Chain-end control isotactic polymers

By the same token, 1,2-insertion gives an isotactic microstructure. If the methyl group of the previously inserted molecule is upwards, the methyl group of the next molecule will be pointing downwards (see Fig. 6.17). The interaction may not be quite as strong as in the case of 2,1-insertion discussed above, but there will 

6 — HOMOGENEOUS CATALYSIS WITH TRANSITION METAL COMPLEXES 

---