The pentadienyl radical, has its unpaired electron delocalized over three carbon atoms

Chapter 0, Problem 15-36

(choose chapter or problem)

The pentadienyl radical, has its unpaired electron delocalized over three carbon atoms. (a) Use resonance forms to show which three carbon atoms bear the unpaired electron. (b) How many MOs are there in the molecular orbital picture of the pentadienyl radical? H2CCHCHCHCH2 # , [6 + 2] C O H Cl H H Cl CH3 COOCH3 CH3 O O H H H H O O O CN CN O H H Cl Cl Cl Cl Cl Cl Cl Cl chlordane Cl Cl Cl Cl Cl Cl aldrin HH CN O O S CN furan: maleimide: O O O N H O O O hexa-1,3,5-triene maleic anhydride (b) Draw the structure of the desired product, and propose a structure for the actual product. (c) Show why he expected the MS base peak to be at , and show how your proposed structure would give an intense peak at . M29 M43 (c) How many nodes are there in the lowest-energy MO of the pentadienyl system? How many in the highest-energy MO? (d) Draw the MOs of the pentadienyl system in order of increasing energy. (e) Show how many electrons are in each MO for the pentadienyl radical (ground state). (f) Show how your molecular orbital picture agrees with the resonance picture showing delocalization of the unpaired electron onto three carbon atoms. (g) Remove the highest-energy electron from the pentadienyl radical to give the pentadienyl cation. Which carbon atoms share the positive charge? Does this picture agree with the resonance picture? (h) Add an electron to the pentadienyl radical to give the pentadieny