Photoinduced electron transfer from N,N-dimethylaniline to 7-amino coumarins in protein-surfactant complex: slowing down of electron transfer dynamics compared to micelles.
Photoinduced electron transfer from N,N-dimethylaniline to different Coumarin dyes has been investigated in dodecyl trimethyl ammonium bromide (DTAB) micelles and in Bovine serum albumin (BSA)-DTAB protein-surfactant complex using steady-state and picosecond time-resolved fluorescence spectroscopy. We observed a slower fluorescence quenching rate in the DTAB micelles and in the protein-surfactant complex as compared to that in pure acetonitrile solution. Moreover, the observed fluorescence quenching in BSA-DTAB complex was found to be slower than that in DTAB micelles. In the correlation of free-energy change with the fluorescence quenching constant we observed a deviation in the fluorescence quenching electron transfer rate for Coumarin 151 (C-151) from the normal Marcus curve. This observation is ascribed to the stronger interaction of C-151 with the surfactant molecules present in the micelles. This is evident from the slower translation diffusion (D(L)) of Coumarin 151 compared to other probe molecules.
Chakraborty
Anjan
A
Department of Chemistry, Indian Institute of Technology, Kharagpur, West Bengal.
Seth
Debabrata
D
Setua
Palash
P
Sarkar
Nilmoni
N
D000814:Aniline Compounds / Q000737:chemistry*; D000818:Animals; D002417:Cattle; D003374:Coumarins / Q000737:chemistry*; D004579:Electron Transport; D005453:Fluorescence; D008027:Light; D008823:Micelles; D010777:Photochemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D012709:Serum Albumin; D013501:Surface-Active Agents / Q000737:chemistry*
D000814:Aniline Compounds; D003374:Coumarins; D008823:Micelles; D000644:Quaternary Ammonium Compounds; D012709:Serum Albumin; D013501:Surface-Active Agents; C015157:N,N-dimethylaniline; C022806:dodecyltrimethylammonium