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.
Department of Chemistry, Indian Institute of Technology, Kharagpur, West Bengal.
Anjan
A
Chakraborty
Debabrata
D
Seth
Palash
P
Setua
Nilmoni
N
Sarkar
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