Polymer Engineering Interview Questions and Answers
Question - 21 : - Explain What Is Meant By "c2 Symmetry" And "mirror Plane Symmetry". Can A Molecule With "mirror Plane Symmetry" Ever Be Chiral?
Answer - 21 : -
"C2 symmetry" means that 180o rotation about an axis through the molecule results in a geometry equivalent to the starting geometry. "Mirror plane symmetry" means that one half of the molecule can be perfectly reflected into the other half through a symmetry plane. Molecules with mirror plane symmetry cannot be chiral.
Question - 22 : - Consider A Homogeneous Zirconium Catalyst In Which Two Cyclopentadienyl Ligands Are Connected By A —ch2–ch2— Bridge. Which Symmetry Elements Does The (bridged-cp2)zr Moiety Possess? What Is The Expected Tacticity Of The Polypropylene Produced Using This Type Of Catalyst? Why?
Answer - 22 : -
The (bridged-cp2)Zr moiety possesses both C2Zr catalyst discussed in Session 5, it would be expected to produce atactic polypropylene, since the methyl group on the propylene would have no up/down preference.