Question

use diagram and explain why a π,π* transition undergoes a red shift, while a n,π* transition undergoes a blue shift?

Answer 1

• 1 X transition undergoes Red shift because These transitions involve moving an electron from Trbanding to T- antibanding orbital. The molar absorptivitis au abart 10000 Lmolasan- and undergo a Red shift / Bathochromie Shift with Solvent interactions. This is because due to raising of the ground state Energy, or lowering of the excited State energy. i los A Non-polar 2. n DES DEJAE2 - Polar solvent transition undergon Blue shift because These transitions involve moving an electron from non-bending electron Pail to antibanding (A-orbital). There molar assorptivities are about 2000 (molt ant and Undergo blue Shift with Solvent interactions - The lonce pair interacts with the Polar Solvent and the Solvent aligns itself with The ground State When the excited State emerges, the solvent molecules do not have time to reallange inorder to Stabilize the excited State This causes a lowering of energy f the ground state & not the excited state and hence causes blue Shift Dei Tata ofa > DEI Scanned with CamScanne A Non-polanc Polar Solvent