Zirconium Schiff base polymer

The thermogravimetric results show that these polymers are not extremely thermally stable, unlike our zirconium Schiff-base polymers, which show thermal stability to about 500 C (24). All of the cobalt(III) p-di-ketonate polymers show decomposition before 200 C is reached. 

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 ... 

Other examples of this synthetic strategy are known for example, a recent zirconium polymer by Illingsworth and Burke (8), who joined amine side groups of a zirconium bis(quadridentate Schiff-base) with an acid dianhydride to give amide linkages. Once again, caution is necesary, as Jones and Power (2) learned when they attempted to link metal bisO-diketonates) with sulfur halides that is, they obtained insoluble metal sulfides because the p-diketone complexes which they used were fairly labile and the insolubility drove the reactions to completion in the wrong direction. 

Mercury, like zinc, appears in some chain-like structures, but apparently only in combination with other metals such as As, Sb, Nb, and Ta. Some of these have the characteristics of metallic conductors.15 Rather high molecular weights have been obtained in the preparation of 6-coordinate cobalt (III) chelate polymers with acetylacetonato and leucinato ligands, 7-coordinate dioxouranium-(VI) dicarboxylate polymers, and 8-coordinate zirconium (IV) polymers with Schiff-base ligands.77... 

The first soluble Schiff base coordination polymer was reported by Archer et al. in 1985,31 which was prepared by condensation of 1,2,4,5-tetra-amino benzene (TAB) with tetrakis(salicyladehydato)zirconium(IV) (Zr(sal)4) in dry dimethyl sulfoxide (Fig. 15). The polymer has a number-average molecular weight of up to 4.9 X 104 based on inherent viscosity, gel permeation chromatography, and elemental analyses and shows no decomposition at temperature <500°C. 

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