Unit Variability Due to the Presence of Stable Metal Isotopes

Unit Variability Due to the Presence of Stable Metal Isotopes 

Unit variability as a result of stable metal isotopes is fairly well known for traditional polymers. It is associated and caused by stable isotopes of the polymerforming elements ( C, H, 0, N etc.). In some cases, certain metals isotopes are enriched during MCM synthesis. For example, enrichment in Fe is used for y-resonance studies of the polymerization products of Fe + acrylates (scheme 17). In other cases, stable isotopes of tin and vanadium, were used. 

Anomalies in Metallopolymeric Chains Cansed by the Diversity of Chemical Binding of a Metal to Polymerizable Ligands 

Unit variability as a result of the diversity of chemical binding of a metal to polymerize ligands can be demonstrated most clearly by considering metal salts of unsaturated carboxylic acids. The polydentate properties of the carboxylate group, RCOO, are well known. Monodentate and bidentate types of metal binding are typical (scheme 18). Nevertheless, carboxylates can also act as tridentate or tetradentate Ugands in reactions with even when multiple bonds do not participate in complexation. 

In the case of thermal polymerization, the munber of modes of metal binding to carboxylate groups usually increases sharply, because of recombination polymerization processes. Both the monomer itself (Cu diacrylate) and the transient polymer can undergo thermolysis. At higher temperatmes, the role of the latter route increases—that is, terminal metal carboxylate groups are much more susceptible to decarboxylation than the internal groups. 

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