Polymers with -Coordinated Metals

Other polymers with coordinating abilities such as quinoline-containing PArEs 29 and 30 have also been synthesized by Bunz et al. [28]. In this case, the polymers were sensitive to metal ions such as Pd ", La ", and Ag". ... 

Stabilizers are usually used during the reduction of metal ions to stabilize the colloidal dispersions of fine metal particles. The coordination interaction is the main factor to stabilize the metal particles. Thus, polymers with coordinating groups are good stabilizers. The choice of coordinating groups should depend on the kind of metal. 

Almost similar connectivity and magnetic properties are observed in the porous solid [Fe(C 0 )(4,4 -bpy)(H30)j] 3HjO [177]. Chains of Fe(II) metal ions bridged by squarate ligands are connected through 4,4 -bipyridines to form a framework with 1-D channels fiUed with water molecules. Interestingly, the dehydration/rehy-dration process in this coordination polymer, as well as in other isostructural polymers with other metal ions, is fuUy reversible and accompanied with a continuous change of the colour [178]. 

Heterochain Polymers with Coordinative Bonds Between Metal and Another Element... 

Opelt S, Turk S, Dietzsch E, Henschel A, Kaskel S, Klemm E. Hydrogen adsorption in a nickel based coordination polymer with open metal sites in the cyhndrical cavities of the desolvated framework. Catal... 

The oxalate ion is a good bridging ligand. Most of the insoluble transition-metal oxalates are actually coordination polymers, with the metal centers connected by bis-chelating oxalato groups. 

Phosphites. Tertiary phosphites are also commonly used and are particularly effective ia most mixed metal stabilizers at a use level of 0.25—1.0 phr. They can take part ia a number of different reactions duting PVC processing they can react with HCl, displace activated chlorine atoms on the polymer, provide antioxidant functionaHty, and coordinate with the metals to alter the Lewis acidity of the chloride salts. Typical examples of phosphites are triphenyl phosphite [101 -02-0], diphenyl decyl phosphite [3287-06-7], tridecyl phosphite [2929-86-4], and polyphosphites made by reaction of PCl with polyols and capping alcohols. The phosphites are often included in commercial stabilizer packages. 

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. 

One method of solving the kinetics dilemma is well known in coordination chemistry that is, start with a labile metal ion and render it inert during the course of the synthetic reaction. We have accomplished this in the case of zirconium(IV) by starting with tetrakis(salicylaldehydo)zirconium(IV), which is quite labile, and polymerization with 1,2,4,5-tetraaminobenzene in a Schiff-base condensation reaction in situ (6). The polymeric product contains a "double-headed" quadridentate ligand, which is much more inert to substitution. However, 1,2,4,5-tetraaminobenzene has become very expensive. Therefore, the synthesis of a zirconium polymer with 3,3, 4,4 -tetraaminobiphenyl (commercially 3,3 -diami nobenzidine) with zirconium salicylaldehyde, Zr(sal)4 (7) has been undertaken as shown below ... 

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