Stereochemistry of the free-radical polymerization of zinc methacrylates coordinated with a bidentate ligand

The polymerization of zinc methacrylates coordinated with a bidentate ligan d (1-4) was carried out in chloroform at 60 degreesC. The polymerization of these monomers gave chloroform-insoluble polymers. Stereoregularity of the polymers was estimated from H-1 NMR spectra of poly(methyl methacrylate)s (PMMAs) derived from the original polymers. Monomers 1 and 2 gave slightly different polymers compared with conventional ones obtained by polymerizati on of methacrylic acid, while 3 afforded higher amounts of isotactic polyme rs than 1 and 2. Conversely, 4 gave a polymer of high syndiotacticity. Furt hermore, the relationship between triad tacticity and monomer concentration in the feed was studied. Consequently, it was demonstrated that the struct ure of bidentate ligands coordinated with zinc ion influences the stereoreg ularity of the resulting polymers.