Investigation of heavy atom effect of halide alkanes in beta-cyclodextrin induced room temperature phosphorimetry

Twenty-one alkyl halides were examined in detail for their heavy atom effect in beta-cyclodextrin induced room temperature phosphorescence (beta-CD-RTP) with five polycyclic aromatic as mode compounds. The following conclusions were drawn from the experimental results. (1) The heavy atom enhancement effect (HAEE) of halogens in halide alkane are increased in the trend of Br > Cl much greater than I. (2) Among the bromoalkanes examined, dibromoalkanes have the strongest HAEE, next the monobromoalkanes. For tri- and tetrabromoalkanes, very weak HAEE was observed. (3) A new heavy atom pertuber, t-butyl chloride, was found to have excellent ability of inducing RTP of polycyclic aromatic compounds. (4) The phosphorescence decay characteristics of the phosphorescent molecules, tau(p), had been measured in the presence of halide alkanes and used to explain the luminescence mechanism of CD-RTP.