Agents, polymeric divalent

Early attempts at producing dialkyltin compounds yielded polymers. More recently, Neumann has found several synthetic routes to reactive R2Sn intermediates which can be trapped by oxidative-addition reactions (J). In the absence of trapping agents the divalent tin compound polymerizes. Lappert and co-workers have shown that the bulky bistri-methylsilylmethyl ligand stabilizes the divalent tin species toward polymerization. This stable divalent tin species thus provides an excellent starting material for investigating a wide variety of oxidative-addition reactions, as shown in Fig. 10 (78). 

Hydrogels can be made by a number of methods, but one of the most widely used methods is free radical polymerization of vinyl monomers. Examples of vinyl monomers used in our laboratory are shown in Table 1. Monomers are crosslinked with divalent monomers such as A,A -methyl-enebisacrylamide. Biodegradable crosslinking agents can also be used as long as they have bifunctionality. 

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