Tsafack V.C., Marquette C.A., Pizzolato F., Blum L.J., Chemiluminescent choline biosensor using histidine-modified peroxidase immobilized on metal-chelate substituted beads and choline oxidase immobilized on anion-exchanger beads co-entrapped in a photocrosslinkable polymer, Biosens. Bioelectron, 2000 15 125-133. 

Metal catalysts, 10 46-47 Metal-catalyzed addition, polymers prepared by, 15 179-180 Metal chelation, 9 424 Metal chloride salts, 13 817-818 Metal chlorides, decomposition by acids, 13 822-824 Metal cleaning... 

Macromolecular metal complexes can be classified into three main categories, taking into consideration the manner of binding of a metal compound to suitable macroligands [33] (Fig. 1). Type 1 metal complexes are those with the metal ion or metal chelate at a macromolecular chain, network, or surface. One possible approach to synthesize such polymers is using the polymerization of vinyl-substituted metal complexes. 

In this review, well-defined metal-containing PAEs are described whose primary structure is represented by one of the schematic drawings A-C and E shown in Fig. 2. In contrast to the structures shown in the A-C systems, E has a conjugated phenyleneethynylene with metal chelates as end groups. PAEs containing metal complex as side groups (D) have, up to now, not been described in the literature. The classes of compounds such as metal-bridged alkynes, the poly(metallayne)s, and polymer carbyne complexes (structures G and H) do not in fact represent PAEs. 

We prepared a series of pendant-type polymer-metal complexes having a uniform structure by the substitution reaction between a polymer ligand and a Co(III) or Cr(III) chelate, the chelate being inert in ligand-substitution reactions1,2 A poly-mer-Co(III) complex, e.g. ci s-[Co(en)2(PVP)Cl]Cl2 (en=ethylenediamine, PVP= poly(4-vinylpyridine)) i 7, was prepared as follows11 ... 

In the search for a reactive functional group which could be substituted on the acetylacetonate ring, chloromethylation of these chelates was attempted. The initially formed products were too reactive to be characterized directly. Treatment of rhodium acetylacetonate with chloromethyl methyl ether in the presence of boron trifluoride etherate afforded a solution of a very reactive species, apparently the chloromethyl chelate (XXX) (26). Hydrolytic workup of this intermediate yielded a polymeric mixture of rhodium chelates, but these did not contain chlorine On the basis of evidence discussed later on electrophilic cleavage of carbon from metal chelate rings and on the basis of their NMR spectra, these polymers may be of the type shown below. Reaction of the intermediate with dry ethanol afforded an impure chelate which is apparently the trisethyl ether (XXXI). Treatment of the reactive intermediate with other nucleophiles gave intractable mixtures. 

Template Polymers. Template effects in chelating polymers constitute an interesting development in the field of metal containing polymers. The Template effects are interpreted by the fact that the small molecule is templating a pattern in the macromolecule which can be recognized by the same molecule in a subsequent process. The idea is to prepare a polymer from the metal-chelated monomer, to remove the metal ion, and then to measure the selectivity of the prepared polymer for the metal ion of the template [36]. Typical examples of template systems are 4-vinyl-4 -methylbipyridine (Neckers [36]) and 1-vinyl-imidazole (Tsuchida [37]). These are polymerized in presence of divinylbenzene [36] and appropriate metal salts (Co2+, Cu2+, Ni2+, Zn2+). The template metal ions are removed by acid leaching and the polymer subsequently used for metal ion absorption studies (Fig. 16). 

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