Chen Ming, Ghiggino Kenneth P, Thang San H, White Jonathan, Wilson Gerard J
School of Chemistry, The University of Melbourne, Victoria 3010, Australia.
J Org Chem. 2005 Mar 4;70(5):1844-52. doi: 10.1021/jo047899d.
A novel free radical trapping reaction based on a stepwise radical reversible addition-fragmentation mechanism has been utilized to synthesize a series of acenaphthenyl dimers and trimers. The synthetic procedure involves the reaction of acenaphthylene with dithiobenzoate compounds (S=C(Ph)-SR) in the presence of a free radical initiator followed by reduction of the dithiobenzoyl end group with tributyltin hydride. Stereoisomers of the compounds have been isolated and their structures determined by proton NMR and X-ray crystallography. The solution fluorescence of the compounds has been characterized to reveal the requirements for intramolecular excimer (excited-state dimer) formation. Only in compounds containing identical stereochemical arrangements of adjacent acenaphthenyl groups is excimer fluorescence observed following photoexcitation.
