title: Solvent and rotational relaxation of coumarin 153 in a protic ionic liquid dimethylethanolammonium formate.
abstract: The solvent relaxation and orientational dynamics of coumarin 153 (C-153) was investigated in N,N-dimethylethanolammonium formate (DAF) with a variation of temperature. DAF is a protic room-temperature ionic liquid, comprised of nonaromatic cations. Both solvent relaxation and orientational dynamics of C-153 in DAF are linearly well-correlated with the bulk viscosity at different temperatures. We optimized the geometry of DAF using quantum chemical calculations using density functional theory methods. The optimized structure of DAF shows a nonbonded interaction between cation and anion, which suggests that a hydrogen bond is formed between hydrogen atoms attached to the nitrogen atom of the cation with the oxygen atom of the anion in DAF.
authors.affiliation: Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, WB, India.
authors.forename: Debabrata
authors.initials: D
authors.lastname: Seth
authors.forename: Souravi
authors.initials: S
authors.lastname: Sarkar
authors.forename: Nilmoni
authors.initials: N
authors.lastname: Sarkar