TY - JOUR
T1 - Excited state dynamics of 9,9′-bianthryl in room temperature ionic liquids as revealed by picosecond time-resolved fluorescence study
AU - Khara, Dinesh Chandra
AU - Paul, Aniruddha
AU - Santhosh, Kotni
AU - Samanta, Anunay
N1 - Funding Information:
This work is supported by the Ramanna Fellowship of the Department of Science and Technology, Government of India. D C K and K S thank the Council of Scientific and Industrial Research (CSIR) for fellowships.
PY - 2009/1/1
Y1 - 2009/1/1
N2 - Picosecond time-resolved fluorescence measurements have been carried out on 9,9′-bianthryl in three imidazolium ionic liquids to probe the excited state dynamics. In the early time-scale, the fluorescence spectra of bianthryl have been found to consist of emission from both locally excited (LE) and charge transfer (CT) states. The LE → CT relaxation time, as estimated from the decay of the fluorescence intensity of the LE emission, is found to vary between 230 and 390 ps, while the average solvent relaxation time, as estimated from the analysis of time-dependent fluorescence Stokes shift, is found to vary between 620 ps and 1840 ps, depending on the viscosity of the ionic liquids. The results confirm that while in conventional less viscous solvents the CT formation kinetics of bianthryl occurs simultaneously with the solvation dynamics, in ionic liquids the two processes mostly occur in different time scales.
AB - Picosecond time-resolved fluorescence measurements have been carried out on 9,9′-bianthryl in three imidazolium ionic liquids to probe the excited state dynamics. In the early time-scale, the fluorescence spectra of bianthryl have been found to consist of emission from both locally excited (LE) and charge transfer (CT) states. The LE → CT relaxation time, as estimated from the decay of the fluorescence intensity of the LE emission, is found to vary between 230 and 390 ps, while the average solvent relaxation time, as estimated from the analysis of time-dependent fluorescence Stokes shift, is found to vary between 620 ps and 1840 ps, depending on the viscosity of the ionic liquids. The results confirm that while in conventional less viscous solvents the CT formation kinetics of bianthryl occurs simultaneously with the solvation dynamics, in ionic liquids the two processes mostly occur in different time scales.
KW - Bianthryl
KW - Excited state relaxation dynamics
KW - Ionic liquids
KW - Solvent relaxation dynamics
KW - Time-resolved fluorescence
UR - http://www.scopus.com/inward/record.url?scp=67949118907&partnerID=8YFLogxK
U2 - 10.1007/s12039-009-0035-6
DO - 10.1007/s12039-009-0035-6
M3 - Article
AN - SCOPUS:67949118907
VL - 121
SP - 309
EP - 315
JO - Proceedings of the Indian Academy of Sciences: Chemical Sciences
JF - Proceedings of the Indian Academy of Sciences: Chemical Sciences
SN - 0253-4134
IS - 3
ER -