Polymers backbone metals/metalloids

In this book series, macromolecules containing metal and metal-like elements are defined as large structures where the metal and metalloid atoms are (largely) covalently bonded into the macromolecular network within or pendant to the polymer backbone. 

Polymers incorporating metals or metalloids in their backbones possess a very large variety of structural features. For example, the polymer can contain metal- or metalloid-carbon a bonds (46,47) or n bonds (48) in their backbones. " ... 

There are munerous examples of polymers that contain metals and metalloids coordinated to noncarbon elements. In these cases, the properties of the polymers are highly dependent on the ligands that are utilized. Polymer 49 is an example of a zinc porphyrin polymer. It was found that incorporation of different substituents (electron acceptors or electron donors) on the aromatic rings in the polymer backbone altered the electronic properties of these materials. 

There are also a number of reports that outline the synthesis of polymers containing metal-metal or metalloid-metalloid bonds in their backbones. These polymers may contain the metal a-bonded or jt-coordinated to organic ligands as shown for polymers 53 and 54, respectively. 

There are numerous examples of polymers in which the metal or metalloid is present in the sidechain of the macromolecule. Polymer 57 is an organometaUic polystyrene is which the chromium tricarbonyl moieties are 7t-coordinated to some of the benzene rings attached to polymer backbone. The polynorbomene copolymer (58) incorporates polyhedral oligomeric silsesquioxane moieties into its sidechains." ... 

Group IVA starts with carbon, which is a nonmetal, followed by silicon and germanium, which are metalloids (semimetals), and tin and lead, which are metals. All of the group IVA elements have the ability to catenate however, as you move down the group, this ability decreases. Some of the more important inorganic polymers are polysilanes, in which there are repeat Si-Si units in the polymer backbone. However, the bond energy of Si Si bonds is 222 kJ/mol, while the... 

---