TRANSFER OF ENERGY FROM THIACYANINE TO ACRIDINE-ORANGE AND FORMATION OF EXCIPLEX BETWEEN THE 2 DYES BOUND TO SURFACTANTS

Energy transfer from donor thiacyanine and to the acceptor acridine or ange and formation of exciplex between the dyes have been probed fluor imatrically in the presence of different concentrations of the surfact ants sodium deoxycholate (NaDC), sodium cholate (NaC) and sodium salt of N-lauroyl sarcosine (NLS). All the three surfactants enhance the fl uorescence of thiacyanine with efficiency of the order NaDC>NaC simila r or equal to NLS. Results show that NLS facilitates both energy trans fer and exciplex formation, whereas premicellar and micellar concentra tions of NaDC favour only exciplex formation, but NaC facilitates neit her phenomenon. The difference in behaviour of the surfactants has bee n thought to be due to difference in size and rigidity of the respecti ve micelles. Premicellar concentrations of NLS favours exciplex format ion and micellar and post micellar conditions favour energy transfer. (C) 1998 Elsevier Science B.V.