简介:Bothdirectandsensitizedirradiationsoftheendotitlecompoundleadtoadecarbony-lationproduct,4-isopropylbiphenyl,viaNorrishType1reaction,whiletheexoisomergivesacarbeneintermediateandsubsequentlyformaldehyde2-biphenylylisopropylhemiacetal,whichinturngraduallydecomposestodimethylphenylbenzylalcoholatroomtemperature.Thetripletpathwaydominatesthephotoreactionoftheexoisomer.Thesingletandtripletlifetimesofthereactantarefoundtobe0.29nsand5.4μs,respectively.~3(n,π~*),~1(n,π~*),~3(π,π~*)electronicconfigurationsoftheexoisomerand~3(π,π~*)oftheendoisomerarephotochemicallyactive,but~1(π,π~*)oftheendoisomershowsindirectphotoreactivity.