HYBRID EVENT: You can participate in person at Tokyo, Japan or Virtually from your home or work.
Edward Lee Ruff, Speaker at Catalysis Conferences
York University, Canada
Title : Photochemical valence isomerization to high energy products – Bicyclobutanes and Oxabicyclobutanes


The photochemical valence isomerization of 1,3-butadienes give bicyclobutane 1(X=CH2). The stereochemistry of these strained products in substituted derivatives suggest a double disrotatory ring cyclization originating from the second excited state of the diene.. The oxygen analog valence isomerization from acrolein has not been reported nor its product, oxabicyclobutane 1(X=O). DFT computations for both bicyclics showed a large basicity for the carbon analog exceeding that of the oxygen analog. The strain energy for oxabicyclobutane exceeds that for bicyclobutane. The validity of the computational method is seen from the congruence between experimental and computational values of the structural and thermochemical parameters.

Audience take-away:


  • Audience will learn about principles of photochemistry.
  • Introduction of strain and determination of strain energy.
  • Definition of proton affinity and basicity.
  • Illustration of valence isomerizations.


Edward Lee Ruff obtained his B.Sc. and Ph.D. from McGill University. He spent his postdoctoral studies at Columbia University, New York. He is currently Emeritus Professor after 45 years at York University. He has over 140 publications in peer reviewed journals and was awarded the Fellowship of the Canadian Institute of Chemistry. He has had 41 years of continuous government research support. His research also lead to two patents. He is also consultant for patent attorneys in litigation cases between generic and brand name drug companies. He has been involved in the outreach program giving lectures on patent issues between generic and brand name drugs.